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AP State Syllabus AP Board 9th Class Physical Science Important Questions Chapter 5 What is inside the Atom?

AP State Syllabus 9th Class Physical Science Important Questions 5th Lesson What is inside the Atom?

9th Class Physical Science 5th Lesson What is inside the Atom? 1 Mark Important Questions and Answers

Question 1.
Write any two limitations of Rutherford’s atomic model.
Answer:

• The revolving electron would lose energy continuously and get directed towards positively charged nucleus and eventually crash into the nucleus.
• If this is true, the atoms would become highly unstable and the matter would not exist, but matter exists.

Question 2.
In Rutherford’s experiment, when the alpha particles hit the foil, Rutherford expected that all the alpha particles would be deflected by small angles. Why did Rutherford expect the above observation?
Answer:
Rutherford thought that positive charge is distributed throughout the atom.

Question 3.
Write an application of isotopes in the field of medicine.
Answer:

• The isotope of iodine is used in the treatment of goitre.
• The istope of cobalt is used in the treatment of cancer.

9th Class Physical Science 5th Lesson What is inside the Atom? 2 Marks Important Questions and Answers

Question 1.
What is valency? Write valency of hydrogen.
Answer:

• The number of electrons present in outer most orbit of an atom is called its valency.
• Valency of hydrogen is 1.

Question 2.
Observe the table given below.

Shell	Shell No	Maximum number of electrons in a shell
K	1	2(1)2 = 2
L	2	2(2)2 = 8
M	3	2 (3)2 = 18
N	4	2(4)2 = 32

Answer the following questions.
i) Which Shell has highest number of electrons?
ii) Write the general form of the formula to find maximum number of electrons in each shell?
Answer:
i) 0 Shell ‘N’.
ii) 2n² (n = 1, 2, 3, ……..)

Question 3.
Convert 36g of water into mole?
Answer:
Water molecular formula = H₂O
At.wt. of water = (2 × 1) + 16 = 18
1 mole, water = 18 gr.
36g. of water = \(\frac{36}{18}\) = 2 moles

9th Class Physical Science 5th Lesson What is inside the Atom? 4 Marks Important Questions and Answers

Question 1.
Fill the blanks in the table using the given information. (Isotopes are not included).

Answer:

Question 2.
Fill in the missing information in the table given below.

Answer:

Question 3.
Draw the figures showing arrangement of electrons for the given elements.
1. Helium, Oxygen, Argon.
Answer:
1) Helium
2) Oxygen
3) Argon

2. How many neutrons are present in the nucleus of Sodium?
Answer:
Sodium = ²³₁₁Na
Neutrons = 23-11 = 12

Question 4.
a) Draw neat diagrams indicating the nucleus and arragement of electrons in different shell for the following elements?
i) Helium
ii) Carbon
iii) Argon
Answer:

b) Which of the above element is unstable? Why?
Answer:
Carbon is unstable. The nudes of carbon-14 atoms are unstable because they have too many neutrons relative to protons, so they gradually decay.

9th Class Physical Science 5th Lesson What is inside the Atom? Important Questions and Answers

9th Class Physical Science 5th Lesson What is inside the Atom? 1 Mark Important Questions and Answers

Question 1.
Write the names of isotopes of Hydrogen.
Answer:
Hydrogen, deuterium, tritium.

Question 2.
Which element has maximum number of isotopes?
Answer:
Cesium and Helium are the elements having maximum number of isotopes.

Question 3.
What is maximum number of electrons present in M-shell?
Answer:
Maximum number of electrons present in M-shell is 2 × 32 = 2 × 9 = 18.

Question 4.
Which atom doesn’t contain neutron in its nuclear?
Answer:
Hydrogen.

Question 5.
Show the arrangement of electrons in phosphorus through a diagram.
Answer:
Atomic number of phosphorus is 15.
Distribution of electrons : 2, 8, 5.

Question 6.
Who proposed rules for electron distribution in an atom?
Answer:
Bohr and Bury.

Question 7.
What is the first rule of Bohr and Bury for electron distribution in an atom?
Answer:
The maximum number of electrons present in a shell is given by the formula 2n², where ‘n’ is the shell number, which takes values 1, 2, 3, 4,

Question 8.
Write the second principle of Bohr – Bury.
Answer:
Each energy level or electron shell is further divided into sub-shells. The maximum number of electrons that can be accommodated in each shell is 8.

Question 9.
Write the third law of Bohr – Bury.
Answer:
Electrons cannot be filled in a given shell unless the inner shells are completely filled i.e., shells are filled in step-wise manner.

Question 10.
What is an octet?
Answer:
An outermost shell which has 8 electrons is said to possess an octet.

Question 11.
Define atomic number.
Answer:
Atomic number :
Atomic number is the number of protons in the nucleus of an atom, denoted by ‘Z’.

Question 12.
Define atomic mass number.
Answer:
Atomic mass number:
Atomic mass number is the number of protons plus the number of neutrons, denoted by A.
∵ A = Z + N

Question 13.
On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.
Answer:
The negative and positive charges are equal in magnitude are present in atom. So, the atom as a whole is electrically neutral as whole according to Thomson model.

Question 14.
On the basis of Rutherford model of an atom, which sub-atomic particle is present in the nuclear of an atom?
Answer:
α – particles are repelled by the nucleus. So it contains positive charged particle that is proton.

9th Class Physical Science 5th Lesson What is inside the Atom? 2 Marks Important Questions and Answers

Question 1.
What are the postulates of Thomson’s model of the atom?
Answer:
J.J. Thomson proposed a model of atom in 1898. The main postulates are

1. An atom is considered to be a sphere of uniform positive charge and electrons are embedded into it.
2. The total mass of the atom is considered to be uniformly distributed throughout the atom.
3. The negative and the positive charges are supposed to cancel out the atom as a whole is electrically neutral.

This model is commonly known as plum pudding model or watermelon model.

Question 2.
What are the features of Rutherford’s model of atom?
Answer:
In 1909, Rutherford proposed a model of atom based on the alpha particle scattering experiment. The main features are

1. All the positively charged material in an atom formed a small dense centre, called the nucleus of the atom. The electrons were not a part of nucleus.
2. The negatively charged electrons revolve around the nucleus in well-defined orbits.
3. The size of the nucleus is very small as compared to the size of the atom.

This model is known as planetary model because the electrons revolve around the nucleus as planets revolve around the sun.

This model failed to explain the stability of atom.

Question 3.
Write the rules proposed by Bohr – Bury for electron distribution.
Answer:
Bohr-Bury proposed the following rules for electron distribution.
Rule – 1 :
The maximum number of electrons that can be accommodated in each shell is given by a formula 2n2. Where n is the shell number, which takes the values 1, 2, 3,….
Ex : For K shell, n = 1

∴ Maximum number of electrons in K shell = 2(1)2 = 2 × 1=2

Rule – 2 : Each energy level or electron shell is further divided into subshell. The maximum number of electrons that can be accommodated in each subshell is 8.

Rule – 3: Electron cannot be filled in a given shell unless the inner shells are completely filled.

Question 4.
Explain the distribution of electrons in oxygen atom using Bohr-Bury principle.
Answer:

1. Atomic number of oxygen is 8.
2. Hence it has 8 protons and 8 electrons.

Step -1 :
The K-shell can accommodate maximum 2 electrons, so the first 2 electrons fill the shell of n = 1.

Step – 2 :
The other 6 electrons will fill the higher shell n = 2 or the L-shell.
Step – 3 :
Then the electronic structure for oxygen atom is 2, 6.

Question 5.
Fluorine atom contains 7 electrons in the outermost shell. But its valency is ‘1’. Explain.
Answer:

• Valency is the number of electrons present in the outer most orbit of an atom.
• The distribution of electrons in fluorine (atomic number 9) is 2, 7.
• Hence the valency of fluorine could be 7.
• But it is easier to fluorine to gain one electron for becoming octet.
• Hence its valency is determined by subtracting seven electrons from 8 and which gives you a valency ‘1’ for fluorine.

Question 6.
What is the importance of valency?
Answer:
1) An atom with 8 electrons or an octet in their outer most shell is chemically stable or does not combine other atoms.
Ex : Ne, Ar, etc.

2) An atom with duplet or 2 electrons in its outer most shell is also more stable when there is only one shell present in it.
Ex : He

3) Atoms of an element thus react with other atoms. So as to achieve an octet in their shell.

4) When elements reacts to form compounds, their atoms must be combining in such a way that they can attain the stable electron distribution of noble gases or inert gases.

Question 7.
How can an atom achieve octet?
Answer:
An atom can achieve an octet by two ways.

1. One by transfer of electrons.
2. Other by sharing of electrons.
3. Both the processes results in the formation of bonds between atoms.

Question 8.
Explain the notation : \({ }_{9}^{19} \mathrm{F}\)
Answer:

• F is the symbol of element (Fluorine).
• 9 is the atomic number.
• 19 is the mass number.
• Hence fluorine has 9 protons and (19 – 9 = 10) 10 neutrons in its nucleus.
• 9 electrons are revolving around the nucleus.

Question 9.
Define isotope and give two examples.
Answer:
Isotope :
The atoms of the same element which have the same number of protons but have different number of neutrons are called isotopes.

Question 10.
“Sulphur shows multiple valency.” Explain this.
Answer:
a) Atomic number of sulphur is 16.
b) The distribution of electrons is 2, 8, 6.
c) Hence the valency should be ’6′.
d) But it is easier to sulphur to gain 2 electrons than loosing 6 electrons to become octet. Hence its valency would become 2.
e) So, sulphur shows multiple valency, i.e., ‘2’ or ‘6’.

Question 11.
Show the arrangement of electrons in first 18 elements schematically.
Answer:

Question 12.
What are the applications of isotopes in our daily life?
Answer:
Applications of isotopes :

1. Some isotopes are used for solving chemical and medical mysteries.
2. Isotopes are also commonly used in the laboratory to investigate the steps of a chemical reaction.
3. The isotope of uranium is used as a fuel in nuclear reactors.
4. The isotope of iodine is used in the treatment of goitre.
5. The isotope of cobalt is used in the treatment of cancer.

Question 13.
If an atom contains one electron and one proton, will it carry any charge or not?
Answer:
It will not carry any charge because proton is positively charged particle and electron is negatively charged particle. So they would neutralise each other.

Question 14.
What do you think would be the observation if the a – particle scattering experiment is carried out using a foil of metal other than gold?
Answer:
Gold has highest malleability and ductility. Extremely very thin foil can be prepared by using Gold, which is not possible with other metals. So, we will not get same type of results using other metals.

Question 15.
Helium atom has an atomic mass of 4u and two protons in its nucleus. How many neutrons does it have?
Answer:
Atomic mass due to protons = 2 × 1 = 2 u
Neutrons have almost same mass as protons.
Mass of neutrons = 4 – 2 = 2u
∴ Number of neutrons = 2

Question 16.
Write the distribution of electrons in carbon and sodium atoms.
Answer:
Distribution of electrons in carbon is 2, 4.
Distribution of electrons in sodium is 2, 8, 1.

Question 17.
If K and L shells of an atom are full, then what would be the total number of electrons in the atom?
Answer:
Number of electrons present in K shell = 2(1)² = 2 × 1=2
Number of electrons present in L shell = 2(2)² = 2 × 4 = 8
Total number of electrons in the atom = 2 + 8 = 10

Question 18.
If number of electrons in an atom is 8 and number of protons is also 8, then
i) what is the atomic number of atom?
ii) what is the charge on the atom?
Answer:
i) The atomic number of atom is 8.
ii) The electronic configuration of atom is 2, 6. By gaining two electrons it will get nearest inert gas configuration Neon. So, the charge on the atom is – 2.

Question 19.
Chlorine occurs in two isotopic forms that is \({ }_{17}^{35} \mathrm{Cl}\) and \({ }_{17}^{37} \mathrm{Cl}\). The percentage of these forms are 75% and 25% respectively. Find atomic weight of chlorine atom?
Answer:
The atomic mass of an element is taken as an average mass of all the naturally occurring atoms of the sample element.
The average atomic mass of chlorine atom on the bases of above data

Question 20.
For the symbol H, D and T tabulate three sub atomic particles found in each of them.
Answer:

Question 21.
Na⁺ has completely filled K and L shells. Explain.
Electron configuration of Na+ is 2, 8.
So, sodium has completed filled K and L shells because the maximum number of electrons filled in K and L shells are 2 and 8 electrons respectively.

Question 22.
If Bromine atom is available in the form of say, two isotopes \({ }_{35}^{79} \mathrm{Br}\)(49.7%) and \({ }_{35}^{81} \mathrm{Br}\) (50.3%), calculate the average atomic mass of Bromine atom.
Answer:

Question 23.
The average atomic mass of sample of an element X is 16.2 u. What are the percentages of isotopes \({ }_{8}^{16} \mathrm{X}\) and \({ }_{8}^{18} \mathrm{X}\)?
Answer:

∴ The percentage of first isotope is 90 and percentage of second isotope is 10.

Question 24.
If Z = 3, what would be the valency of the elements? Also, name the element?
Answer:
Electronic configuration of element is 2, 1 and the element is Lithium.
The element will get nearest inert gas Helium configuration by loosing one electron. So its valency is 1.

Question 25.
Composition of nuclei of two atomic species X and Y are given as under.

	X	Y
Protons	6	6
Neutrons	6	8

Give the mass number of X and Y. What is the relation between the two species?
Answer:
Mass number of X = 6 + 6 = 12
Mass number of Y = 6 + 8 = 14
So these two species have same atomic number (same number of protons) and different mass numbers. Therefore these two species are isotopes.

9th Class Physical Science 5th Lesson What is inside the Atom? 4 Marks Important Questions and Answers

Question 1.
How did the idea of sub-atomic particles evolve?
Answer:

• According to Dalton, atom is indivisible.
• But Michael Faraday’s experiments on electrolysis proved that atoms were acquiring negative charge during electrolysis.
• This is contradiction to Dalton’s theory.
• This lead to an idea that there must exist some tiny particles in atom which are responsible for atom to behave sometimes as charged particles.
• As atom is considered as electrically neutral, it probably had equal number of positive and negative constituents to maintain electrical neutrality.
• This gave scope to think about sub-atomic particles.

Question 2.
How do we determine the atomic mass of an element with its isotopes?
Answer:

• In nature, most elements occur as a mixture of two or more isotopes, each isotope has a certain percentage of natural occurrence.
• The atomic mass of an element is taken as an average mass of all the naturally occuring atoms of the sample element.
  Ex : Let us calculate the atomic mass of chlorine.
• Isotope of Cl occurs in nature, in two isotopic forms, with masses 35 units and 37 units.
• The isotope with mass 35 is present in 75% in nature.
• The isotope with mass 37 is present in 25% in nature.
• The average mass of chlorine is
  

Question 3.
Describe the Rutherford’s alpha particle scattering experiment. What are the conclu¬sions of this experiment.
Answer:

Rutherford conducted alpha particle scattering experiment in 1909 to study the atom.

1. The stream of alpha particles from a source having considerable energy is directed towards a very thin gold foil.
2. The gold foil was placed inside a detector in such a way that the detector would show a flash of light when an alpha particle struck it.
3. The entire arrangement was kept in a vacuum chamber.
4. Rutherford did not expect to see large deflections of alpha particles based on Thomson’s model.
5. But Rutherford observed the deflection of alpha particles through very large angles and a few alpha particles were reflected right back.
6. From this observation, Rutherford concluded as follows.

Conclusions :

1. Most of the space inside the atom is empty.
2. All the positive charge must be concentrated in a very small space within the atom and he named it as ‘nucleus’.

Question 4.
What information do you know from \({ }_{17}^{35} \mathrm{X}\)?
Answer:
Given that \({ }_{17}^{35} \mathrm{X}\)
a) The atomic number of element is 17.
b) Hence the element is chlorine, symbol is ‘Cl’.
c) Number of protons = 17.
d) Number of electrons = 17.
e) Mass number = 35.
f) Number of neutrons = 35-17 = 18
g) Distribution of electrons in shells

h) Valency is ‘l’.
i) It gains one electron to become octet.

SCERT AP 7th Class English Textbook Answers 2nd Lesson The Turning Point Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 2 Questions and Answers The Turning Point

7th Class English Unit 2 The Turning Point Textbook Questions and Answers

Observe the following picture and respond.

Question 1.
Guess the characters in the picture.
Answer:
The characters in the picture are a wise man and common man.

Question 2.
How do you think are they related to each other?
Answer:
The man with beard was a guru and the other man was a disciple.

Question 3.
Why did the young man meet the other person?
Answer:
The young man met the other person to take his advice.

Question 4.
What is the man with a beard saying?
Answer:
The man with a beard is saying something good.

Question 5.
Why do we listen to persons?
Answer:
We listen to persons to get good advice out of their experience.

Questions Given in the Lesson

Possible answers to the questions given in the middle of the lesson :

Question 1.
Who is your favourite teacher? What do you like about him/her? Which topic fascinated you the most in his/her class?
Answer:
Our science teacher is my favourite teacher.! like her way of explaining things and her way of treating the children. Almost all the topics taught by her fascinate me the most.

Question 2.
What do you want to become in your life?
Answer:
I want to become a doctor/an engineer/a teacher in my life.

Question 3.
How do you feel when you see birds flying in groups?
Answer:
It is really a wonderful sight to see. I feel thrilled at the sight of the birds’ flight in groups.

Reading Comprehension

A. Answer the following questions.

Question 1.
Why did Kalam take up the job as a newspaper boy?
Answer:
At the time of the Second World War, all the resources were scarce and the prices were not affordable. So, Kalam took up the job as a newspaper boy.

Question 2.
What was Kalam curious about?
Answer:
Kalam was curious about planes. He wanted to be a pilot himself.

Question 3.
Which topic did Shri Siva Subrahmania Iyer discuss one day in the class?
Answer:
The topic that Shri Siva Subrahmania Iyer discussed one day in the class was ‘how birds fly’.

Question 4.
Where did the teacher take the whole class to explain the concept of bird’s flight?
Answer:
The teacher took the whole class to the seashore to explain the concept of bird’s flight.

Question 5.
What was the turning point in Kalam’s life? Explain.
Answer:
The Kalam teacher’s lesson on bird’s flight was the turning point in his life.

Question 6.
When was Kalam honoured with the Bharat Ratna?
Answer:
In 1997, Kalam was honoured with the highest civilian award the Bharat Ratna.

B. Arrange the following sentences in the order they occurred in the story.

1. Abdul Kalam decided to study aeronautical engineering.
2. The photos of fighter aircrafts and the stories of the Second World War caught my attention.
3. In 2002 he was elected the 11th President of India.
4. Siva Subrahmania Iyer took the whole class to the seashore.
5. Kalam felt what he had learnt that day changed his life.
Answer:
2. The photos of fighter air crafts and the stories of the Second World War caught my attention.
4. Siva Subrahmania Iyer took the whole class to the seashore.
5. Kalam felt what he had learnt that day changed his life.
1. Abdul Kalam decided to study aeronautical engineering.
3. In 2002 he was elected the 11th President of India.

C. Read the following statements. Answer ‘True’ (T) or ‘False’ (F).
1. Sri Siva Subramania Iyer, sowed the seeds of vision.
2. One day Kalam taught about the bird’s flight.
3. Sri Subramania Iyer took the students to the airport to show the flying of aeroplanes.
4. Sri Kalam took up computer engineering at Madras institute of Technology
5. Sri Subramania Iyer ignited young minds.
Answer:

1. True
   False
2. False
3. False
4. True

Correct the false statements and rewrite them in the space provided.
Answer:
2. One day Kalam was taught about the bird’s flight.
3. Sri Subramania Iyer took the students to the seashore to show the flying of birds.
4. Sri Kalam took up aeronautical engineering at IIT, Madras.

Vocabulary

A. Other forms of the words
Read the following sentences from the text.

1. The prices were not affordable.
2. It was usually filled with the photos of fighter aircrafts.

Look at the underlined words in the above sentences. The word ‘affordable’ comes from the root word ‘afford’ and the word ‘usually’ comes from the root word ‘usual.’

Identify’ the other forms of the following words used in the lesson ‘The Turning Point’.

Answer:

B. Compound Adjectives

Read the following sentences.

My curiosity was fulfilled by a very special teacher when I was a ten-year-old boy in Class V. This was indeed a life-changing event.

In the above sentence the words “ten”, “year” and “old” and “life” and “ changing” are combined using a hyphen (-) and is made into a single adjective called compound adjective. Compound adjectives can be formed by bringing two different words to¬gether with a hyphen.

E.g. five-day, smart-looking, old-fashioned, short-haired

Match the following words in Set -A with Set – B to make coi lpound adjectives and write them in the space given.

Set-A	Set-B	Compound Adjective
absent	aged	absent-minded
middle	hearted	middle-aged
well	behaved	well-behaved
brand	minded	brand-new
kind	new	kind-hearted

Fill in the blanks with the compound adjectives you have made.

1. Kalarn was one of the ………….. boys in his class.
2. The ………… girl helped the old man to cross the road.
3. Mohan who is an ………… person, forgot his wallet at the cash counter.
4. Murali bought a …………. car.
5. The ………… man who is standing at the gate, is my uncle.
Answer:

1. well-behaved
2. kind-hearted
3. absent-minded
4. brand-new
5. middle-aged

C. Compound Words

When you read the lesson ‘The Turning Point’ you might have come across the following words.

“newspaper”, “seashore”,” sunset”

These words are formed when two or more words are joined together to create a new word, that has entirely new meaning.

Try and make compound words with the following words. You are free to add a word either to the left or right of the given words. One is done for you.

E.g.: House – housekeeper, storehouse
1. Hand 2. Room 3. Pot 4. Butter 5. Box
Answer:
1) hand : handmade, firsthand, handshake, handprint, handicraft
2) room : roommate, classroom, bedroom .
3) pot : pothole, teapot, inkpot, pothead, potluck
4) butter : buttermilk, butterfish, peanut butter
5) box : gearbox, toolbox, mailbox

Make more compound words and have fun.

Compound Words:
bedroom, airport, anybody, backbone, background, cardboard, commonwealth, daybreak, earthquake, fireproof, grandchildren, headache, inside, jackpot, keyboard, layout, moonlight, newsreader, overcoat, passbook, playground, scarecrow, talebearer, understimate, warehouse, etc.

Fill in the blanks with a suitable word from the help box to make a compound word. One is done for you.
E.g. moon light house
(Moonlight and lighthouse are two different compound words with the same word ‘light’.)

Help Box
light
cover
sugar
fisher
land
paper
1. Cane sugar candy
2. News paper bag
3. Pillow cover story
4. King fisher man
5. Grass land mark
Answer:
1) canesugar, sugarcandy
2) newspaper, paperbag
3) pillowcover, coverstory
4) kingfisher, fisherman
5) grassland, landmark

Grammar

The Present Perfect Tense vs The Simple Past Tense :
Look at the following sentences from the text.
1) That evening he took all of us to the seashore.
2) I chose physics.
3) This was indeed a life-changing event.
4) Kalam dedicated his achievements to all his teachers.

The above sentences denote the actions completed in the past. Hence, the verb is in simple past tense.

Identify at least five verb forms used in the simple past tense from the text.
Answer:

1. caught (Irregular Verb)
2. manoevured (Regular Verb)
3. belonged (Regular Verb)
4. grew (Irregular Verb)
5. drew (Irregular Verb) 6. explained (Regular Verb)
6. understood (Irregular Verb)
7. asked (Regular Verb)
8. needed (Regular Verb) 10. opted (Regular Verb)

Exercise – 1

Fill in the blanks with past form of the verb given in brackets.

1. Sankar …………… (join) the bank last month.
2. Where …………… (be) you yesterday?
3. Fathima …………… (pass) the intermediate exam in 2016.
4. Indian Cricket team …………… (win) the trophy in 2017.
5. Leena …………… (write) her examinations and …………… (go) home immediately.
Answer:

1. joined
2. were
3. passed
4. won
5. wrote, went

Already we have discussed ‘present perfect tense’ in unit-1.

Present perfect tense denotes the action that began in the past and continuous to the present time.

We write present perfect tense with the markers like ‘just, yet, etc. (adverbs of time).

We write past tense with the markers like yesterday, last week/month/…, ago, etc.

Exercise – 2

Adverbs of time used with present perfect tense

Fill in the blanks with Adverbs of Time :
1. Is Mr. Ravi at home?
No, he …………… left for work.

2. When does the train to Kakinada arrive?
It has …………… left.

3. The Chief Guest hasn’t arrived …………… .
4. I have lived in Vijayawada …………… a long time.
5. I have lived in Delhi …………… 2004.
6. Have you been to a circus?
Answer:
1. Is Mr. Ravi at home?
No, he already left for work.

2. When does the train to Kakinada arrive?
It has just left.

3. The Chief Guest hasn’t arrived yet.
4. I have lived in Vijayawada for a long time.
5. I have lived in Delhi since 2004.
6. Have you ever been to a circus?

Writing

A. You have read the text ‘The Turning Point’. The stories of the World War and the inspiring teachings of his teacher Sri Siva Subramania Iyer acted as a turning point of Kalam’s life.
Now prepare a script for a speech on the turning point in the life of Abdul Kalam and present it on the Teachers’ Day in your school.
Answer:
Respected Headmaster, teachers and other staff, Happy Teachers’ Day to all of you. It is a great privilege for me to be here to speak about the turning point in Kalam’s life.

A.P.J. Abdul Kalam always used to say he would like to be remembered as a teacher. When he became the President in 2002, he made no compromise on his passion for teaching. He grabbed every opportunity to teach students, especially children, wherever he went.

His curiosity grew in science because of a very special teacher, when he was a ten- year-old boy in Class V. This was indeed a life-changing event. His science teacher’s name was Shri Siva Subramania Iyer. One day the topic of discussion in his class of sixty-five was ‘how birds fly’. He drew a sketch of a bird with a tail, wings and feathers a head on the board and explained how a bird flew.

That evening he took all of them to the seashore. He asked all of them to notice how the birds make a formation in a group and fly. Mr. Iyer also made them notice how the bird is powered to fly by itself.

The flight principle got imprinted in Kalam’s mind and he decided that in the future he would study subjects related to flight. However, as a little boy he needed guidance to pursue that field. The teacher told Kalam to study and explore the field of aviation .science and aeroplanes.

Whatever he had learnt that day changed his life. He was inspired to have an aim. Later he realized how important it was to study physics. He chose physics. He opted for aeronautical engineering at the Indian Institute of Technology, Madras. Then, he became an aeronautical engineer and a space technologist. Mr. Iyer’s class had transformed his life which led him to make a profession out of his passion and his career began in that field.

We have to take Kalam’s life as an inspiration to grow high in our lives.

Thank you very much for giving me this opportunity.

B. Prepare a biographical sketch of Sri APJ Abdul Kalam using the given information.

Birth : 15 Oct 1931 at Dhariushkodi, Rameswaram, Tamil Nadu.

First job : Newspaper vendor

Inspiration : His Science teacher Sri Siva Subramania Iyer’s lecture

Education : Aeronautical Engineering from IIT(M) ( 1960)

Positions : IGMDP, DRDO, ISRO – Chief Advisor and Chairman

Achievements : Project Devil and Project Valiant (1970)
SLV – III, ROHINI, PSLV, PRUTHVI & AGNI Missiles, Nuclear Test. -Pokhran -II

Invented ‘Low Cost Coronary Stent’ and Rugged Tablet Computer with Dr. Soma Raju (1998)

Unanimously elected as the President of India (2002 – 2007) ‘People’s President.
Literary Works : Wrote ‘Wings of Fire’, ‘Ignited Minds,’ etc.

Awards : Honoured with Padma Bhushan (1981), Padma Vibhushan (1990) and Bharath Ratna(1997)
Death : 27 July 2015

Answer:
A.P.J. Abdul Kalam was born on 15th October 1931 at Dhanushkodi, Rameswaram, Tamil Nadu. In his childhood he worked as a newspaper vendor. His Science teacher Shri Siva Subrahmania Iyer’s lecture inspired him a lot. He completed Aeronautical Engineering from IIT(M) ( 1960) He held the position of the Chief Advisor and Chair¬man ot IGMDPV DRDO, ISRO. He was responsible for Project Devil and Project Valiant (1970), SLV – III, ROHINI, PSLV, PRUDVI & AGNI Missiles, Nuclear Test at Pokhran -II. He invented ‘Low Cost Coronary Stent’ and Rugged Tablet Computer with Dr. Soma Raju (1998). He was unanimously elected the presedent of India (2002 – 2007) . He was known as ‘People’s President. He wrote ‘Wings of Fire’ and ‘Ignited Minds. He was honoured with the Padma Bhushan (1981), the Padma Vibhushan (1990) and the Bharath Ratna (1997). He passed away on 27 July 2015.

Fun Time

Try the following riddle.
The three-letter word that reads the same backwards : eye (a part of the body)

Read the following ‘Palindrome’.

1. Race car
2. Madam
3. Don’t nod
4. Dogma I am God
5. Never odd or even
6. Madam I’m Adam
7. Too bad I hid a boot

Talking Time

A. Making Announcements:

Read the announcements usually made during the school assembly.

Dear Students, I have an announcement to make. We are planning to conduct sports and literary competitions on the occasion of Independence Day. The students those who want to participate in the sports competitions have to give their names to the Physical Director of our school. Those who want to participate in the literary competitions have to give their names to the English teacher.

You are the secretary of your school English Club. Make an announcement for the activities to be planned for the English Day.
Answer:
Dear Students, I have an announcement to make. We are planning to conduct a quiz and literary competitions on the occasion of the English Day. The students those who want to participate in the quiz competition have to give their names to Biology teacher of our school. Those who want to participate in the literary competitions have to give their names to the English teacher.

B. Role-play:

Polite Request : (Could you please / Would you mind)
Srikar : Excuse me, could you please tell me when the Tirumala Express leaves for Vizag?
Enquiry : It starts at 5.05 p.m. every day.
Srikar : Could you please tell me the time of arrival at Vizag ?.
Enquiry : It reaches Vizag at 11 a.m. the next day.
Srikar : Thank you. Would you mind telling me if the tickets are available for tomorrow?
Enquiry : Let me check. Sorry. No tickets are available until next Sunday.
Srikar : OK, thank you, Sir. I’ll plan my journey accordingly.
Enquiry : You are welcome.

Language focus
1. Could you please ………………………
Eg : Could you please give me your pen?

2. Would you mind ……………………..
Eg : Would you mind opening the window? / Could you open the window?

Exercise – A

Underline the correct expression to complete each request.
1. Could you / Would you mind bringing me some milk for my coffee?
2. Could you / Would you mind answering the question?
3. Could you / Would you go to the shop for me?
4. Could you / Would you mind turning off the music?
5. Could you / Would you mind bringing me a glass of banana juice?
Answer:

1. Could you / Would you mind bringing me some milk for my coffee?
2. Could you / Would you mind answering the question?
3. Could you / Would you go to the shop for me?
4. Could you / Would you mind turning off the music?
5. Could you / Would you mind bringing me a glass of banana juice?

Exercise – B

Complete the polite requests with the correct forms of the verb in brackets.
1. Could you …………… (bring) me a cup of coffee?
2. Could you …………… (lend) me your pen?
3. Would you mind …………… (call) a taxi for me?
4. Would you mind …………… (close) the door?
5. Could you …………… (get) me a glass of water?
6. Would you mind …………… (carry) these bags for me?
Answers

1. bring
2. lend
3. calling
4. closing
5. get
6. carrying

Listening

Transformation of Vivekananda

The relationship between Sri Ramakrishna and Vivekananda (formerly named as Narendranath) began in November 1881 when they met at the house of Surendranath Mitra. Ramakrishna had asked Narendranath to sing. He was impressed with the sing¬ing talent of Narendranath and invited him to Dakshineswar.

Narendra accepted the invitation. The meeting with Sri Ramakrishna proved to be a turning point in the life of Narendranath. Initially, he did not accept Ramakrishna as his master. But eventually, he became one of the closest disciples of-Ramakrishna who shaped the personality of Narendranath and inspired him to dedicate his life to serve the human.

Inspired by Ramakrishna, Narendranath became a monk and was named Vivekananda and he presented a speech at the Parliament of the World’s Religions held on 23rd September, 1893 in Chicago.

His meeting with Sri Ramakrishna in Dakshineswar was a turning point which re-sulted in the transformation of Vivekananda.

A. Listen to the story and state the following statements are true / false.
1. The meeting with Sri Ramakrishna was the turning point in the life of Vivekananda.
2. Sri Ramakrishna presented a speech in Chicago.
3. Sri Ramakrishna and Vivekananda first met at the house of Surendranath Mitra.
Answer:

1. True
2. False
3. True

Comprehension

1. Why did Ramakrishna invite Narendranath to Dakshineswar?
Answer:
Sri Rafnakrishna was impressed with the singing talent of Narendranath and he invited him to Daksineswar.

2. How did Ramakrishna inspire Narendranath?
Answer:
Ramakrishna inspired Narendranath by his wisdom.

3. Where did Vivekananda present his speech?
Answer:
Vivekananda presented his speech in Chicago.

4. What did Vivekananda dedicate his life to?
Answer:
Vivekananda dedicated his life to serve the human.

5. Do you believe in transformation of yourself?
Answer:
Yes.

Study Skill

Study the following Tree diagram.

Answer the following questions :

1. What is the tree diagram about?
Answer:
The tree diagram is about the things in our sufroundings.

2. What are the two kinds of animals mentioned in the above tree diagram?
Answer:
Living things and Non-living things.

3. Things in our surroundings are categorised into _________ .
a) 3
b) 2
c) 4
Answer:
b) 2

4. ‘Viviparous’ is a category of _________ .
a) Plants
b) Oviparous
c) Animals
Answer:
c) Animals

5. ‘Plants and animals’ come under _________ .
a) Living things
b) Oviparous
c) Non-living things
Answer:
a) Living things

The Turning Point Summary

The Turning Point’, is an edited extract from ‘My Teachers’ by DR A.P.J. ABDUL KALAM. The turning point means- An important change in the life of a person. This is the true story of Abdul Kalam that made a turning point in his life. When he was in class V, one day his teacher Shri Siva Subramania Iyer taught him about a bird’s flight in the class. When the teacher explained in the class about a bird’s flight most of the students including Kalam had not understood the lesson. So the teacher took them all to the seashore of Rameswaram (birthplace of Kalam) to teach them practically. The teacher showed there how a bird flies. He asked the students to look at the tail and the combination of flapping wings and twisting tail. The teacher explained how the birds changed direction, and position could fly in the direction they wanted to. After that all the students understood the lesson of a bird’s flight. For Kalam the lesson was not merely an understanding of how a bird flies. He decided that he wanted to study all he could about the concept of flight. So he took his teacher’s advice about the further study of Science. He became a rocket engineer, an aerospace engineer and a technolo¬gist. But the memory of his teacher encouraging him to become a successful person was up to the end of Kalam’s life.

The Turning About the Author

Avul Pakir Jainulabdeen Abdul Kalam was an Indian aerospace scientist and a politician who had served as the 11th President of India from 2002 to 2007. He was born on the 15th of October, 1931 at Dhanushkodi, Rameswaram, Tamil Nadu. He is popularly known as the Missile Man of India. His book Wings of Fire’ is widely read and is inspiring. This lesson is an extract from his book My Teachers’.

Meanings For Difficult Words

turning point (n) : a time at which an important change takes place
conflict (n) : clash, a serious disagreement
scarce (adj) : rare
affordable (adj) : reasonably priced
defend (v) : protect
manoeuvred (v) : plotted / steered / moved skillfully
curiosity (n) : a strong desire to know
gloomy (adj) : unhappy
flap (v) : move up and down
generate (v) : produce or create
unique (adj) : matchless/special
transform (v) : change
passion (n) : strong desire
indigenous (adj) : native, local
ignite (v) : light, kindle

Give Me Strength Poem

This is my prayer to thee, My Lord – strike,
strike at the root of penury in my heart.
Give me the strength lightly to bear my joys and sorrows.
Give me the strength to make my love fruitful in service.
Give me the strength never to disown the poor or bend my knees before insolent might.

Give me the strength to raise my mind high above daily trifles.
And give me the strength to surrender my strength to thy will with love.
Rabindranath Tagore

Appreciation of The Poem

A. Answer the following questions :

Question 1.
What does the poet pray for?
Answer:
The poet prays to God for giving him strength.

Question 2.
What does the poet want to bear with strength?
Answer:
The poet wants to bear joys and sorrows with strength.

Question 3.
Wteafcitype of service does the poet want to make?
Answer:
He wants to be in the service of humankind with sincerity and humility.

Question 4.
How does the poet want to treat the poor and the mighty?
Answer:
He wants to help the poor and never to bend before rude and disrespectful authority.

Question 5.
What does the poet want to do with the strength finally?
Answer:
He wants to raise his head above petty and ordinary things and surrender his strength before the will of God.

Additional Questions

Question 1.
Why does the poet want God to strike at his heart?
Answer:
The poet implores God to strike at his heart to remove the hardheartedness and remake it with love and compassion. He wants to be a loving and caring human beings.

Question 2.
What does the poet want the strength for?
Answer:
The poet wants strength to bear joys and sorrows. He wants strength to make his love fruitful in service. He needs strength never to disown the poor or bow before a tyrant. Moreover, the poet needs strength to avoid the daily trifles and submit his will to the will of God.

Question 3.
How can love be made meaningful in one’s life?
Answer:
Love is meaningful when it bears fruits of service, service of mankind.

Question 4.
What should be our attitude towards the poor?
Answer:
Our attitude towards the poor should be very sympathetic. We should never disown or neglect them. We should always help the poor and work for their welfare.

Question 5.
What does “bend my knees” signify?
Answer:
The bending of one’s knees means to surrender before a powerful person. Here, the poet prays to God to give him the strength to resist and not to bend the knees before a tyrant.

Question 6.
Why does the poet want to raise his mind high above “daily trifles”?
Answer:
The poet wants to raise his mind high above the daily trifles so that he would not be involved in the issues that fill his heart with malice and prejudice.

Question 7.
Why does the poet ask for strength to surrender his will to God’s will?
Answer:
The poet wants to surrender his will to the will of God in order to live a pure and obedient life. As it is not easy to submit one’s will, the poet prays for the strength to do so.

B. Choose the right option and write it in the brackets given.

1. Strike at the root of _____ in my heart.
a) treasury
b) happiness
c) penury
Answer:
c) penury

2. Give me strength to bear my _____
a) riches and treasures
b) joys and sorrows
c) property
Answer:
b) joys and sorrows

3. Give me strength to make my love _____ in service.
a) fruitful
b) selfish
c) sacrifice
Answer:
a) fruitful

4. Give me strength to raise high above daily _____
a) enjoyment
b) trifles
c) chores
Answer:
b) trifles

5. The poet wants to surrender his strength to _____
a) the mighty
b) God’s will
c) the poor
Answer:
b) God’s will

Check Point

Give Me Strength Summary

“Give Me Strength” is an inspirational poem by the versatile Rabindranath Tagore. The poem is in a form of a prayer and the poet is asking the Lord to provide him with strength so that he can overcome all the hurdles in life.

This poem “Give Me Strength” is short but beautiful poem written by Rabindranath Tagore. In this poem, the poet prays to God to strike at the core of his heart and remove the ignorance from there. He prays to God to give him strength so that he bears the joys and sorrows of life in the same spirit. It means that the poet wants to be stoic in his nature. He wants to be in the service of humankind with sincerity and humility. He wants to help the poor and never to bend before rude and disrespectful authority. He also prays for strength to raise his head above petty and ordinary things and surrender his strength before the will of God.

Give Me Strength About the Poet

Rabindranath Tagore (7 May 1861 – 7 August 1941) usually called Gurudev was a learned man from West Bengal from the Indian sub continent. He was a poet, musician and artist. He reshaped Bengali literature and music. He is the author of the Gitanjali, which is a collection of beautiful verse. He was the first Indian to win the Nobel Prize in literature in 1913. Tagore’s poetry is viewed as spiritual and patriotic. He was referred to as ‘the Bard of Bengal’.

Meanings for Difficult Words

Thee (n) : you
strike (v) : hit forcibly
penury (n) : extreme poverty; (here) hardheartedness, lacking love and compassion
fruitful (adj) : bearing abundant fruit; producing results
disown (v) : not own / refuse
insolent (adj) : disrespectful, rude
might (n) : power / impressive power.
trifles (n) : things of little value or significance
surrender (v) : yield; give up.
thy (pron.) : your (old use)

AP State Syllabus AP Board 9th Class Physical Science Important Questions Chapter 6 Chemical Reactions and Equations

AP State Syllabus 9th Class Physical Science Important Questions 6th Lesson Chemical Reactions and Equations

9th Class Physical Science6th Lesson Chemical Reactions and Equations 1 Mark Important Questions and Answers

Question 1.
Fe₂O₃ + 2 Al → Al₂O₃ + 2Fe
Name the compound which is oxidized in the above reaction.
Answer:
In the reaction Fe₂O₃ + 2Al → Al₂O₃ + 2Fe,
Aluminium (Al) is oxidised and formed as Al₂O₃.

Question 2.
Give an example for displacement reaction.
Answer:
1) In displacement reaction one element displaces another element from its compound and takes its place there in.

2) Eg : Zinc pieces react with dilute hydrochloric acid and liberate Hydrogen gas.
Zn_(s)+ 2HCl_(aq) → ZnCl_2(aq) + H_2(g)

Question 3.
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Assume and write the name of the element ‘X’ and also predict the substance formed black in colour.
Answer:
Element X – Copper.
Black substance – Copper Oxide

Question 4.
Iron gets rust but Gold doesn’t, why?
Answer:
Gold does not oxidized.
(OR)
Gold is least reactive metal.

Question 5.
What happens if iron articles are exposed to moist air? Write the chemical equation to represent that reaction.
Answer:
Rusting takes place on iron articles when they are exposed to moist air.
2Fe_(s) + O_2(g) + 4H⁺_(aq) → 2Fe²⁺_(aq) + 2H₂O_(l)

Question 6.
On adding dilute hydrochloric acid to copper oxide powder, the solution formed is blue green. Write the new compound formed.
Answer:
Copper oxide reacts with hydrochloric acid and forms copper chloride and water. Copper chloride is in blue green colour.
CuO + 2 HCl → CuCl₂ + H₂O

Question 7.
Write the equation for the chemical decomposition reaction of silver chloride in the presence of sunlight.
Answer:

Question 8.
Balance the following chemical equation.
Na + H₂O → NaOH + H₂
Answer:
2Na + 2H₂O → 2NaOH + H₂

Question 9.
If you keep an iron piece in solid state CuSO₄ crystals, does it get any reaction? Guess the reason.
Answer:
Reaction will not takes place if an iron piece is placed in solid state CuSO₄ crystals because there will not exist separate Cu⁺², SO₄^-2 ions in CuSO₄ Crystals. In aqueous solution, they exists. So iron can not displace copper.

Question 10.
What is a chemical equation?
Answer:
Chemical Equation :
Describing a chemical reaction using least possible words or symbols is called a chemical equation.
Ex : CaO + H₂O → Ca(OH)₂

Question 11.
What are “Reactants” and “Products”?
Answer:
1) Reactants :
The substances which undergo chemical change in the reaction are called ‘Reactants’.

2) Products:
The new substances formed in a chemical reaction are called ‘Products’.
Ex : Zn + 2HCl → ZnCl₂ + H₂ ↑
3) In above reaction Zn and 2HCl are called reactants, ZnCl₂ and H₂ are called products.

Question 12.
What is a balanced chemical equation?
Answer:
Balanced Chemical Equation :
A chemical reaction in which the number of atoms of different elements on the reactants side (left side) are same as those on product side (right side) is called a balanced chemical equation.
Ex : Mg + O₂ → MgO (Unbalanced chemical equation)
2 Mg + O₂ → MgO (Balanced chemical equation)

Question 13.
What is chemical change?
Answer:
Chemical Change :
The process in which the change is affecting the identity of a molecule by a change in chemical composition is called a “chemical change”.

Question 14.
What is physical change?
Answer:
Physical Change: The process where a change is occurring only in physical properties, without affecting the identity of the molecules is called a “physical change”.

Question 15.
What is the meaning of “Exo”, “Endo” and “Thermo”?
Answer:
The term ‘Exo’ means outside, ‘Endo’ means inside and ‘Thermo’ means heat.

Question 16.
What is oxidation? Give examples.
Answer:
Oxidation is a reaction that involves the addition of oxygen or loss of hydrogen or electrons.

Question 17.
What is a reduction? Give examples.
Answer:
The process in which a substance loses oxygen or gains hydrogen or electrons is known as reduction.

Question 18.
What is corrosion?
Answer:
Corrosion :
When some metals are exposed to moisture, acids etc. they tarnish due to the formation of respective metal oxide on their surface. This process is called “corrosion”.

Question 19.
What is “galvanizing”?
Answer:
It is a method of protecting iron from rusting by coating them a thin layer of zinc.

Question 20.
What is combustion?
Answer:
The process of burning a substance in the presence of oxygen is called “combustion”.

Question 21.
What do you mean by “rancidity”?
Answer:
Food materials containing fat / oil are exposed to air, for a long time they react with atmospheric oxygen and it is responsible for spoiling of food. This process is called “rancidity”.

Question 22.
How do you know that respiration is an exothermic reaction?
Answer:
During the respiration reaction energy releases, so it is an exothermic reaction.

Question 23.
What will happen in chemical reaction?
Answer:
New substances are formed in chemical reaction.

Question 24.
What is precipitate?
Answer:
A precipitate is a solid product’ which separates out from the solution during a chemical reaction.

Question 25.
How does precipitation reaction occur? Explain with an example.
Answer:

1. Prepare lead nitrate and potassium iodide solutions in separate test tubes.
2. Mix the two solutions.
3. A yellow colour substance which is insoluble in water, is formed. This insoluble substance is known as precipitate. The precipitate here in this reaction is lead iodide.
   Pb(NO₃)₂ + 2KI → Pbl₂ + 2KNO₃

Question 26.
What is a balanced chemical equation?
Answer:
A balanced chemical equation has an equal number of atoms of different elements in the reactants and products.

Question 27.
What is an unbalanced equation?
Answer:
An unbalanced chemical equation has an unequal number of atoms of one or more elements in the reactants and products.

Question 28.
Why do the smell and taste of food items change?
Answer:
When fats and oils are oxidized they become rancid. So their smell and taste change.

Question 29.
“Freshly cut apple turning brown, the iron articles shiny when new, but gradually become reddish brown when left for sometime ………”. How do these changes occur?
Answer:
Oxygen molecules interact with different substance from metal to living tissue which may come into contact with it. The above changes occur. These are all the examples of the process of oxidation.

Question 30.
What are antioxidants?
Answer:
Antioxidants :
The spoilage of food can be prevented by adding preservatives which prevent oxidation. The substances which prevent oxidation are called antioxidants.
(OR)
The substances which prevent oxidation added to food containing fats and oil are called antioxidants.

Question 31.
Complete the following reaction.
Pb(NO₃)₂ + 2 KI → …………….. + …………………
Answer:
Pb(NO₃)₂ + 2 KI → Pbl₂ + 2KNO₃

Question 32.
If iron nail is dipped in copper sulphate solution, after sometime copper will be formed. Write the chemical equation for this reaction.
Answer:
Fe + CuSO₄ → FeSO₄ + Cu

Question 33.
Which metal is used in the manufacture of Diwali crackers?
Answer:
The metal used in manufacture of Diwali crackers is Magnesium.

Question 34.
What are new substances formed due to decomposition of lead nitrate?
Answer:
The new substances formed are lead oxide, nitrogen dioxide and oxygen.

Question 35.
Balance the following chemical equation. C₂H₆ + O₂ → CO₂ + H₂O
Answer:
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Question 36.
NH₄Cl → NH₃ + HCl. Which type of reaction is this?
Answer:
This is decomposition reaction.

Question 37.
Which chemical reaction is involved in the corrosion of iron?
Answer:
The chemical reaction involved in corrosion of iron is oxidation reaction.

Question 38.
Which metal is used for wrapping food material? Why?
Answer:
Aluminium is used to wrap food material because it reacts with oxygen and forms a protective layer of aluminium oxide which prevents further oxidation.

Question 39.
Write states of the reactants and products and also write conditions required for the completion of reaction.
Answer:
2H₂O → 2H₂ + O₂
H₂O is in liquid state. H₂ and 0₂ are in gaseous state.
The reaction is carried out in the presence of electricity.

Question 40.
Give an example for chemical combination reaction where only elements take part.
Answer:
2 H₂ + O₂ → 2H₂O
Here hydrogen and oxygen both are elements.

Question 41.
Give an example for chemical combination where element and compound take part in the reaction.
Answer:
2 NaN02 + O₂ → 2 NaNO₃
Here O₂ is element and NaNO₂ is compound.

Question 42.
Give an example where two compounds combine together to form a compound.
Answer:
CaO + H₂O → Ca(OH)₂
Here both calcium oxide, water are compounds which combine together to form calcium hydroxide.

Question 43.
Before burning in air, why is Mg ribbon cleaned by rubbing with a sand paper?
Answer:
To remove the protection layer of basic magnesium carbonate from the surface of magnesium

Question 44.
X Pb(NO₃)₂ → Y PbO + Z NO₂ + W O₂.
If the equation is a balanced equation, what are values of coefficients X, Y, Z and W?
Answer:
The balanced equation is 2 Pb(NO₃)₂ → 2 PbO + 4 NO₂ + O₂.
∴ The values are X = 2,Y = 2, Z = 4 and W = 1.

Question 45.
Why does a layer of zinc prevent rusting of iron?
Answer:
Zinc reacts with oxygen and forms layer of zinc oxide which prevents further oxidation. So a layer of zinc protects iron from rusting.

Question 46.
Why does jewellery made of gold not rust?
Answer:
Gold does not react with air because it has least reactivity. So gold jewellery does not rust.

Question 47.

What type of reaction is this? Which element between A and C is more reactive? Why?
Answer:
This reaction is chemical displacement. ‘C’ is more reactive than ‘A’. So C displaces ‘A’ from AB and occupies its place.

Question 48.
Given AB + CD → AD + CB. What type of chemical reaction is this? What is the condition which makes the reaction possible?
Answer:
This is double displacement reaction. This reaction can be possible if ionisation of both the salt solutions are possible.
i.e., AB → A⁺ + B^–
CD → C⁺ + D^–

Question 49.
An iron nail is completely immersed in a test tube containing oil. Do you observe any rust on the iron nail? If not, why?
Answer:
No, I do not observe any rust because both air and moisture are required for rusting of iron.

Question 50.
How can we prevent rusting of iron?
Answer:
Rusting of iron can be prevented or at least minimised by shielding the metal surface from oxygen and moisture. It can be prevented by painting, oiling, greasing, galvanizing, chrome plating or making alloys.

Question 51.
Suggest few methods to avoid corrosion.
Answer:
Some methods to avoid corrosion

1. Painting, oiling, greasing on the surfaces of the metals.
2. Galvanizing the metal with thin layer of zinc.
3. Making alloy metals prevents corrosion,
   eg : brass, bronze and steel.

Question 52.
Some metals react with oxygen to form their oxides. It is serious problem. Give some examples for oxidation of metals and write balanced equations.
Answer:
1) Iron reacts with oxygen and forms iron oxide.
4Fe + 3O₂ → 2Fe₂O₃.

2) Copper reacts with oxygen and forms copper oxide.
2Cu + O₂ → 2CuO

3) Silver tarnishes when reacts with hydrogen sulphide and oxygen
4Ag + 2H₂S + O₂ → 2Ag₂S + 2H₂O

Question 53.
Which pipes are suggestable/suitable for water supply? Justify your answer.
Answer:
Steel, PVC and CPVC pipes are suitable/suggestable for water supply.
Reasons:

1. They are not oxidised in moisture.
2. They do not form oxides.
3. They are not corroded.
4. So, they are durable and safe to use in supply of water.

Question 54.
Which pipes are used by you for water supply to your house?
Answer:

1. PVC, CPVC and steel pipes are used for water supply in my house.
2. Because they do not corrode.

Question 55.
List of metals are given below. Classify them into corroded and non-corroded metals. Aluminium, Silver, Iroh, Copper, Gold, Tin, Tungsten, Platinum.
Answer:
Corroded metals :
Aluminium, Silver, Iron, Copper

Non-corroded metals :
Gold, Tin, Tungsten, Platinum.

9th Class Physical Science6th Lesson Chemical Reactions and Equations 2 Marks Important Questions and Answers

Question 1.
A light yellow coloured compound ‘X’ is exposed to sunlight for some time. It is turned into gray coloured material. What is the name of ‘X’? Predict the type of chemical reaction occured in it.
Answer:
1) The name of the compound ‘X’ is Silver Bromide (AgBr).

This is a decomposition reaction and also it occurs in the presence of sunlight. Hence, it is a photo chemical reaction.

Question 2.
Oil and fat containing food item packets are flushed with Nitrogen gas. Why?
Answer:
By stopping the oxidation it prevents the rancidity of food material.

Question 3.
N_2(g) + O_2(g) + heat → 2NO_(g)
What information do you get from the above equation? Comment.
Answer:

• Nitrogen gas reacts with oxygen gas in the presence of heat energy and forms nitric oxide gas.
• It is an endothermic reaction.
• This is an example for chemical combination reaction.
• In this reaction, the reactants are gases and products are also gases.

Question 4.
Write an activity about how you conduct an experiment to show that more reactive metals replace less reactive metals from their compounds.
Answer:

• Take two iron nails and clean then by rubbing with sand paper.
• Take two test tubes and mark them ‘A’ and ‘B’.
• Pour copper sulphate solution in the test tube ‘A’ and Zinc Chloride solution in the test tube ‘B’.
• Dip iron nails in both test tubes.
• Keep them without disturbing for 20 min.

Observation :

1. The nail which is dipped in Copper Sulphate solution becomes brownish colour.
2. The nail which is dipped in Zinc Chloride solution doesn’t change.

Reaction :
In test tube ‘A’: CuSO₄ + Fe → FeSO₄ + Cu
In test tube ‘B’: ZnCl₂ + Fe → No reaction.

Conclusion :

1. Iron is more reactive than copper. So it displaces copper from Copper Sulphate solution.
2. Iron is less reactive than zinc. So, it doesn’t displace zinc from ZnClr

Question 5.
i) CaCO_3(s) → CaO_(s) + CO_3(g)
ii) 2Ag Br_(s) → 2Ag_(s) + Br_2(g)
Mention the types of reactions to which the above equations belong. Also mention which of them is a photochemical reaction.
Answer:
1) i) CaCO_3(s) → CaO_(s) + CO_2(g). It is a chemical decomposition reaction.
ii) 2Ag Br_(s) → 2Ag_(s) + Br_2(g). It is also a chemical decomposition reaction.

2) 2Ag Br_(s) → 2Ag_(s) + Br_2(g). It is a photochemical reaction. Because, this reaction
takes place in the presence of sunlight only.

Question 6.
Write the products of given reactions, if any. Give reason.
FeCl₂ + Zn →
ZnCl₂ + Fe →
Answer:
FeCl₂ + Zn → ZnCl₂ + Fe (Displacement reaction)
ZnCl₂ + Fe → No reaction. (Low reactive metals cannot displace high reactive metals)

Question 7.
Balance the following chemical equations:
i) Na + H₂O → NaOH + H₂
ii) K₂CO₃ + HCl → KCl + H₂O + CO₂
Answer:
i) 2Na + 2H₂O → 2NaOH + H₂
ii) K₂CO₃ + 2HCl → 2KCl + H₂O + CO₂

Question 8.
Observe the following balanced chemical equation and answer the given questions.
C₃H_8(g) + 5O_2(g) → 3CO_2(g) + 4H₂O_(g)
i) How many molecules of Oxygen are involved in this chemical reaction?
ii) How many moles of Propane are required to get 20 moles of Water?
Answer:
i) In this chemical reaction five molecules of oxygen are involved.
ii) Five moles of propane are required to get 20 moles of water.

Question 9.
What do you do to prevent rusting of copper and silver articles?
Answer:
I can follow some rules given below to prevent rusting of copper and silver articles.

1. Shielding the metal surface from oxygen and moisture.
2. By painting.
3. By oiling, greasing.
4. By galvanizing, chrome plating.
5. By making alloys.

Question 10.
What are the important characteristics of chemical reactions?
Answer:
The important characteristics of chemical reactions are

1. Evolution of a gas
2. Formation of a precipitate
3. Change in colour
4. Change in temperature
5. Change in state

Question 11.
What symbols do we use to indicate the physical state of reactants and products in an equation?
Answer:

1. Solid state is indicated by the symbol (s)
2. Liquid state is indicated by the symbol (l)
3. Gaseous state is indicated by the symbol (g)
4. Aqueous solution is indicated by the symbol (aq)

Question 12.
What can we do to make a chemical equation more informative?
(OR)
How can chemical equation be made more informative by knowing?
Answer:

1. Physical state,
2. Heat changes (exothermic and endothermic reactions),
3. Gas evolved,
4. Precipitate formed.

Question 13.
Commemt on “C_(s) + O_2(g) → CO_2(g) + Heat” equation.
Answer:

• The burning of carbon in oxygen is an exothermic reaction because heat is evolved in this reaction.
• An exothermic reaction is indicated by writing + Heat or + Heat energy or just + Energy on the products side of an equation.

Question 14.
Comment on “N_2(g) + O_2(g) + Heat → 2 NO_(g)” equation.
Answer:

• The reaction between nitrogen and oxygen to form nitric oxide is an endothermic reaction because heat is absorbed in this reaction.
• An endotheumic reaction is usually indicated by writing + Heat or + Heat energy or just”+ Energy” on the reactants side of an equation.

Question 15.
Balance the following equations.
1) Na + O₂ → Na₂O
2) H₂O₂ → H₂O + O₂
3) Mg(OH)₂ + HCl → MgCl₂ + H₂O
4) Fe + O₂ → Fe₂O₂
Answer:

1. 4 Na + O₂ → 2 Na₂O
2. 2 H₂O₂ → 2 H₂O + O₂
3. Mg(OH)₂ + 2 HCl → MgCl₂ + 2 H₂O
4. 4 Fe + 3 O₂ → 2 Fe₂O₃

Question 16.
2 Cu + O₂ → 2 CuO
What information do you get from above equation?
Answer:
The above equation tells us that,

1. Copper reacts with oxygen to form copper oxide.
2. The formula of copper oxide is CuO and that of oxygen is O₂.
3. 2 moles of copper atoms react with 1 mole of oxygen molecules (O₂) to produce 2 moles of copper oxide (CuO).

Question 17.
Write examples for oxidation reaction.
Answer:
Oxidation :
It is a reaction involving addition of oxygen or removal of hydrogen from a substance.
1) Magnesium reacts with oxygen to form magnesium oxide.
2 Mg + O₂ → 2 MgO

2) Copper reacts with oxygen to form copper oxide.
2 Cu + O₂ → 2 CuO

3) Iron reacts with oxygen to form ferric oxide.
4 Fe + 3 O₂ → 2Fe₂O₃

Question 18.
Write examples for reduction reaction.
Answer:
Reduction :
It is a reaction involving addition of hydrogen or removal of oxygen from a substance.
1) Nitrogen gas reacts with hydrogen gas to produce Ammonia.
N₂ + 3H₂ → 2NH₃

2) Oil reacts with hydrogen to form fat.
Oil + H₂ → Fat

Question 19.
Write the examples for corrosion reaction.
Answer:
1) The black coatings on silver.
4 Ag + 2H₂S + O₂ → 2 Ag₂S + 2H₂O

2) Green coating on copper.
2 Cu + O₂ → 2 CuO

Question 20.
Name the reactants and products in the following chemical equations.
Na₂SO₄ + BaCl₂ → BaSO₄ + NaCl
Answer:
Reactants are Sodium sulphate and Barium chloride. Products are Barium sulphate and Sodium chloride.

Question 21.
Balance the following chemical equation and follow the steps involved in balancing a chemical equation.
Cu₂S + O₂ → Cu₂O + SO₂
Answer:
Step – 1 : Write the unbalanced equation using correct chemical formula for all substances.
Cu₂S + O₂ → Cu₂O + SO₂

Step – 2 : Compare number of atoms of each element on both sides.

Atom	No. of atoms in LHS	No. of atoms in RHS
Cu	2	2
S	1	1
O	2	3

Balancing Cu, S, O atoms both sides
2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂
The equation is balanced.

Step – 3 : Write the coefficient of smallest ratio.
2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂

Step – 4 : Verify above equation for balancing of atoms of each element on both sides.
2Cu₂S + 3O₂ → 2Cu₂O + 2SO₂

Question 22.
Write the difference between oxidation and reduction. Give example.
Answer:

Oxidation	Reduction
1) Addition of oxygen or removal hydrogen from a compound is called oxidation.	1) Addition of hydrogen or removal of oxygen from a compound is called reduction.
2) e.g.: C + O2 → CO2	2) e.g. :N2 + 3H2 → 2NH3

Question 23.
Give two examples for chemical reactions in which precipitate is formed.
Answer:
The reactions in which a substance insoluble in water is formed are called precipitation reactions.
e.g.:
1) When lead nitrate solution reacts with potassium iodide solution it forms a yellow precipitate of lead iodide.
Pb(NO₃)_2(aq) + 2KI_(aq) → PbI_2(s) + 2KNO_3(aq)

2) When sodium sulphate solution reacts with barium chloride solution it forms a white precipitate of barium sulphate.
Na₂SO4_(aq) + BaCl_2(aq) → BaSO_4(s) + 2NaCl_(aq)

Question 24.
What are exothermic and endothermic reactions?
Answer:
Exothermic reaction :
A chemical reaction in which heat is released is called exothermic reaction.
Ex :
C + O₂ → CO₂ + Heat,
CaO + H₂O → Ca(OH)₂ + Heat

Endothermic reaction :
A chemical reaction in which heat is absorbed is called endothermic reaction.
Ex :
2NaHCO₃ + Heat → Na₂CO₃ + H₂O + CO₂

Question 25.
What is an alloy? Give one example.
Answer:
A metallic substance made by mixing and fusing two or more metals or a metal and a non-metal, to obtain desirable qualities such as hardness, lightness and strength is called alloy.
Ex : Brass, bronze, steel.

Question 26.
What is photochemical reaction? Give example.
Answer:
The decomposition reaction occurs in the presence of sunlight is called photochemical.. reaction.
Ex : 2AgBr_(s) → 2Ag_(s) + Br_2(g)

Question 27.
Why is power supply to our home from the electrical pole interrupted?
Answer:

• Sometimes during rainy season the power supply to our home from the electric pole will be interrupted due to the formation of the metal oxide layer on the electric wire.
• This metal oxide is an electrical insulator.

Question 28.
Name the reactions involved in the following reactions with reasons.

Answer:
a) It is a decomposition reaction carried out in the presence of heat. So it is thermal decomposition reaction.
b) It is a decomposition reaction carried out in the presence of light. So it is photochemical reaction.
c) It is a decomposition taking place in the presence of electricity. So it is electrolysis reaction.
d) Lead is more reactive than copper. So lead displaces copper from salt solution. So the reaction is chemical displacement reaction.

Question 29.
Ramu told Ravi that all material made of iron and its alloys are rusted when exposed to air. How do you correct him by asking suitable questions?
Answer:

1. What are the material we will generally use in our cooking utensils?
2.  What are the material used for surgical equipments?
3. What happens when stainless steel vessels are exposed to air?

Question 30.
What are the gases released when lead nitrate is heated and how do you identify those gases?
Answer:
When lead nitrate is heated it decomposes into lead oxide, nitrogen dioxide and oxygen.

Nitrogen diox-ide is identified by its reddish brown co|our. Oxygen makes the burning splinter to burn brightly when it is placed in test tube containing oxygen.

Question 31.
Write some chemical reactions occurring in our daily life.
Answer:

1. Souring of milk
2. Formation of curd from milk
3. Cooking of food
4. Digestion of food in our body
5. Fermentation of grapes
6. Rusting of iron
7. Burning of fuels
8. Burning of candle wax
9. Ripening of fruits.

Question 32.
If 40 gm of methane is burnt, then how much amount of CO₂ is released ?
Answer:

When 16 g of methane is burnt it releases 44 g of CO₂. The amount of CO₂ released when 40 g methane burnt 44
= \(\frac{44}{16}\) × 40=110g

Question 33.
Calculate the amount of calcium oxide formed when 2 kg of calcium carbonate is decomposed. (The atomic masses of Ca = 40 U, C = 12 U, O = 16 U).
Answer:
The balanced equation is
CaCO_3(s) → CaO_(s) + CO_2(g)
(40 + 12 + 3 x 16) U → (40 + 16) U + (12 + 2 x 16) U
100 U → 56 U + 44 U
100 g → 56g + 44g
100 g calcium carbonate on decomposition produces 56 g of calcium oxide.
Amount of calcium oxide formed due to decomposition of 2 kg of calcium carbonate

Question 34.
A solution of common salt when added to silver nitrate solution yields a precipitate of silver chloride (0.28 g). Find the mass of sodium chloride in the solution and also the mass of sodium nitrate formed.
Answer:

Question 35.
0.29 g of hydrocarbon when burnt completely in oxygen produces 448 ml of carbon dioxide at STP. From the information, calculate the
i) mass of carbon dioxide formed
ii) mass of element carbon in carbon dioxide
iii) mass of hydrogen in hydrocarbon.
Answer:
i) Gram molecular weight of carbon dioxide = 12 + 2 × 16g = 44 g.
22.4 litres of CO₂ at STP weighs 44 g.

The weight of 448 ml of CO₂ at STP = \(\frac{44}{22400}\) × 448 = 0.88 g

ii) 44g of CO₂ contains 12 g of carbon.
The amount of carbon present in 0.88 g of CO₂ = \(\frac{12}{44}\) × 0.88 = 0.24 g

iii) Weight of hydrogen = Weight of hydrocarbon – Weight of carbon
= 0.29 – 0.24 = 0.05 g

Question 36.
Calculate the weights of carbon dioxide and water that will be obtained by completely burning 0.25 g of an organic compound having molecular formula C₄H₄O₄.
Answer:

Question 37.
What weight of sulphuric acid will be required to completely dissolve 3g of magnesium carbonate? Calculate the volume of carbon dioxide evolved at STP.
Answer:

Question 38.
If 16.4 g of calcium nitrate is heated : (a) Calculate the volume of Nitrogen dioxide obtained at STP and (b) The mass of calcium oxide obtained.
Answer:

Question 39.
Give some examples for corroded and non-corroded metals and give the reasons for non-corrosion of metals.
Answer:
Examples to corroded metals :

1. Iron
2. Copper
3. Silver

Reactions:
4Fe + 3O₂ → 2Fe₂O₃
2Cu + O₂ → 2CuO
4Ag + 2H₂S + O₂ → 2Ag₂S + 2H₂O

Exmples to non-corroded metals :

1. Gold
2. Platinum
3. Brass
4. Bronze
5. Steel

Reasons:

1. Gold and platinum metals do not react with oxygen and have resistance to corrosion.
2. Brass, bronze and steel are alloys. So they have a quality of resistance to corrosion.

Question 40.
Iron is a corroded metal. Through alloying we can prevent corrosion. Justify.
Answer:

• Alloying is a very good method of improving properties of metal.
• Generally pure form of iron is very soft and stretches easily when hot.
• When iron is mixed with carbon, nickel and chromium, an alloy stainless steel is obtained.
• The stainless steel is hard and does not rust.
• So, through alloying iron we can prevent corrosion.

Question 41.
“Through alloying corrosion can be prevented.” For the justification pose some questions.
Answer:

1. What is alloying?
2. How are alloys prepared?
3. What are the qualities of alloys?
4. Which quantity prevents the corrosion in alloys?
5. Can we prevent corrosion by alloying a metal ?

9th Class Physical Science6th Lesson Chemical Reactions and Equations 4 Marks Important Questions and Answers

Question 1.
Write the balanced chemical reaction for the following and identify the type of reaction in each case.
A) Magnesium_(s) + Iodine_(g) → Magnesium iodide_(s)
B) Zinc_(s) + Hydrochloric acid_(aq) → Zinc chloride_(aq) + Hydrogen_(g)
Answer:
A) Magnesium_(s) + Iodine_(g) → Magnesium iodide_(s)
Mg + I₂ → Mgl₂. This reaction is chemical combination.

B) Zinc_(s) + Hydrochloric acid_(aq) → Zinc chloride_(aq) + Hydrogen_(g)
Zn + 2HCl → ZnCl₂ + H₂ ↑
This reaction is chemical displacement.

Question 2.
Write an activity to each of the following chemical reaction.
A) Photo chemical reaction
B) Chemical displacement reaction.
Answer:
A) Photo chemical reaction :
1) Take a pinch of Silver Bromide in a watch glass and it in the presence of sunlight.
2) Silver Bromide decomposes to silver and Bromine in sunlight.

B) Chemical displacement:

1. Take a small quantity of zinc dust in a conical flask and add some drops of dilute hydrochloric acid slowly.
2. Immediately we can observe the gas bubbles coming out from the solution.
3. This is because zinc reacts with dilute hydrochloric acid and liberates hydrogen gas.
   Zn + 2HCl → ZnCl₂ + H₂ ↑
4. In this reaction the element zinc has displaced hydrogen from hydrochloric acid.

Question 3.
Why should we balance a chemical equation ? Take any one chemical equation and explain the procedure of balancing it.
Answer:
Chemical reactions obey law of conservation of mass. So the total number of atoms of each elements in the reactants must be equal to the total number of atoms of each element in the

products. So we should have to balance chemical equation.
Eg : H₂ + O₂ → H₂O

Step -1 : Unbalanced equation = H₂ + O₂ → H₂O
Step – 2 : Compare no.of atoms of each element on both sides.

Atom	No. of atoms in L.H.S	No. of atoms in R.H.S
H	2 (in H2)	2 (in H2O)
0	2 (in O2)	1 (in H2O)

No.of 0 atoms balancing – H₂ + O₂ → 2H₂O
No.of H atoms balancing – 2H₂ + O₂ → 2H₂O

Step – 3 : The above equation is balanced and write the coefficients in the smallest ratio. 2H₂ + O₂ → 2H₂O

Step – 4 : Verify above equation for balancing of atoms each element on both sides. Hence the equation is balanced.
∴ 2H₂ + O₂ → 2H₂O

Question 4.
Balance the following chemical equations.
i) Zn_(s) + Ag NO_3(aq) → Zn (NO₃)_2(aq) + Ag_(s)
ii) Fe₂O_3(s) + C_(s) → Fe_(s) + CO_2(g)
iii) Ag_(s) + H₂S_(g) → Ag₂S_(s) + H₂O_(l)
iv) Cu_(s) + O_2(g) → CuO_(g)
Answer:
i) Zn_(s) + Ag NO_3(aq) → Zn (NO₃)_2(aq) + Ag_(s)
Balanced equation : Zn_(s) + 2 AgNO_3(aq) → Zn (NO₃)_2(aq) + 2Ag_(s)

ii) Fe₂O_3(s) + C_(s) → Fe_(s) + CO_2(g)
Balanced equation : 2Fe₂O_3(s) + 3C_(s) → 4Fe_(s) + 3CO_2(g)

iii) Ag_(s) + H₂S_(g) → Ag₂S_(s) + H₂O_(l)
Balanced equation :
We cannot balance the equation because atom ‘O’ does not exist in the reactants.

iv) Cu_(s) + O_2(g) → CuO_(s)
Balanced equation :
2Cu_(s) + O_2(g) → 2CuO_(s)

Question 5.
Write the equation for the reaction of zinc with hydrochloric acid and balance the equation. Find out the number of molecules of hydrogen gas produced in this reaction, when 1 mole of HCl completely reacts at S.T.P.
[Gram molar volume is 22.4 liters at S.T.P., Avogadro’s number is 6.023 × 10²³]
Answer:
Zn + 2HCl → ZnCl₂ + H₂

• In the reaction 2 moles of HC/ produce 1 mole of H₂.
• If 1 mole of HCl participate in reaction, Vi mole of hydrogen will be produced.
• 1 mole of H₂ gas contains 6.023 × 10²³ molecules at STP.
  Number of molecules in ½ mole of H₂ gas = 6.023 × 10²³ × ½ = 3.011 × 10²³

Question 6.
Write the examples for chemical combination.
Answer:
1) Magnesium burns in oxygen to form magnesium oxide.
2 Mg + O₂ → 2 MgO

2) When coal is burnt in oxygen, carbon dioxide is produced.
C + O₂ → CO₂ + Q (cheat energy)

3) Slaked lime is prepared by adding water to quick lime.
CaO + H₂O → Ca(OH)₂ + Q (heat energy)

4) When hydrogen reacts with oxygen, it gives water.
H₂ + O₂ → 2 H₂O

5) Hydrochloric acid is obtained by adding hydrogen to chlorine.
H₂ + Cl₂ → 2 HCl

6) Magnesium reacts with iodine to magnesium iodide.
Mg + l₂ → Mgl₂

7) Sodium reacts with chlorine to form sodium chloride.
2 Na +Cl₂ → 2 NaCl

8) Iron reacts with oxygen to form haematite.
Fe + 3O₂ → 2 Fe₂O₃

Question 7.
Write examples for chemical decomposition reaction.
Answer:
1) Calcium carbonate on heating decomposes to calcium oxide and carbon dioxide.

2) On electrolysis, water decomposes to water and hydrogen.
2 H₂O → 2 H₂ + O₂

3) Silver bromide decomposes to silver and bromine in sunlight.
2 AgBr → 2 Ag + Br₂

4) Silver chloride decomposes to silver and chlorine.
2 AgCl → 2 Ag + Cl₂

5) Glucose decomposes to ethanol and carbon dioxide.
C₆H₁₂O₆ → 2 C₂H₅OH + 2 CO₂

6) Sodium bicarbonate decomposes to sodium carbonate, water and carbon dioxide.
2 NaHCO₃ + Heat → Na₂CO₃ + H₂O + CO₂

7) On heating lead nitrate decomposes to lead oxide, oxygen and nitrogen dioxide.

Question 8.
Write the examples for chemical displacement reaction.
Answer:
1) Zinc pieces react with dilute hydrochloric acid and liberate hydrogen gas
Zn + 2 HCl → ZnCl₂ + H₂

2) Iron reacts copper sulphate to form iron sulphate and copper.
Fe + CuSO₄ → FeSO₄ + Cu

3) Zinc is mixed with silver nitrate to form zinc nitrate and silver.
Zn + 2 AgNO₃ → Zn(NO₃)₂ + 2Ag

4) Lead reacts with copper chloride to form lead chloride and copper.
Pb + CuCl₂ → PbCl₂ + Cu

5) Sodium reacts with water to form sodium hydroxide and hydrogen.
2 Na + 2H₂O → 2 NaOH + H₂

6) Aluminium reacts with copper chloride to form aluminium chloride and copper.
2 Al + 3 CuCl₂ → 2 AlCl₃ + 3 Cu

7) Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen.
Zn + H₂SO₄ → ZnSO₄ + H₂

Question 9.
Write examples for chemical double displacement reaction.
Answer:
1) Sodium sulphate solution on mixing with barium chloride solution forms a white precipitate of barium sulphate and soluble sodium chloride.
Na₂SO₄ + BaCl₂ → BaSO₄ + 2 NaCl

2) Sodium hydroxide reacts with hydrochloric acid to form sodium chloride and water.
NaOH + HCl → NaCl + H₂O

3) Sodium chloride spontaneously combines with silver nitrate in solution giving silver chloride precipitate.
NaCl + AgNO₃ → AgCl + NaNO₃

4) Mix lead nitrate solution and potassium iodide solution to form a yellow precipitate of lead iodide and potassium nitrate.
Pb(NO₃)₂ + 2Kl → PbI₂ + 2KNO₃

5) Calcium hydroxide reacts with nitric acid to form water and calcium nitrate.
Ca(OH)₂ + 2 HNO₃ → 2H₂O + Ca(NO₃)₂

6) Magnesium chloride reacts with potassium hydroxide to form magnesium hydroxide and potassium chloride.
MgCl₂ + 2 KOH → Mg(OH)₂ + 2 KCl

Question 10.
Balance the following equations.
1) Al(OH)₃ → Al₂O₃ + H₂O
2) NH₃ + CuO → Cu + N₂ + H₂O
3) Al₂(SO₄)₃ + NaOH → Al(OH)₃ + Na₂SO₄
4) HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + H₂O
5) NaOH + H₂SO₄ → Na₂SO₄ + H₂O
6) BaCl₂ + H₂SO₄ → BaSO₄ + HCl
Answer:

1. 2 Al(OH)₃ → Al₂O₃ + 3 H₂O
2. 2 NH₃ + 3 CuO → 3 Cu + N₂ + 3 H₂O
3. Al₂(SO)₃ + 6 NaOH → 2 Al(OH)₃ + 3 Na₂SO₄
4. 2 HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + 2 H₂O
5. 2 NaOH + H₂SO₄ → Na₂SO₄ + 2 H₂O
6. BaCl₂ + H₂SO₄ → BaSO₄ + 2 HCl

Question 11.
How many types of chemical reactions are there? Explain with examples.
Answer:
There are four types of chemical reactions. They are :
i) Chemical combination :
A chemical reaction in which two or more substances combine together to form a new substance is called chemical combination.
e.g.: 2H₂ + O₂ → 2H₂O
CaO + H₂O → Ca(OH)₂

ii) Chemical decomposition :
The reaction in which a compound breaks up into two or more simpler substances are known as decomposition reaction. These reactions are generally carried out by means of heat, light, electricity or catalysts.
e.g.: CaCO₃ → CaO + CO₂
2Pb(NO₃)₂ → 2 PbO + 4NO₂ + O₂

iii) Chemical displacement:
The chemical reaction in which one element takes the place of another element in a compound is called displacement reaction.
In these reactions, an atom or group of atoms in a molecule is replaced by another atom or a group of atoms.
e.g.: Zn + 2HCl → ZnCl₂ + H₂ ↑
Zn + CuSO₄ → ZnSO₄ + Cu

iv) Chemical double displacement: The reaction in which two compounds react to form two other compounds by mutual exchange of their ions is called double displacement reaction.
e.g.: NaOH_(aq) + HCl_(aq) → NaCl_(aq) + H₂O_(l)
NaNO_3(aq) + AgCl_(aq) → AgNO_3(s) + NaCl_(aq)

Question 12.
Balance the following chemical equations.
a) Na₂SO₄ + BaCl₂ → BaSO₄ + NaCl
b) Al₄C₃ + H₂O → CH₄ + Al(OH)₃
c) Pb(NO₃)₂ → PbO + NO₂ + O₂
d) Fe₂O₃ + Al → Al₂O₃ + Fe
Answer:
a) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
b) Al₄C₃ + 12H₂O → 3CH₄ + 4Al(OH)₃
c) 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
d) Fe₂O₃ + 2Al → Al₂O₃ + 2Fe

Question 13.
How can we make a chemical equation information?
Chemical equations can be made more informative by expressing following characteristics of the reactants and products.
1. Expressing the physical state :
The different states, i.e. gaseous, liquid and solid states are represented by the notations (g), (l) and (s) respectively. If the substance is present as a solution in water the word aqueous is written.

2. Expressing the heat changes :
Q is heat energy which is shown with plus ’+’ sign on product side for exothermic reactions and minus sign on product side for endothermic reactions.
e.g.: a) C_(s) + O_2(g) → CO_2(g) + Q (exothermic reaction)
N_2(g) + O_2(g) → 2NO_(g) ” Q (endothermic reaction)

3. Expressing the gas evolved :
If a gas evolved in a reaction, it is denoted by an upward arrow ↑ or (g).
Zn_(s) + H₂SO_4(aq) → ZnSO_4(aq) + H_2(g)↑

4. Expressing precipitate formed: If a precipitate is formed in the reaction, it is denoted by downward arrow ↓.
AgNO_3(aq) + NaCl_(aq) → AgCl_(s) ↓ + NaNO_3(aq)

Question 14.
Give daily life examples of oxidation.
Answer:
Daily life examples :

1. Combustion of fuels.
2. Corrosion of metals.
3. Change of colour of fruits like apples, bananas, when they are cut.
4. Burning of crackers.
5. Rancidity of food material.
6. During rainy season the power supply to our home from the electric pole will be interrupted due to formation of metal oxide layer on the electric wire.
7. Rising of dough with yeast depends on oxidation of sugars to carbon dioxide and water.
8. Bleaching of coloured objects using moist chlorine.
9. Respiration.

Question 15.
What is the information giyen by balanced chemical equation?
Answer:

• A chemical equation gives information about the reactants and products through their symbols and formulae.
• It gives the ratio of molecules of reactants and products.
• As molecular masses are expressed in unified masses, the relative masses of reactants and products are known from the equation.
• If the masses are expressed in grams, then the equation also gives the molar ratios of reactants and products.
• If gases are involved, we can equate the masses to their volumes.
• Using molar mass and Avagadro’s number we can calculate the number of molecules and atoms of different substances from the equation.

Question 16.
Write the balanced equation and identify the type of reaction.
1) Magnesium Hydroxide_(aq) + Nitric Acid_(aq) → Magnesium Nitrate_(aq) + Water_(l)
2) Magnesium_(s) + Carbon Monoxide_(g) → Magnesium Oxide_(s) + Carbon_(g)
3) Barium Chloride_(aq) + Sodium Sulphate_(aq) → Barium Sulphate_(s) + Sodium Chloride_(aq)
4) Sodium Nitrate_(s) → Sodium Nitrite_(s) + Oxygen_(g)
Answer:
1) Mg(OH)_2(aq) + 2 HNO_3(aq) → Mg(NO₃)_2(aq) + 2 H₂O_(l)
It is both double displacement and neutralisation reaction.

2) Mg_(s) + CO_(g) → MgO_(s) + C_(s)
It is a redox reaction in which magnesium is oxidised and carbon monoxide is reduced.

3) BaCl_2(aq) + Na₂SO_4(aq) → BaSO_4(s) ↓ + 2 NaCl_(aq)
It is both precipitation and double displacement reaction.

4) 2 NaNO_3(s) → 2 NaNO_2(s) + O_2(g)
It is both endothermic and decomposition reaction.

Question 17.
We write symbol of water as H₂O. State why we should not write it as HO₂.
Answer:
1) The hydrogen atom has only T electron in its outermost shell, so it needs 1 more electron to achieve the stability. ‘2’ electrons are required to get inert gas electronic configuration.

2) The oxygen atom has ‘6’ electrons in its outermost shell and it needs ‘2’ more electrons to compare the stability. ‘8’ electron arrangement of inert gas is neon.

In the water molecule, central oxygen atom has two pairs of unshared electrons which have not been utilised in the formation of bonds.

So, we write symbol of water as H20 and we should not write it as HO₂.

Question 18.
Latha took some quantity of powder of a substance in a test tube. Heated it with spirit lamp. A gas was liberated. She sent the gas into another test tube. The colour of solution in the second test tube turned into milk white.
Answer the following questions :
a) Which substance was heated?
b) Which gas was liberated?
c) What was the solution taken in second test tube?
d) Which type of chemical reactions involved the experiment?
Answer:
a) The substance is calcium carbonate.
b) The gas liberated is carbon dioxide.
c) The solution taken in the second test tube was solution of slaked lime.
d) Two types of reactions took place in this experiment, i.e. decomposition and double displacement.
CaCO_3(s) → CaO_(s) . CO₂ ↑
Ca(OH)_2(aq) + CO_2(g) → CaCO_3(s) + H₂O

Question 19.
A light yellow colour substance (some quantity) on a watch glass is put in the sunlight. It changes into grey colour substance.
a) What is the light yellow colour substance?
b) What is the grey colour substance?
c) Which type of chemical reaction it is?
d) Write the chemical equation for the reaction.
Answer:
a) The light yellow colour substance is silver bromide.
b) The grey colour substance is silver.
c) The type of chemical reaction is photochemical reaction.

Question 20.
Heat is liberated in the reactions where water is added to calcium oxide and hydrochloric acid added to zinc pieces.
Rarnu says that they are same type of chemical reactions. Eswar’s opinion is that the reactions are not similar. What is the basis of Eswar’s opinion ? Write equations for the above reaction.
Answer:
Eswar’s thinking is correct. Although both are exothermic reactions, the type of chemical reactions is different.
Case (i) : When water is added to calcium oxide it forms calcium hydroxide. It is an example for combination reaction.
CaO_(s) + H₂O → Ca(OH)_2(aq)

Case (ii) : When hydrochloric acid is added to zinc pieces it would liberate hydrogen gas which is an example for displacement reaction.
Zn_(s) + HCl_(aq) → ZnCl_2(aq) + H_2(g) ↑

Question 21.
We see many combustion and oxidation reactions in our daily life. Among them every combustion reaction is an oxidation reaction. But not all the oxidation reactions are combustion reactions. Do you agree or disagree with the statement? Explain with proper reasons.
Answer:
1) Yes, I agree with the statement because combustion reaction is nothing but burning of a substance in the presence of oxygen so it is an oxidation reaction. So every combustion reaction is an oxidation reaction.

2) Whereas some reactions which do not require burning still they are oxidation reactions.
Eg :

1. Corrosion of metals.
2. Change of colour of fruits like apples, bananas when they are cut.
3. Rancidity of food materials.
4. Respiration.
5. Bleaching of coloured objects using moist chlorine.
   So all oxidation reactions are not combustion reactions.

Question 22.
Explain the following :
1) What happens when iron filings are added to zinc sulphate solution?
2) What happens when solid silver nitrate is added to solid sodium chloride?
Answer:
1) No reaction takes place because zinc is more reactive than iron. So iron cannot displace zinc from its salt solution.

2) No reaction takes place because in solid state silver nitrate as well as sodium chloride is unable to dissociate into constituent ions. So exchange of ions is not possible.

Question 23.
Why is steel not used for surgical equipment and what is the material used for surgical equipment? Why is that material used for surgical equipment?
Answer:
1) Steel undergoes rusting when It exposed to air. So it is not useful for preparation of surgical equipment. If we use it in surgical equipment it may cause septic of wound.

2) The material used for surgical equipment is stainless steel which is an alloy of iron, carbon, nickel and chromium. Chromium does not easily react with oxygen. So, addition of chromium makes the stainless steel free from rusting. Therefore it is used in surgical equipment.

Question 24.
Give reasons for the following.
1) Why do we add salt to water during electrolysis of water?
2) Why does hydrogen gas put off the burning splinter and it burns with blue flame?
3) Why does carbon dioxide turn lime water milky?
Answer:
1) Pure water is a bad conductor of electricity. By adding a small amount of salt the solution becomes conductor of electricity.

2) Hydrogen does not support combustion. So it puts off the burning splinter and also it is combustible. So burns with blue flame.

3) When we pass carbon dioxide through lime water it turns into milky because lime water (calcium hydroxide) reacts with carbon dioxide and forms a white milky substance, i.e. calcium carbonate.

Question 25.
A student was given the following substances and was asked to show types of chemical reactions through experiment. Write how he would have done that. Copper sulphate solution, barium chloride solution, ferrous sulphate crystals, iron nails, calcium oxide, water.
Answer:
Given chemicals are CuSO₄ solution, BaSO₄ solution, iron nails (Fe), Ferrous sulphate (FeSO₄), Calcium oxide (CaO) and water (H₂O).

i) Chemical combination :
Chemicals chosen : CaO, H₂O
CaO + H₂O → Ca(OH)₂

When we add water to calcium oxide it produces Calcium hydroxide. This is an example for chemical combination.

ii) Chemical decomposition:
Chemicals chosen : Ferrous sulphate

When we heat FeSO₄ it dissociates into Ferric oxide, Sulphur dioxide and Sulphur trioxide respectively.

iii) Chemical displacement :
Chemicals chosen : Iron nail – CuSO₄
Fe + CuSO₄ → FeSO₄ + Cu ↓

When iron nail is placed in CuSO₄ solution, the solution turns into light green due to formation of FeSO₄ and reddish brown deposit of Copper.

iv) Double displacement:
Chemicals chosen : CuSO₄ solution and BaCl2 solution.
CuSO_4(aq) + BaCl_2(aq) → BaSO_4(s) ↓ + CuCl_2(s)

When CuSO₄ is mixed with BaCl₂ solution it forms white precipitate of BaSO₄ and aqueous solution of Copper (II) Chloride.

This is an example for double displacement reaction.

Question 26.
Take two beakers and prepare lead nitrate aqueous solution and potassium iodide aqueous solutions. What are the colours of the solutions? Now mix them in another beaker. What happens? What type of chemical reaction it is? What are products?
Answer:
The colours of the solutions are white or colourless. When lead nitrate solution is mixed with potassium iodide solution we will get yellow precipitate of lead iodide. This is double displacement reaction. The products are lead iodide and potassium nitrate.
Pb(NO₃)_2(aq) + 2Kl_(aq) → Pbl_2(s) + 2KNO_3(aq)

Question 27.
Observe the following equation which shows the action of heat on Calcium Nitrate
2 Ca(NO₃)₂ → 2 CaO + 4 NO₂ + O₂
a) How many moles of NO₂ are formed when a mole of 2 Ca(NO₃)₂ is decomposed?
b) What is the volume of NO₂ produced when 164 gm of Ca(NO₃)₂ is heated at constant temperature and pressure?
c) Calculate the mass of Calcium Oxide formed when 82 gm of Ca(NO₃)₂ is heated.
d) What is the quantity of Ca(NO₃)₂ required to produce 5 moles of gaseous products?
Answer:
Given balanced equation is
a) From the balanced equation 2 moles of Ca(NO₃)₂ releases 4 moles of NO₂.
b) Molecular weight of Ca(NO₃)₂ and CaO respectively are 164 and 56.
From the equation at STP 2 × 164 g. of Ca(NO₃)₂ releases 4 × 22.4 litres of NO₂.
At similar conditions 164 g. of Ca(NO₃)₂ releasing NO₂ in litres is
= \(\frac{164}{2 \times 164}\) × 22.4 × 4 = 2 × 22.4 = 44.8 liters.

c) From the balanced equation 164 g. of Ca(NO₃)₂ decomposes and forms 112 g. of CaO. Similarly 82 g. of Ca(NO₃)₂ decomposes and forms
\(\frac{82}{164}\) × 112 = 56 g. of CaO.

d) From the above balanced equation 2 moles of Ca(NO₃)₂ releases 5 moles of gaseous products.
∴ The mass of Ca(NO₃)₂ required is 2 × 164 = 328 g.

Question 28.
Zn + HCl → ZnCl₂ + H₂
Calculate amount of zinc required to release 500g of hydrogen. (Zn = 65 U, H = 1 U, Cl = 35.5 U are the atomic masses).
Answer:
The balanced chemical equation is
Zn + 2 HCl → ZnCl₂ + H₂
65 U + (2 × 36.5) U → (65 + 2 × 35.5) U + 2 U
65 g + 73 g → 136 g + 2g
As per the balanced equation
65 g Zinc is reacting with hydrochloric acid to produce 2g of Hydrogen.

Question 29.
Calculate the volume, mass and number of molecules of carbon dioxide when 104 g of acetylene (C₂H₂) burnt in air. (Atomic masses of C = 12 U, H = 1 U, O = 16 U).
Answer:
The balanced chemical equation is
2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O
2 × (2 × 12U + 2 × lU) + 5 × (2 × 16U) → 4 × (12U + 2 × 16U) + 2(2 × 1U + 16U)
52 g + 160g → 176 g + 36 g
52 g of acetylene when burnt in air produces 176 g carbon dioxide.
The amount of carbon dioxide produced when 104 g acetylene burnt

At S.T.P. 1 gram molar mass of any gas occupies 22.4 litres.
So 44g carbon dioxide occupies 22.4 litres volume.
The volume occupied by 352 g carbon dioxide = \(\frac{352}{44}\) × 22.4 = 8 × 22.4 = 179.2 litres.
44 g of carbon dioxide i.e., 1 mole of CO₂ contains 6.02 × 10²³ molecules. So the number of molecules present in 352 g of carbon dioxide
352
= \(\frac{352}{44}\) × 6.02 × 10²³ = 8 × 6.02 × 10²³
= 4.816 × 10²⁴ molecules.

SCERT AP 7th Class English Government Textbook Answers Unit 1 My Painted House, Friendly Chicken and Me Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 1 Questions and Answers My Painted House, Friendly Chicken and Me

7th Class English Unit 1 My Painted House, Friendly Chicken and Me Textbook Questions and Answers

Observe the picture. Discuss and answer the questions.

Question 1.
Where are the children?
Answer:
The children are near their houses.

Question 2.
Is it a village or a town? Why?
Answer:
It is a village. It is not a town. The houses, the location and the animals reflect a village scene.

Question 3.
What are the boys looking at?
Answer:
The boys are looking at the animals and eggs.

Question 4.
Are the children friendly with the animals? Discuss.
Answer:
Yes, the children are friendly with the animals. They are helping the animals in different ways.

Question 5.
What are the children doing?
Answer:
The children are spending their time with the animals and birds.

Questions Given in the Lesson

Possible answers to the questions given in the middle of the lesson and at the end:

Question 1.
What’s in a name?
Find out more about your name. Does it have a special meaning? Share it with your classmates.
Answer:
My name is Nageswara Rao. It has a special meaning. Two Hindu deities are there in my name. ‘Naga’ means ‘Naga Devatha’ and ‘Eswara’ means ‘Lord Parameshwara’.

Question 2.
Can you think of some pictures that can be drawn with a feather?
Answer:
We can draw pictures of birds, moon, stars, sun, sky, all the things related to nature, different designs and a number of other things with a feather.

Question 3.
How are colours used to decorate the houses in villages during festivals?
Answer:
The villagers decora their houses with different colours during festivals. Most of them use dark colours which bring life to the painting. They paint the pictures of deities, some designs, circles, symbols, etc. on the walls of their houses and celebrate the festivals happily.

Question 4.
Where do you see such pictures?
Answer:
I find those pictures in the exhibitions and in the shops located in pilgrimage places.

Question 5.
List out the activities done by Ndebele women.
Answer:
i) They paint their houses with colourful and intricate patterns.
ii) They make good things with beads.
iii) They perform their household chores with love and affection.
iv) They respect their ancestors and follow their tradition strictly.

Question 6.
How do you dress up on your birthday?
Answer:
I wear new dress brought by my father on the occasion of my birthday.

Question 7.
What do you like to wear on special occasions?
Answer:
I would like to wear specially designed clothes of different colours on special occasions.

Question 8.
Describe your village and say about the people living there in your own words.
Answer:
Our village is Machayapalem of Bellamkonda Madal, Guntur district. It is a picturesque village with narrow streets. Greenery is found everywhere. We have all kinds of animals as pets such as cats, dogs, cows, buffaloes, oxen, goats, sheep, hens, cocks, etc. in our village. Most of us live in thatched houses. Our villagers are friendly in nature. Most of them are farmers. Though we lead an ordinary life, we are always happy. We come together and celebrate the festivals. I love to live in my village.

Question 9.
Describe your best friend. What characteristics make a good friend?
Answer:
Amith is my best friend. He is honest and a true friend of mine. The characteristics such as reliability, honesty, kindness, individuality, helping nature, patience, generosity, trust, etc. make a person a good friend.

Reading Comprehension

A. Answer the following questions.

Question 1.
Who is Thandi? Who is her best friend?
Answer:
Thandi is a girl who belongs to the tribe of Ndebele from Zimbabwe and north-eastern South Africa. Thandi’s best friend is her chicken.

Question 2.
How does Thandi snatch a feather from her chicken?
Answer:
Thandi snatches a feather very quickly when the chicken is distracted and does not notice.

Question 3.
What are the two hopes of Thandi?
Answer:
The two hopes are : (1) her name which means hope and (2) At the end of the story she can say ‘Good-bye friend’, not ‘Good-bye stranger-friend’.

Question 4.
Why do you think Ndebele people do not call anything beautiful?
Answer:
Because they live in a different world. They live away from common people.

Question 5.
According to Thandi, what are some of the points to be kept in mind while painting?
Answer:
The points to be kept in mind while painting are: (1) You have to have strong eyes to paint well. (2) Your hand must not shake like leaf on a tree (3) You must fill a chicken’s feather with paint and draw a line as straight as a spear. (4) You must have the pattern inside your head, even before you dip the feather into the paint.

Question 6.
Describe the clothing of Ndebele women.
Answer:
The clothing of Ndebele women is made of beads. They shine like stars while dancing.

Question 7.
Why couldn’t Thandi’s brother be friends with chicken?
Answer:
Thandi’s brother could not be friends with a chicken because he was not able to understand animals. He shouts at chickens and they run away from him.

Question 8.
What did Thandi say about her best friend, chicken?
Answer:
Thandi says that her best friend is her chicken. The chicken listens to her stories. Her feathers are used as brushes to paint. She always spends her time with Thandi. Thandi takes her in her arms and tells her many things.

B. Say whether the following statements are True/ False:

1. Thandi’s chicken listens to her stories and has other uses.
2. Ndebele people call everything beautiful.
3. All Ndebele women paint their houses.
4. Thandi’s father built them small houses, and her mother painted them.
5. Thandi’s brother is not so mischievous.
Answer:

1. True
2. False
3. True
4. True
5. False

C. You have read the story, ‘Painted House, Friendly Chicken and Me’.

Read the interesting aspects of village life shared by Thandi mentioned in the help box.

Help Box

• Thandi’s best friend
• String and sew
• Penny whistles and bicycles
• Hand must not shake like a leaf on a tree
• Amaphotho and ghabi
• Pretend to go inside small houses built by father
• You must have the pattern inside your head.
• One can tell all their secrets

Place the sentences under the right heading. One is done for you.

Answer:

Vocabulary

A. VISUALISE – Text to Mind

Read the following sentences taken from the story, locate the phrases that are highlighted /expressions / part.

You must have the pattern inside your head, even before you dip the feather into the paint. Here the highlighted part, ‘have the pattern inside your head’ means one should visualise or have clear picture before any work.

To Visualise means to form a picture of someone or something in your mind, in order to imagine or remember him, her, or it.

Activity : Visualise the text given and draw the picture of it. One is done for you.

Note : Students are advised to do this activity on their own.

Grammar

A. Read the following sentences from the story.

1. I don’t know why, but Ndebele people do not call anything beautiful.
2. ………… no one’s house is as good as my mother’s.
3. ………. he tries to get into everybody’s business.

The highlighted words use apostrophe (‘). Now guess the use of apostrophe.

Apostrophe ( ‘ ) can be confusing or tricky. However, they aren’t difficult to learn. Sometimes they form possessives and sometimes they form contractions. Here are some tips to remember.

Apostrophe for possessions:
1. For most singular nouns, add apostrophe + s :
The cat’s tail, the student’s book, the manager’s room

2. For most plural nouns, add only an apostrophe :
The cats’ tails (multiple cats), the students’ books (multiple students); the managers’ rooms (multiple managers)

Apostrophe for contractions:
A contraction is a shortened form of a word (or group of words) that omits certain letters or sounds. In a contraction, an apostrophe represents missing letters.
He would = He’d
They are = They’re
I have = I’ve
You cannot = You can’t

Exercise

A) Write the contraction for each pair of words. Example: should not – shouldn’t
1. are not _____
2. he is _____
3. I am _____
4. she will _____
Answer:
1) aren’t
2) he’s
3) I’m
4) she’ll

B) Complete each sentence. Write the possessive forms of the noun given in the brackets.
Eg : The baby’s doll is a new brand one. (baby)
1. This is _____ textbook. (Angel)
2. The _____ blanket is blue, (boy)
Answer:
1) Angel’s
2) boy’s

B. Present Perfect Tense :

Let’s consider the following sentences from the text which denote just completed actions.
1. She has started to teach me to paint good, very good designs.
2. I have enjoyed telling you about my village.

These actions are said to be in present perfect tense (have/has + past participle).

Here are some more examples of the present perfect tense (underlined):
1. Bobby has eaten the breakfast.
2. They have called the police.
3. Has she painted the wall?

The Present Perfect Tense is used for unfinished actions with stative verbs and finished actions with focus on present situation.

Positive	Positive Short Form (Contracted Form)
I have played.	I’ve played.
You have worked.	You’ve worked.
He has written.	He’s written.
She the has walked.	She’s walked.
It has rained.	It’s rained.
We ave travelled.	We’ve travelled.
They have studied.	They’ve studied.

Negative	Negative Short Form (Contracted Form)
I have hot eaten.	I haven’t eaten.
You have not been to America.	You haven’t been to America.
He has not seen.	He hasn’t seen.
She has not played.	She hasn’t played.
It has not gone.	It hasn’t gone.
We have not danced.	We haven’t danced.

Note : Contracted forms are used in spoken form not in written form.

Exercise

Fill in the blanks with the Present Perfect form of the verb. One is done for you.
Eg : I have worked (work) today.

1. I _____ (not/work) today.
2. We _____ (buy) a new lamp.
3. We _____ (not / plan) our holiday yet.
4. Where _____ (be / you) ?
5. He _____ (write) five letters.
6. She _____ (not / see) him for a long time.
7. _____ (be / you) at school ?
8. The school _____ (not / start) yet.
Answer:

1. have not worked
2. have bought
3. have not planned
4. have you been?
5. has written
6. has not seen
7. Have you been
8. has not started

Writing

A. Read the passage from the narrative/ story. Write a dialogue.

Hello Stranger-friend,

I am Thandi, an Ndebele girl in South Africa. I am eight years old, and my best friend is a chicken. You may laugh at that, but when I tell my friend secrets, she can talk all she wants… but no one can understand her… except another chicken, of course. My chicken not only listens to my stories; she has other uses. If you play with her and take her mind off what’s going on, you can quickly – very quickly – snatch a feather or two when she is distracted. She doesn’t notice, and the feathers will come in handy later, of course.

Complete the conversation.

Thandi : Hello! Stranger-friend!

Stranger-friend : Hello! What is your name?

Thandi : I am Thandi.

Stranger-friend : Where are you from?

Thandi : I am …………………..

Stranger-friend : …………………………. ?

Thandi : I am eight years old.

Stranger-friend : …………………….. best friend?

Thandi : ………………..

Thandi : Hello Stranger-friend !

Stranger-friend : ……………………. tell …………. ?

Thandi : Secrets.

Stranger-Mend : Can …………. understand your words?

Thandi : Yes, of course.

Stranger-Mend : What else do you do with your chicken?

Thandi : ……………………………………..

Stranger-Mend : How do you snatch her feathers?

Thandi : …………………………..
Answer:
Thandi : Hello! Stranger-friend!

Stranger-Mend : Hello! What is your name?

Thandi : I am Thandi.

Stranger-Mend : Where are you from?

Thandi : I am an Ndebele girl in South Africa.

Stranger-Mend : How old are you?

Thandi : I am eight years old.

Stranger-Mend : Who is your best friend?

Thandi : My best friend is my chicken.

Thandi : Hello Stranger-friend!

Stranger-Mend : What would you tell your chicken (best friend)?

Thandi : Secrets.

Stranger-Mend : Can the chicken understand your words?

Thandi : Yes, of course.

Stranger-Mend : What else do you do with your chicken?

Thandi : I will use her feathers to paint.

Stranger-Mend : How do you snatch her feathers?

Thandi : I snatch her feathers when she does not notice.

B. Letter Writing : (Informal Letter)
Read the letter written to a friend describing the beauty of her1 village and the people living in it.

Gandhipuram. Feb 01, 2021. Dear Gayatri,I hope this letter finds you in good health.My village is near Anantapuram. It is about 100 kilometres away from the district headquarters. We have fresh air, water, and a clean environment in my village. My village is beautiful with many green fields, cattle and mango trees. We are the leading producers of mango, coconut and also tamarind. We get pure honey and ghee as well. We play in the sandy beach every evening. My friends and 1 play many Indian games that are forgotten those days like marbles, Kho- Kho, Kabaddi, etc.The villagers are helpful and cooperative to one another. We like to celebrate different occasions. We are peace-loving people. We enjoy holidays with relatives and friends. My village is a land of relations that follows the traditions and culture inherited from our ancestors. Please convey my regards to aunt and uncle. Awaiting your reply.Yours lovingly, Razia

Now, imagine you are Gayatri and write a reply letter describing the village/ locality you live in.

Answer:

Reply Letter Bhaskarnagar. Feb 7, 2021. Dear Razia, I have just got your letter this month. I knew from your letter about your town. Now it is my turn to write about me. You know that I live at Guntur. It is my hometown. It is one of the wonderful places. There are a lot of historical places. In fact, it is very beautiful, and neat and clean. There are many big shops and you can buy many things you want. The climate is pleasant. This village is famous for rich culture. On every Makara Sankranti, there will be a lot of people because there will have the bullfight. This is one of the traditional cultures. As I know this culture is given by our ancestors for 200 years. A lot of tourists come to see and enjoy. Guntur is famous for fairs. Though it is a city, It is full of greenery, farmland is full of crops and farmers are busy in their fields, trying to produce more, and more crops to be able to feed more and more people. There is no scarcity of pure milk and fresh vegetables. Guntur is famous for red chillies and pickles. People are friendly and very much concerned with each other. I send you a lot of photos of Guntur, You will know all about my town. 1 hope to hear from you soon. Yours lovingly, Gayatri.

C. Write a letter to Thandi. Describe similarities and differences between yours and her hopes, likes, dislikes and her games so that you may become good \ friends.
Answer

Guntur. July 5, 2021. Deatj Thandi,I am Mohana. I became your friend after reading your story. Now I am not your stranger friend. I am your dear friend. I want to share something with you and write this letter. I hope you are doing well.I understand that you want a life with freedom and want to be friends with animals find birds. I also have the same interest. I always spend my time with doves and hens at home. You wear your school uniform when you go to school and in free time, you wear the clothes made of using beads. 1 like the clothes of that kind. But we do not get them here in our town. Here we get dresses with embroidery designs. 1 prefer them a lot. I also go to big cities for shopping along with my mother and father. 1 like your village life. We can be very good friends hereafter.Please write to me describing your feelings.Yours lovingly, Mohana

Talking Time

A. Language Function : Introducing self, (use the help box)
Hello ! My name is ……………… .
I come from ……………… (name of the place)
I am ……………… years old. (age)
There are ……………… people in my family, (number of family)
I’m a student at ……………… (name of the school)
My favourite subject is ……………… . (favourite subject)
My hobbies are ………………, ………………., and ……………… . (hobby)
In my free time, I also enjoy ……………… . (sports/music)
I like/dislike/hate ……………… . (like/dislike)
My favourite food / drink is ……………… . (favourite food)
I study English because ……………… . (purpose)
I would like to become ……………… in future, (aim in life)

Answer:
Hello! My name is Pranavi.
I come from Kandukur. (name of the place )
I am thirteen years old. (age)
There are five people in my family, (number of family)
I’m a student at Z.P.High School, Kandukur. (name of the school)
My favourite subject is English. (favourite subject)
My hobbies are playing chess, listening to music, and gardening. (hobby)
In my free time, I also enjoy playing volleyball, (sports/music)
I like spending my time on the beaches. (like / dislike)
My favourite food is vegetable birvani. (favourite food)
My favourite drink is Sprite. (favourite drink)
I study English because I want to go abroad. (purpose)
I would like to become an English teacher in future, (aim in life)

B. Language Function: Introducing others
You have learnt how to introduce yourself. Now introduce your friend to your class using the hints given.
Hello! Friends! This is ……………… .
He/ She is from ……………… .
He/ She is in ……………… .
His / Her favourite subject is ……………… .
…………………………………………………………..
Answer:
Hello! Friends, This is Mokshitha.
She is from Lakshmi Puram. Guntur.
She is in Class Seven.
Her favourite subject is Science.
She wants to become a cardiologist in future.
She likes reading books and playing video games.
Milk is her favourite drink.
She spends her leisure time with pet animals.
She is very much interested in cricket.
She knows how to play the violin.
She is a very good friend of mine.

Listening

Listen to the following story.

UBUNTU
An anthropologist (someone who scientifically studies humans and their customs, beliefs, and relationships) created a game for the African tribal children. He placed a basket of sweets near a tree and made the children stand 100 metres away. Then he announced that whoever reached first would get all the sweets in the basket.

When he said, ready, steady, go!
Do you know what these children did?
They all held each other’s hands, ran together towards the tree, divided the sweets equally among themselves, ate the sweets, and enjoyed it. When the anthropologist asked them why they did so, they answered ‘Ubuntu’.
Which meant…’How can one be happy when the others are sad?’
Ubuntu in their language means – ‘I am because we are!’
Let all of us always have this attitude and spread happiness wherever we go.

Answer the following questions :
1. Who is an ‘anthropologist’?
Answer:
An anthropologist is someone who scientifically studies humans and their customs, beliefs and relationships.

2. What game did the anthropologist plan with the basket of sweets ?
Answer:
The child who reaches the sweet basket first will get all the sweets in it.

3. What instructions did the anthropologist give to the children to do?
Answer:
The anthropologist told them to stand 100 metres away. He placed the basket of sweets near a tree. He announced that whoever reches first would get all the sweets in the basket.

4. What did the children do on hearing the anthropologist’s instructions?
Answer:
They all held each other’s hands, ran together towards the tree, divided the sweets equally among them, ate the sweets and enjoyed.

5. What does the word ‘UBUNTU’ mean in the African tribal language?
Answer:
I am because we are.

Painted House, Friendly Chicken and Me Summary

The writer here adopts the voice of an eight-year-old Ndebele girl of South Africa, who addresses the reader as her “stranger-friend.” Thandi, whose name means Hope, describes some of her favorite things: the chicken to whom she confides her secrets, the intricately painted houses in her village, the beads her mother strings. Thandi’s narration is strong and direct, and provides a lively introduction to a long-neglected people and culture. It attempts to embrace the reader, however, seem somewhat strained (“You may call me friend, and 1 would like to call you friend”), and the use of many sizes and arrangements of type creates some choppiness. The accompanying photographs, on the other hand, do full justice to the brilliant colors of the beadwork, blankets and decorated houses of Thandi’s village, and to the various attitudes of the carefully adorned people in it.

Painted House, Friendly Chicken and Me About the Author

Maya Angelou born Marguerite Annie Johnson; (April 4,1928 – May 28, 2014) was an American poet, memoirist, and civil rights activist. She published seven autobiographies, three books of essays, several books of poetry, and is credited with a list of plays, movies, and television shows spanning over 50 years. She received dozens of awards and more than 50 honorary degrees. The first one I Know Why the Caged Bird Sings (1969); tells of her life up to the age of 17, and brought her international recognition and acclaim. Her famous poems are And Still I Rise’ (1978), ‘Mother, A Cradle to Hold Me’ (2006).

Meanings For Difficult Words

stranger-friend : someone whom you feel as your friend but
Thandi : the name of a girl who belongs to the tribe of Ndebele in South Africa
Ndebele (n) : a tribe from Zimbabwe and north-eastern South Africa and they speak the Bantu language, one of the official languages of South Africa.
chicken (n) : hen
laugh at (jphr.v) : speak something to make somebody seem silly
of course : naturally / certainly
take her mind off (phrase) : to stop her thinking about something
snatch (v) : quickly seize (something) in a rude or abrupt way
feather (n) : soft, light and hairy thing that covers a bird’s body
distracted (adj.) : unable to concentrate / inattentive
come in handy (idiom) : to be useful
later (adv.) : at a time in the future / afterward
hope (n) : a feeling of expectation for a particular thing to happen
pattern (n) : a particular way in which something is done, is organized, or happens
fringed (adj) : having a decorative border of hanging threads for clothing
pretend (v) : to give a false appearance of being, possessing, or performing; pose.
penny whistles (n) : flute like wind instrument
lose themselves (idiom) : give all their attention to something

put on (phr. v) : wear
dry (adj) : lacking freshness
wagon (n) : farm cart
mule (n) : an animal that has a horse and a donkey as parents
stare (v) : look fixedly or intently
city folk (n) : city people
mischievous (adj) : causing or showing a fondness for causing trouble in a playful way; naughty way.
tend (v) : care for or look after
get into (phr.v) : enter / interfere
can’t help (idiom) : can’t control
errand (n) : a short journey either to take a message or to take or collect something
squirmy (adj) : to twist about in a wriggling, snake like motion

Tom Paints the Fence

Comprehension

A. Answer the following questions :

Question 1.
What was the name of Tom’s Aunt ? Why was he living with his aunt?
Answer:
Tom’s Aunt was Polly. Tom was living with his Aunt Polly as he lost his mother.

Question 2.
How did Aunt Polly prove that she was strict?
Answer:
Aunt Polly proved that she was strict by asking Tom to whitewash the fence on a Saturday which was a holiday.

Question 3.
What work was assigned to Tom to do?
Answer:
Tom was assigned to paint the fence.

Question 4.
Describe the feelings of Tom when his aunt asked him to paint the fence.
Answer:
He felt that life was a burden. He sighed to do the work.

Question 5.
How did Tom become rich with gifts by the end of the day?
Answer:
Tom made his friends feel to paint the fence. They gave him some gifts to get the opportunity of painting work. Thus he became rich with the gifts by the end of the day.

Question 6.
What does “Spare the rod and Spoil the child” mean?
Answer:
If you do not punish a child when they do something wrong, they will not learn what is right.

B. Choose the correct answer from the options given.

1. What did Tom plan to do on a Saturday?
a) go to school
b) do homework
c) go for swimming
Answer:
c) go for swimming

2. Tom did not want the boys to see him whitewashing because they would
a) make fun of him
b) tell their teacher
c) throw mud at the fence
Answer:
a) make fun of him

3. How did Tom make Ben and others paint the fence?
a) by bribing them with money
b) by pretending painting to be fun
c) by threatening them
Answer:
b) by pretending painting to be fun

4. Tom was really in wealth at the end of the day, because……
a) many boys paid him
b) aunt Polly gave him money
c) he sold the paint
Answer:
a) many boys paid him

5. What did aunt Polly give him for painting the fence?
a) a doorknob
b) an apple
c) a new dress
Answer:
b) an apple

Fun Time

1. Teacher : Which one is closer, Sun or Africa?
Boddy : Sun
Teacher : Why?
Boddy : We can see the sun, but can’t see Africa.

2. What day do the chickens hate most?
Answer:
Friday (FRY-day)

Project

You have read the story “Painted House, Friendly Chicken and Me”.You might have understood how Thandi has enjoyed telling you about her village, her hopes, her mother, her brother, the beads, the painted house, and her good friend, the chicken.

Now, collect information regarding your family, friendship, home, village/ locality, traditions and culture, and make a picture gallery with your paintings, art and craft.
Answer:
My family is a joint family. We are ten in our family. I have a grandmother and a grandfather. I have two sisters and a younger brother. My uncle and aunt also live with us. My father is a farmer and my mother is a housewife. My two sisters are studying and my little brother is at play school. Our grandmother always tells us interesting stories. We usually have good time at home. 1 have two friends at my village. I play with my friends and two sisters. My village is surrounded by green fields. We make idols of Lord Ganesha with clay and worship Him. We draw many pictures on walls. We have fresh air and clean water. We celebrate all festivals and follow the old traditions. We wear new clothes on festivals. We spend time together joyfully.

Check Point

Tom Paints the Fence Summary

Tom Sawyer was an imaginative and mischievous boy. He was living with his Aunt Polly on the banks of the Mississippi. Aunt Polly was strict. She wanted to make Tom work on Saturday. So, she asked him to paint the fence. He unwillingly went near the fence with a brush and paint. He was very disappointed when he remembered his plans for the day, like going for swimming. He was upset with the thought that the boys would ridicule him for having work to do. Then he got a brilliant idea. He took his brush and started his work.

Then a boy named Ben Rogers came that way and told Tom that he had got to work even on a holiday. Tom pretended that he was doing that work willingly because that work would give him pleasure and he was enjoying himself in doing so. Soon, Ben begged Tom that he would help him and offered him an apple. Tom gave him the brush and Ben started painting. As Ben was painting, other boys named Billy and Johnny Miller also begged Tom to allow them too to paint. They presented him a kite and a pair of marbles in return. Thus, Tom turned the punishment into a bit of entertainment and tricked other boys to finish the work for him. The whole fence was whitewashed nicely within afternoon. When Aunt Polly saw the painted fence, she was so amazed that she gave him the best apple and allowed him to play.

Tom Paints the Fence About the Author

Mark Twain (1835-1910) whose real name was Samuel Langhorne Clements, was an American writer. He is best remembered as the man who gave the immortal characters of Tom Sawyer and Huckleberry Finn.

Meanings For Difficult Words

fence (n) : a structure that divides two areas of land, similar to a wall but made of wood or wire
pavement (n) : a flat part at the side of a road for people to walk on hollow
hollow (adj) : having a hole or an empty space inside an object
existence (n) : being real or living or of being present
ridicule (v) : make fun of somebody/something or make them look silly; mockery
magnificent (adj) : extremely attractive and impressive; deserving praise; splendid
resume (v) : begins again or continues after being interrupted
dreading (v) : to be very afraid of something; to fear that something bad is going to happen

AP State Syllabus AP Board 9th Class Physical Science Important Questions Chapter 10 Work and Energy

AP State Syllabus 9th Class Physical Science Important Questions 10th Lesson Work and Energy

9th Class Physical Science 10th Lesson Work and Energy 1 Mark Important Questions and Answers

Question 1.
What type of energies are possessed by the objects shown in below figures.
Answer:

i) Potential energy

ii) Kinetic energy

9th Class Physical Science 10th Lesson Work and Energy 2 Marks Important Questions and Answers

Question 1.
According to the scientific concept of the work, two conditions need to be satisfied in order to say that work has been done.
i. A force should act on the object.
ii. The object must be displaced or there must be change in position of the object. Now complete the table given below.

Situation been done or not	Whether work has	Reason to say that work has been done or not
A boy lifts his bag from the ground
A girl is trying to push a huge rock

Answer:

Situation been done or not	Whether work has	Reason to say that work has been done or not
A boy lifts his bag from the ground	done	1) Force acted on the bag. 2) Bag moved from the ground.
A girl is trying to push a huge rock	not done	1) Force acted on the huge rock. 2) Rock not moved.

9th Class Physical Science 10th Lesson Work and Energy 4 Marks Important Questions and Answers

Question 1.
Write the differences between potential energy and kinetic energy.
(OR)
Compare and differentiate between political energy and kinetic energy.
Answer:

Kinetic energy	Potential energy
1) K.E is the kind of energy present in a body due to the property of its motion.	1) P.E is the type of energy present in a body due to the property of its state.
2) It can be easily transferred from one body to another.	2) It is not transferable.
3) K.E = ½ mv2	3) PE = mgh
4) Flowing water is example of K.E.	4) Water present at the top of hill is an example of P.E.

9th Class Physical Science 10th Lesson Work and Energy Important Questions and Answers

9th Class Physical Science 10th Lesson Work and Energy 1 Mark Important Questions and Answers

Question 1.
What is meant by one joule work?
Answer:
1 joule work is the amount of work done on an object when a force of 1 Newton displaces it by 1 m along the line of action of the force.

Question 2.
What happens to the speed of a ball while it moves up with an initial velocity?
Answer:
As the ball moves up, the gravitational force acts against to the direction of motion of the object. Hence its velocity slowly decreases.

Question 3.
When a ball is moving up with an initial velocity, what will be its speed at its maximum height?
Answer:
The speed of a ball moving up is zero at its maximum height.

Question 4.
What happens to the speed of the ball during its downward motion?
Answer:
The speed of the ball during its downwards motion will increase gradually.

Question 5.
Define energy.
Answer:
Energy is defined as the capacity to do a work.

Question 6.
Why does a person get tired standing at a place for long time?
Answer:
Though the person standing is not doing any work externally a lot of work is being done inside the body.

The muscles of the body become stretched when he stands for long time and heart has to pump more blood to muscles. This leads to loss of energy inside the body and hence he gets tired.

Question 7.
What is kinetic energy?
Answer:
The energy possessed by an object due to its motion is called kinetic energy.

Question 8.
Write a formula to measure kinetic energy.
Answer:
KE = \(\frac{1}{2}\)mv²

Question 9.
Define potential energy.
Answer:
The energy possessed by an object because of its position or shape is called its potential energy.

Question 10.
Write a formula to calculate potential energy.
Answer:
Potential energy PE = mgh.

Question 11.
What is conservation of energy?
Answer:
The law of conservation of energy states that the energy can neither be created nor destroyed. It can only be changed from one form to another.

Question 12.
A battery lights a bulb. Describe the energy changes involved in the process?
Answer:
Chemical energy is converted into heat energy then light energy.

Question 13.
A mass of 10 kg at a point A on the table is moved to a point B. If the line joining A & B is horizontal, what is the work done on the object by gravitational force? Explain your answer.
Answer:
The work done on the object by gravitational force is zero, since the angle between force and motion of object is zero.

Question 14.
A person holds a bundle of hay over his head of 30 minutes and get tired. Has he done some work or not? Justify your answer.
Answer:
There is no displacement. So no work is done on the object. (W = F x s = F x 0 = 0)

Question 15.
Expand OTE.
Answer:
OTE means – Ocean Thermal Energy.

Question 16.
Expand OTEC.
Answer:
OTEC means – Ocean Thermal Energy Conversion.

Question 17.
What is ‘Biomass’?
Answer:
The material contained in the bodies of plants and animals is Called ‘Biomass’.

Question 18.
What is Nuclear reaction?
Answer:
The physical reaction which involves changes in nucleus of an atom is called “Nuclear reaction”.

Question 19.
What is Nuclear Energy?
Answer:
The energy released during a nuclear reaction is called nuclear energy.

9th Class Physical Science 10th Lesson Work and Energy 2 Marks Important Questions and Answers

Question 1.
Define power and mention its units.
Answer:
Power is defined as the rate of doing work or rate of transfer of energy.

The unit of power is ‘Watt’ and denoted by the symbol ‘W’.

Question 2.
What is the meaning of one joule?
Answer:
One joule is the amount of work done on an object when a force of 1 Newton displaces it by 1 m along the line of action of the force.
If F = 1N, s = 1 m then the work done
W = F × s = 1 N × 1 m = 1 N-m = 1 Joule

Question 3.
What is the meaning of one watt?
Answer:
1 watt is the power of an object, which does work at the rate of one joule per second.
If W = 1J, t = 1 sec then,

Question 4.
Explain work through a diagram.
Answer:

1. Suppose a constant force (F) acts on an object and is moved through a distance (s) along the direction of the force, as shown in figure.
2. Then the work done W = F × s

Question 5.
Certain force acting on a 20 kg mass changes it velocity from 5 ms-1 to 2 ms-1. Calculate the work done by the force?
Answer:
Mass (m) = 20 kg
Initial velocity (u) = 5 m/s
Final velocity (v) = 2 m/s

Change in kinetic energy stored as work done is – 210 J

Question 6.
The potential energy of a freely falling object decreases progressively. Does the violate the law of conservation of energy? Why?
Answer:
No, it is not violating law of conservation of energy because when freely falling object moves towards ground its speed increases due to gravitational force so potential energy is converted into kinetic energy.

Question 7.
Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/hr.
Answer:

∴ The work done to stop the moving car = 208333 J

Question 8.
An object of mass m is moving with a constant velocity v. tlow much work should be done on the object in order to bring the object to rest?
Answer:
Mass of the object = m, Velocity of the object = v, Kinetic energy = \(\frac{1}{2}\) mv².
The work done to bring the object to rest is stored in the from of kinetic energy.
∴ Work done = \(\frac{1}{2}\) mv²

Question 9.
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the long arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Answer:
i) In the first case force is acting perpendicular to the displacement of the object. So the work done by the force is zero.
ii) In the second case force is acting in the direction of displacement. So work done
by the force is positive.
iii) In the third case force and displacement opposite to each oth£r. So the work done is negative. –

Question 10.
What is Nuclear fission?
Answer:
1) The process in which heavy nucleus of a radioactive atom splits up into smaller nuclei when bambared with low energy neutrons is called nuclear fission.
2) Ex : ²³⁵U₉₂ + ¹n₀ → ¹³⁹Ba₅₆ + ⁹⁴Kr₃₆ + ³¹n₀ + Energy

Question 11.
What is nuclear fusion?
Answer:
1) The process which two nuclei of light elements combine to form a heavy nucleus is called nuclear fusion.
2) Ex : 2H₁ + 2H₁ → 3He₂ + ¹n₀ + Energy.

Question 12.
What is Ocean Thermal Energy?
Answer:

1. Heat from the sun is absorbed by the water on the surface of ocean, but at deeper levels of ocean, the temperature is very less.
2. So, there is temperature difference between the water “at the surface of ocean” and at “deep levels”.
3. This difference in temperature is called Ocean Thermal Energy.

9th Class Physical Science 10th Lesson Work and Energy 4 Marks Important Questions and Answers

Question 1.
Explain negative value of work done.
Answer:

1. Suppose a ball is moving on a plain ground, will get stopped after sometime due to frictional force acting on it in opposite direction.
   
2. If the force acting on an object and displacement are in opposite directions then the work done by the force is taken as negative.
   W = – F × s
3. If the work done has negative value, the body on which the work has been done loses energy.

Question 2.
Look at the activities listed below. Reason out whether or not, work is done in the light of your understanding of the term work.
1. Suma is swimming in a pond.
2. A donkey is carrying a load on its back.
3. A wind-mill lifting water from a well.
4. A green plant is carrying out photosynthesis.
5. An engine is pulling a train.
6. Food grains are getting dried in the sun.
7. A sail boat is moving due to wind energy.
Answer:

1. Work is done because force is applied and the person is moved.
2. No work is done the object is not moved in the direction of force.
3. Work is done against gravitational force thrift water.
4. No work is done
5. Work is done since the engine is pulling the train.
6. No work is done.
7. Work isjdone because sail boat is moving in the direction of wind energy.

Question 3.
An object of mass 4 kg is raised to height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half way down.
Answer:
m = 4 kg, h = 5 m, g = 10 m/s².
Potential energy = mgh = 4 × 10 × 5 = 200 J.
If object is allowed to fall, then we have to take half of distance.
u = 0, h = 2.5 m, a = + g = 10 m/s²
v² — u² = 2gh ⇒ v² = 2 × 10 × 2.5 ⇒ v² = 50

∴ At half of distance the kinetic energy = 100 J.

SCERT AP 7th Class English Government Textbook Answers 5th Lesson The Art of Weaving Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 5 Questions and Answers The Art of Weaving

7th Class English Unit 5 The Art of Weaving Textbook Questions and Answers

Look at the following picture and answer the questions that follow.

Question 1.
Have you seen any of these in your locality/place?
Answer:
Yes, I have seen this kind puppets in my primary school.

Question 2.
How do they make these puppets?
Answer:
They make these puppets with sticks, ropes, paper, cardboards, etc.

Question 3.
Have you ever tried any craft?
Answer:
No, I have never tried any craft.

Question 4.
Are there any craftsmen/craftswomen in your village/area?
Answer:
Yes, there are some craftsmen in our village. There are people who work on Embroidery, Knitting, Lace-making, Woodcraft, Pottery, Jewellery, etc.

Question 5.
What art/craft do you like the most?
Answer:
I like woodcraft and pottery most.

Reading Comprehension

A. Answer the following questions.

Question 1.
What is the specialty of a Mangalagiri saree?
Answer:
The Nizam design is a unique characteristic feature of Mangalagiri saree. The uniqueness of Mangalgiri cotton is because of its durability. The body and the pallu is embellished with zari or golden thread work with a Nizam border and geometrical and simple designs.

Question 2.
Explain what the warp and the weft are.
Answer:
The warp is the vertical thread and the weft is the horizontal thread.

Question 3.
Why do the weavers perform street-sizing?
Answer:
Street-sizing is the extension of the warp, spraying of starch and brushing followed by drying to get the fabric ready.

Question 4.
What problems do the weavers of Mangalagiri face?
Answer:
The weavers face many problems in the textile industry. They face tough competition, change in fashion, trends, scarcity of raw material and the involvement of middle men.

Question 5.
Are the handloom fabrics expensive? Why?
Answer:
Weaving fabric on a hand loom is more expensive than that of a power loom because the fabric is woven manually.

B. Arrange the following sentences in sequential order and write them in the space provided.

1) The yarn is kept in the sunlight for drying.
2) The street sizing process is done to make the thread thick and strong.
3) The yarn is boiled and sent for dyeing.
4) The yarn is rolled on an iron rod and fixed on a loom to weave.
5) The yarn bundles are placed on spinning wheel.
Answer:
3) The yarn is boiled and sent for dyeing.
5) The yarn bundles are placed on spinning wheel.
2) The street sizing process is done to make the thread thick and strong.
1) The yarn is kept in the sunlight for. drying.
4) The yarn is rolled on an iron rod and fixed on a loom to weave.

C. Read the following statements and say whether they are true or false.

1) Power lev ms are more expensive than handlooms. [ ]
2) Warp and weft is an interlacing method of weaving. [ ]
3) Warp refers to horizontal threads on woven cloth. [ ]
4) Nizam border is a unique feature of Mangalagiri saree. [ ]
5) Mangalagiri is a small town in Vijayawada district. [ ]
Answer:

1. False
2. True
3. False
4. True
5. False

Correct the false statements and write them here :
1) ……………………………………….
2) ……………………………………….
3) ……………………………………….
4) ……………………………………….
5) ……………………………………….

Correct the false statements and write them here:
1) Handlooms are more expensive than power looms.
3) Warp refers to vertical threads on woven cloth.
5) Mangalagiri is a small town in Guntur district.

Vocabulary

A. Match the following words denoting their profession or trade.

1. A person who makes pots	a. tinker
2. A person who weaves fabric	b. sculptor
3. A person who goes from place to place to mend pots, pans, etc.	c. florist
4. A person who makes furniture	d. potter
5. A person who carves stones into idols	e. carpenter
6. A person who sells flowers	f. weaver

Answer:

1. A person who makes pots	d. potter
2. A person who weaves fabric	f. weaver
3. A person who goes from place to place to mend pots, pans, etc.	a. tinker
4. A person who makes furniture	e. carpenter
5. A person who carves stones into idols	b. sculptor
6. A person who sells flowers	c. florist

B. Read the following:

Today I helped my mom in the kitchen. I carefully cut the vegetables and my mom slowly placed them into a boiling pot of water. Next, mom quickly browned the onions while I patiently peeled off the potatoes. Immediately, my mom deeply fried the potatoes also. 1 eagerly waited for my nqxt job, which was to gently sprinkle spices into the vegetable soup. But I accidentally poured too much cumin. I quietly told my mom my mistake, and she sweetly told me that, initially, we made such mistakes. Gradually, you would be out of confusion.

In the above event, there are many words ending in ly. They are adverbs. They are formed by adding ‘ly’ to adjectives.
Adjective + ly = Adverb

E.g : approximate + ly

Identify the adverbs from the paragraph given above and write them in the space given.

Answer:

Look at the following image and make adverbs by adding ‘ly’. One is done for you.

Answer:

1. happily
2. angrily
3. greatly
4. quickly
5. broadly
6. cleanly
7. beautifully
8. colourlessly

C. Let’s learn some idioms to express ‘happiness’.

Use these idiomatic expressions in your own sentences. One is done for you.
E.g. I have been over the moon when I got gold medal in the National Athletics.
1. ……………………………………….
2. ……………………………………….
3. ……………………………………….
4. ……………………………………….
5. ……………………………………….
Answer:
1. walking on air:
Answer:
After the delivery of her baby, she was walking on air.

2. happy camper:
Answer:
There are no happy campers after the COVID-19.

3. jump for joy:
Answer:
We exactly jump for joy after our results.

4. have stars in your eyes:
Answer:
When she left the school, she had stars in her eyes.

5. on top of the world:
Answer:
She felt on top of the world when she was elected in the elections.

Grammar

A. Read the following sentences from the text:
One of us enquired, “Sir, what are you doing?”
He replied, “I am weaving a saree on the loom.”

Observe the verb in the sentence. It is in present progressive tense. It denotes the ‘on going’ actions.

Present Continuous tense / Progressive tense :

When Mary visits Kavya’s home to play, Kavya, her brother Naveen, and her neighbour Bibi are working in the garden.

Read the conversation among them.
Mary : Hello! Friends, what are you doing here?
Kavya : I’m digging a pit, Mary.
Naveen : I’m clearing the clay from the pit.
Mary : What are you plucking Bibi ?
Bibi : I’m plucking weeds in the garden.
Mary : Why are you digging the pit?
Kavya : We are planning to grow a rose plant here.
Mary : You are doing a very good job. Keep it up.

You might have noticed the use of present progressive tense in the above conversation.
Look!, Hear!, See!, Watch!, Listen!, etc. are generally used in present continuous tense.

Ex : Look ! I’m drawing.
See ! how the peacock is dancing.
Listen! I’m talking to you.

1. Frame as many sentences as you can from the following table.

a) …………………………………………..
b) …………………………………………..
c) …………………………………………..
d) …………………………………………..
e) …………………………………………..
Answer:

1. I am making sweets for me.
2. We are writing English homework.
3. You are not writing English homework.
4. He is folding cloth on handloom.
5. She is not weaving sarees in the room.
6. She is not cutting sweets for me.
7. They are boiling water in the pot.
8. I am not boiling water in the pot.
9. We are not folding cloth on the handloom.
10. He is not cutting sweets for me.
11. She is not making sweets for me.
12. They are writing English homework.
13. You are boiling water in the pot.
14. I am not weaving sarees in the room.
15. We are not making sweets for me.

2. Write meaningful sentences using present continuous tense with the sets of words given.
a) butterflies- fly- garden ……………………………………………………
b) dogs – run – street ……………………………………………………
c) baby – crawl- floor ……………………………………………………
d) boy – dance – stage ……………………………………………………
e) girl – paint – picture ……………………………………………………
Answer:
a) Butterflies are flying in the garden,
b) Dogs are running in the street,
c) A baby is crawling on the floor,
d) A boy is dancing on the stage.
e) A girl is painting a picture.

B. Reported Speech

Look at the following sentences from the lesson.
1. Ramaiah, a weaver, greeted with a smile and replied, “We are street-sizing.”
2. He replied, “I am weaving a saree on the loom. ”

The part of the sentence that is kept within the inverted commas is the sentence actually spoken by the speaker. So, the above sentences are said to be in Direct Speech.

When the same sentences are told by someone other than the speaker they are said to be in Indirect speech (Reported Speech).

e.g. 1. Ramaiah, a weaver, greeted with a smile and replied that they were street-sizing.
2. He replied that he was weaving a saree on the loom.

Let’s observe the underlined words in the above sentences.
“that” is used as conjunction.

‘are’ in the sentence (1) has become ‘were’ and ‘am weaving’ in the sentence (2) has become ‘was weaving’.

Pronoun ‘we’ in the sentence (1) has become ‘they’.
‘I’ in the sentence (2) has become ‘he’.

Now, read the following conversation and complete the passage that follows.

The weaver :
Along with 5 persons, I have to work in each stage to weave a saree.

The students :
We are very happy to learn from you.

The weaver told the students ________ along with 5 to 6 persons ________ had to work in each stage to weave a saree and the students replied him _____, ____ were verv hannV to learn from him.
Answer:
The weaver told the students that along with 5 to 6 persons he had to work in each stage to weave a saree and the students replied him that they were very happy to learn from him.

C. Observe the position of the objects/things in the given picture.

Now, Read the following sentences. Tick (✓) the suitable preposition.
1. The fridge is in between/among the door and the clock.
2. The clock is before / on the wall.
3. The car is before/under the table.
4. The chair is placed against/before the table.
5. The books are on / in the shelf.
Answer:

Writing

Go through the following invitation card.

Now, prepare an invitation card for a handicraft exhibition cum sale.

(Items of display: handloom fabrics, mats, designing pots, clay dolls, wall hangings etc., – 29-7-2021 -10.00 am to 5.30 p.m. – free entry- District Handloom Cooperative Society-by Homage to Heritage Association, Andhra Pradesh)

Talking Time

1. Role-play:
Jaya : Hallo! What are you doing?
Riya : I’m getting ready for the party.
Jaya : Oh! Really, How are you going there? .
Riya : Hmmm! We are going there by car.
Jaya : I see. Are your children coming?
Riya : Yes. They are coming.
Jaya : I am also planning to bring my children.
Riya : Oh! Very nice. Meet you there. Bye.

Language Function :
Here is a conversation between two friends in the classroom.

Raheem : Good morning, Shyam! Are you searching for something?
Shyam : You are right. I am searching for my English notebook.
Raheem : You gave it to our English teacher yesterday, didn’t you?
Shyam : Oh, My goodness! You have also given your notes, haven’t you?
Raheem : Yes, Bobby has given my notes to the teacher, hasn’t he??
Shyam : Okay. We shall collect them from our teacher, shan’t we?

In the above conversation ‘didn’t you’, ‘haven’t you’, ‘hasn’t he’, ‘shan’t we’ are tag questions. Tag questions are used to get confirmation.
Eg: Monika is a good girl, isn’t she?

I. Fill in the blanks with suitable question tag given in the box.

1. You like chocolates, _________ ?
2. She is amazing, _________ ?
3. You can’t sing, _________ ?
4. You are my best friend, _________ ?
5. I’m a good boy, _________ ?
6. They are reading books, _________ ?
7. My father doesn’t cook well, _________ ?
8. He wasn’t listening, _________ ?

Answer:

1. You like chocolates, don’t you?
2. She is amazing, isn’t she?
3. You can’t sing, can you?
4. You are my best friend, aren’t you?
5. I’m a good boy, aren’t I?
6. They are reading books, aren’t they?
7. My father doesn’t cook well, does he?
8. He wasn’t listening, was he?

Read the words aloud :
Identify the silent letters in the following words while your teacher is reading them aloud.

Answer:

Study Skill

Read the bar diagram carefully and answer the following questions.
HANDICRAFTS EXPORT
Source : Ministry of Textiles (Rs. in Crores)

1. What is the bar diagram about?
Answer:
The bar diagram is about Handicrafts Export.

2. What is the source of the information?
Answer:
Ministry of Textiles.

3. How many financial years are covered?
Answer:
Seven (7)

4. The export value was the highest in ( C )
A) 1990-91
B) 2000-01
C) 2002-03
Answer:
C) 2002-03

5. The observed trend for exports is ( A )
A) always increasing
B) always decreasing
C) neither increasing nor decreasing
Answer:
A) always increasing

Project

Design an advertisement for a cloth showroom.
Details to be included :
1. Name of the shop.
2. Items sold.
3. Address and contact information.
4. Tag line.
5. Sale offers (Discounts).
Answer:

Fun Time

Prepare a door-mat using old pieces of cloth, wool, fur, coir, etc. available in your surroundings.
Answer:
Doormat making from old clothes :

Step 1 :
First cut and open the Lungi. It will be about 6 ft long after cutting. The width is about 4 ft. Cut 3 inch wide strips from it. You can cut about 12 strips of 6 ft long each from this cloth.

Step 2 :
Take 3 strips in hand and tie them together at one end. Insert all three tied end of strips in the door or window grill.

Step 3 :
Tightly braid the three strips of cloth starting from the tied end. It is same as braiding hair. You can add another strip in the braid when the length of strip being braided reaches the end. After using all 12 strips you will have a 20 ft long braided length of cord.

Step 4 :
Trim the excess length of strip at end. Using the needle and thread, stitch the ends of all three strips in the braid together. Cut the ends tied with window grill and sew those ends also together.

Step 5 :
Start rolling from one end, roll the braided coil in circles to form the mat. Using a needle with dark coloured yarn, stitch the roll continuously with adjacent circle while rolling.

Step 6 : Continue to roll the coil as well. Continue stitching the rolled mat with the adjacent coil. Once you completed rolling of all 20 ft long coil, stitch the end with the mat and finish.

Now, the doormat is ready.

Language Game

Fill in the blanks with suitable spellings. One is done for you.
1. art (creative work, skill)
2. part (portion or piece)
3. chart (used for drawing a big picutre)
4. oxcart (a cart that is drawn by an ox)
5. restart (starting an engine again)
6. outsmart (beat through cleverness)
7. flowchart (process of diagram)
8. sweetheart (dearest to heart)

Listening

Listen to the following announcement made in an exhibition. Fill in the table given below.

Good evening to everybody. Warm welcome to all of you to this Sunday’s special programme. This is Vamsi welcomes you all to the Dum Dum Exhibition. This exhibition will be open from 4 p.m to 8 p.m. every day.

The visitors are requested to get their tickets from the counter. It is on the right to the Halloween corner. Each ticket costs Rs. 50/- and a family ticket is Rs. 200/-. There is a refreshment stall opposite to the ticket counter.

We have some special attractions : a motor cyclist in the well, a giant wheel, per-forming parrots, shooting galleries, many handicrafts and handloom fabrics. The show will run only for four more days. Request all your friends and relatives to visit this exhibition without fail.

Fill in the table as you listen.


Answer:

The Art of Weaving Summary

One day an English teacher took the class for a case-study to Mangalagiri, a famous town for handicraft weaving in Guntur District. The case-study is about weaving industry.

The students tried to know many things about the weaving industry in Manglagiri with the help of a master weaver named Veeraiah.

Mr. Veeraiah explained to them how they make the yarn suitable for dyeing. After dyeing it is washed, dried at room temperature and brought for the process of spinning. Later yarn spools are made ready for making a fabric.

A weaver named Ramaiah took the students and showed them an open area where the yarn was spread. Another weaver Sambayya explained to them that the uniqueness of Mangalagiri cotton is because of its durability. He said that they weave sarees, dress materials, kurtas, dupattas and shirts. It has a rich appearance. The quality of work done by the weavers and the pain the weavers take for weaving a saree keep the love for our Mangalagiri fabric.

Around 5000 weavers are working in the Mangalagiri textiles industry in a population of eighty thousand. Mangalagiri has a special place in the world textile map because of the handloom sarees and the dress-materials woven here are world famous.

The weavers face many problems in the textile industry. They face tough competition, change in fashion, trends, scarcity of raw material and the involvement of middle men. However the traditional value of handloom fabric is increasing for their uniqueness. Handloom fabric, thus, has a lot of global demand because of its artistic appeal.

Meanings For Difficult Worps

fabric (n.) : cloth or other material
occupation (n.) : a job or profession
migration (n.) : movement from one region to another
hank (n.) : coil or yarn bundle
warp (n.) : vertical thread
radiance (adj.) : glowing brightly or shining
extension (ta.) : stretching out
knotting (v.) : tying
enthusiasm (n.) : keen interest
evidently (adv.) : in a way that is seen or understood
durability (n.) : permanence
geometrical (adj.) : decorated with regular lines or shapes
distinguish (v.) : differentiate or identify
dobby (n.) : a mechanism attached to a loom for weaving small patterns
expensive (adj.) : costly

Indian Weavers Poem

WEAVERS, weaving at break of day,
Why do you weave a garment so gay?…
Blue as the wing of a halcyon wild,
We weave the robes of a new-born child,
Weavers, weaving at fall of night,
Why do you weave a garment so bright?
Like the plumes of a peacock, purple and green,
We weave the marriage- veils of a queen.
Weavers, weaving solemn and still,
What do you weave in the moonlight chill?
White as a feather and white as a cloud,
We weave a dead man’s funeral shroud. – Sarojini Naidu

Appreciation of the poem

I. Match the rhyming words and write them in the blanks given :
1. day – a. queen
2. wild – b. bright
3. night – c. gay
4. green – d. shroud
5. still – e. child
6. cloud – f. chill
Answer:
1. day – (c) gay
2. wild – (e) child
3. night – (b) bright
4. green – (a) queen
5. still – (f) chill
6. cloud – (d) shroud

II. Choose the correct answer:
1. What do the weavers weave in the early morning?
a) a bright blue cloth
b) a dull grey cloth
c) a soft white cloth
d) a red coloured cloth
Answer:
a) a bright blue cloth

2. The is purple and green coloured.
a) dress of the weaver
b) dress of the new born child
c) queen’s marriage veil
d) robe of the king
Answer:
c) queen’s marriage veil

3. What do the weavers weave in the chilly moonlight?
a) a garment light as feather
b) a garment meant to cover the dead man
c) a garment to keep away the chill
d) a garment to warp a new born child
Answer:
b) a garment meant to cover the dead man

4. The weavers weave at the fall of night.
a) funeral shroud
b) a garment so bright
c) robes of a new born child
d) a carpet
Answer:
b) a garment so bright

5. The bright garment is compared to
a) the stripes of a tiger
b) the wing of a parrot
c) the feathers of a peacock
d) the rainbow
Answer:
c) the feathers of a peacock

6. Whom does the poetess address in the poem?
a) the children
b) the queen
c) the weavers
d) all the above
Answer:
c) the weavers

III. Answer the following questions.

Question 1.
Why are the weavers solemn and still?
Answer:
The weavers are solemn and still because they are weaving a dead man’s funeral shroud.

Question 2.
What are the three events of life depicted in the poem?
Answer:
Birth, marriage and death are the three events referred to in this poem. These events indicate the three stages of human life – childhood, youth and old age.

Question 3.
Pick out the three types of cloth in the poem.
Answer:
The three types of cloths are (1) cloth for a new-born baby (2) cloth for the veils of a queen and (3) cloth to cover the dead body.

Question 4.
Why is white coloured cloth used for the funeral?
Answer:
The cloth is used to cover the dead body.

Question 5.
What colours do the weavers weave for the queen’s veil?
Answer:
The weavers weave purple and green colours for the queen’s veil.

Check Point

Indian Weavers Summary

Indian Weavers by Sarojini Naidu is a short poem consisting of three stanzas having four lines each.

The poetess talks about three types of dresses that the Indian Weavers weave at three particular times of the day. Metaphorically each time and the dress weaved in that time symbolizes a particular stage of life.

The poetess uses a number of literary devices to express her ideas like simile, metaphor, etc. The poem also consists of a discussion between the poet and the weavers; the poet asks the weavers and the latter reply.

STANZA 1 :
In the first stanza, the poetess questions the weavers that why are they weaving clothes early in the morning that seem to be quite beautiful and charming and of a particular colour. The poetess is curious to know about these clothes as they seem quite special. The weavers reply that the clothes that they are weaying are blue as the wing of a halcyon which is the other name of the kingfisher whose wings are bright blue in colour. The weavers reply that they are weaving the robes of a new-born child who has just come to the world. This stanza describes the first stage of human life which is full of freshness, happiness, beauty and hope and there is no place for sorrow at this stage.

STANZA 2 :
In this stanza, the poetess meets the Indian weavers again during the fall of night and asks why they are weaving a cloth late in the evening which is the time when most of the Indian marriages take place. She also asks why they are weaving a garment so bright like the plumes (feathers) of a peacock, purple and green. The weavers reply that the cloth is bright and richly coloured because they are weaving it for a queen. She will use it to make her marriage veil. This stanza describes the second or adult stage of life when humans quest for a better and prosperous life. The colours purple and green symbolize the ups and downs of the life that makes adulthood bright.

STANZA 3 :
In the final stanza, the poetess finds the weavers quite sorrowful, grieved and silent. They are weaving something weird in the dead of the night which is colourless and lifeless so, rather than asking why are they weav-ing, she asks what are they weaving? The weavers reply that they are weaving shroud which means a cloth used to put on the dead body. This represents the final stage of human life that is death which is lifeless and emotionless just like a white cloud or a feather. However, the white colour also symbolizes eternal peace and calm that comes with death.

The poem sums up human life in three main stages using symbols like clothes and times of the day. The life starts its journey with blue colour representing joy and hap-piness and then come green and purple that represent the ups and downs of life along with happiness and finally comes a single colour – white that represents the last stage of human life when the person dies and with him the emotions that were connected to life die as well.

Poectic Devices Used In The Lines

1. Weavers, weaving at break of day.
Alliteration – The sound of letter “w” is repeated- Weavers, weaving
Metaphor – The birth (childhood stage of man) is implicitly compared with a break of day.

2. Why do you weave a garment so gay? …
Alliteration – The sound of letter “g” is repeated- garment so gay

3. Blue as the wing of a halcyon wild.
Alliteration – The sound of letter “w” is repeated- wing of a halcyon wild
Simile – The blue coloured cloth is directly compared with a wing of wild halcyon.

4. We weave the robes of a new-born child.
Alliteration – The sound of letter “w” is repeated- We weave

5. Weavers, weaving at fall of night.
Alliteration – The sound of letter “w” is repeated- Weavers, weaving
Metaphor- Adulthood (young – the second stage of man) is implicitly compared with the fall of night.

6. Why do you weave a garment so bright?
Alliteration – The sound of letter “w” is repeated.

7. Like the plumes of a peacock, purple and green.
Simile – The garment is directly compared with purple and green coloured plumes of peacock.
Alliteration – The sound of letter “p” is repeated- plumes of a peacock, purple

8. We weave the marriage-veils of a queen.
Alliteration – The sotind of letter “w” is repeated- We weave

9. Weavers, weaving solemn and still.
Alliteration – The sounds of letters “w” and “s” are repeated- Weavers, weaving

10. What do you weave in the moonlight chill?
Alliteration – The sound of letter “w” is repeated.
Metaphor – death (old age – the third and last stage of man’s life) is implicitly compared with moonlight.

11. White as a feather and white as a cloud.
Simile – The garment is directly compared with a feather and a cloud.

12. We weave a dead man’s funeral shroud.
Alliteration – The sound of letter “w” is repeated.

13. White as a feather and as a cloud.
We weave a dead man’s funeral shroud.
Simile – funeral shroud is directly compared with a feather and a cloud.

Indian Weavers About the Poet

Sarojini Naidu, the Nightingale of India was born on 13th February 1879 in Hyderbad. She is an Indian Independence activist, politician, a renowned orator and accomplished poet. She was elected as the first President of the Indian National Congress. Sarojini Naidu as a poet belongs to an era of struggle, slavery and freedom fighting. The poem Indian Weavers, one of her poems, explains different stages of life.

Meanings For Difficult Words

weaver (n) : a person who weaves fabric
gay (adj) : (here) brightly coloured
halcyon (n) : a tropical Asian and African kingfisher with brightly coloured plumage
break of day (phr.) : early morning
garment (n) : a single item of clothing
robe (n) : a long loose outer garment
fall of night (phr.) : late in the evening
veil (n) : a piece of material owned by a woman to protect face
plume (n) : a long soft feather or arrangement of feathers
solemn (adj) : deeply serious
funeral (n) : a ceremony to honour a deceased person
still (adj) : quiet
shroud (n) : a cloth for the dead

SCERT AP 7th Class English Textbook Answers 8th Lesson Gurajada – The Legend Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 8 Questions and Answers Gurajada – The Legend

7th Class English Unit 8 The Gurajada – The Legend Textbook Questions and Answers

Go through the banner/poster and answer the questions that follow :

Question 1.
What is the banner about?
Answer:
The banner is about the celebrations of Telugu Language Day.

Question 2.
Why do we celebrate such days? Discuss.
Answer:
We celebrate such days in memory of great people / great events.

Question 3.
Mention some names who contributed to the society through their literature.
Answer:
Gurajada Apparao, Tagore, Gurram Jashuva, Sarojini Naidu, Gidudu Rama Murthy, Sri Sri, etc.

Question 4.
Name some writings that influence our society.
Answer:
Kanyasulkam by Cmrajada Apparao, Vemana Satakam by Vemana, Rajashekara Charitramu by Kandukur Veeresalingam, etc.

Question 5.
Do you know any Telugu writer who brought changes in the society through his/her writings?
Answer:
Srirangam Srinivasa Rao was the first true modern Telugu poet to write about contemporary issues that affected the day-to-day life of a common man. He wrote ‘Mahaprasthanam’.

Questions Given In The Lesson

Possible answers to the questions given in the middle and at the end of the lesson:

Question 1.
How do you feel when you meet great people?
Answer:
I feel proud and happy when 1 meet great people.

Question 2.
Do you preserve the letter or appreciation from anyone you love most?
Answer:
Yes, I love to preserve the letter or appreciation from anyone I love most.

Reading Comprehension

A. Answer the following questions in two or three sentences.

Question 1.
What works did Gurajada do to promote the spoken dialects?
Answer:
Kanyasulkam and Prataparudreeyam

Question 2.
Why did Gurajada meet Rabindranath Tagore? Why was the meeting special?
Answer:
Syamendra Mohandas from Calcutta asked Gurajada to introduce a suitable style in the languages used by people in Bengali. In this connection, Gurajada met Rabindrnath Tagore two times in 1912.

Question 3.
Which work of Gurajada did attract Tagore ? (or) Which work of Gurajada attracted Tagore?
Answer:
‘Sarangadhara’ (classical literature) written by Gurajada attracted Tagore.

Question 4.
Mention the significance of the year 1911.
Answer:
The year 1911 is significant in the history of modern Telugu literature as the move¬ment for spoken dialect was started by Gidugu and Gurajada.

Question 5.
Why did Viswakavi write a letter to Mahakavi?
Answer:
They have some similar ideology regarding the use of language in writing literature.

Question 6.
Who translated Gurajada’s “Desabhakthi” poems?
a) Gidugu Rama Murthy
b) Tagore
c) Sri Sri
Answer:
c) Sri Sri

Question 7.
What did Syamendra Mohandas appeal to Gurajada?
a) To write some books in Bengali.
b) To translate the works of Tagore and Bunkim.
c) To introduce a suitable style in Bengali vernacular language.
Answer:
c) To introduce a suitable style in Bengali vernacular language.

B. Put the following sentences in the order of events.

1. Gurajada was invited to attend the meeting of the Bangeeya Sahitya Parishad at Kolkata.
2. Madras University honoured him with the title “Emeritus Fellow”.
3. Rabindranath Tagore wrote a reply letter to Gurajada from Himalayas.
4. Gurajada met Rabindranath Tagore to discuss the importance of vernacular language.
5. Gurajada wrote an article on the experiences and impression of his meeting with Tagore.
Answer:

1. Gurajada was invited to attend the meeting’ of the Bangeeya Sahitya Parishad at Kolkata.
2. Madras University honoured him with the title “Emeritus Fellow”.
3. Rabindranath Tagore wrote a reply letter to Gurajada from Himalayas.
4. Gurajada met Rabindranath Tagore to discuss the importance of vernacular language.
5. Gurajada wrote an article on the experiences and impression of his meeting with Tagore.

C. State whether the following statements are true or false.

1. Gurajada Apparao could not meet Tagore.
2. Gurajada started Sahitya Parishad and promoted the traditional language.
3. Gidugu Ramamurthy and Gurajada were the principal members to introduce spoken dialects.
4. Gurajada and Tagore were the contemporaries.
5. Gurajada’s work for classical literature attracted Tagore.
Answer:

1. False
2. False
3. True
4. True
5. True

Vocabulary

A. Choose the word with similar meaning (synonyms) for the underlined words from the list given below

1. Guraiada’s style of writing is clear.
2. Gurajada is one of the greatest personalities from Andhra Pradesh.
3. Desabhakti’ is simple in language but excellent in thought.
4. The NDRF team saved many lives during the floods.
5. Telugu is spoken in different slangs.
Answer:

1. lucid
2. legendary
3. sublime
4. rescued
5. dialects

1. Read the following sentences :
a) Be regular in attending classes. You will miss a lot if you are irregular. (in the above sentence “irregular” is the antonym of the word “regular”)
b) The children must obey their parents. They must not disobey them.

Here the antonym is formed by adding ‘dis’ to the word ‘obey’. We can form antonyms by adding certain prefixes to the words.

Fill in the blanks with the antonyms of the underlined words.
1. Don’t be ………………. Only responsible citizens can create wonders.
2. You should be very patient enough to achieve success. If you are ………………., you may not reach your goals.
3. Stars are visible during night and ………………. during day.
4. Nothing is ………………. So, work hard to make anything possible.
5. An efficient person can get a job easily but an ………………. person cannot.

Grammar

The Simple Past and Past Perfect Tenses

Let us observe the following sentences :
Gurajada retired in 1913.
Gurajada met Rabindranath Tagore at latter’s residence on two occasions in 1912.
In the above sentences, the words ‘retired’, ‘met’ denote completed actions. These actions are said using past form of the verb.

Simple Past Tense
Usually, verbs in simple past are used to denote the actions completed in the past with the time mentioned.
E.g. 1. Tagore wrote a letter to Gurajada in 1914.
2. We visited Kashmir last year.
3. They worked with the same spirit to preserve vernacular languages in those days.

Now, let’s consider the following sentence from the text:

After Gurajada had visited Tagore, he wrote an article on the experiences and im-pression of their meeting.

Action 1 : Gurajada visited Tagore.
Action 2 : Gurajada wrote an article.

Both the actions took place in the past. But the action 1 took place before action 2. In such cases the action 1 is said by using past perfect tense and action 2 is said by using simple past.

Let’s see one more sentence from the text.

Syamendra Mohandas had written to Gurajada before he left Vizianagaram.

Here are some more examples :
1. Vissu had taken breakfast before he went to school.
2. After I had completed my project, my father arrived.

Exercise: Fill in the blanks with the right form of the verb given in the brackets.

1. The doctor ______ (leave) before the patient ______ (arrive)
2. After the fire ______ (start), people ______ (rush) out of the building.
3. I ______ him yesterday. (meet)
4. I ______ (recognize)him immediately as I ______ (see) him.
5. Long before the chief guest ______ (arrive), the rain ______ (stop).
Answer:

1. had left, arrived
2. had started, rushed
3. met
4. recognized, had seen
5. arrived, had stopped

Writing

A. Book Review:

Read the following:
Book Review of ‘Kanyasulkam’.
Physical features (Get up) :
Title of the Book : Kanyasulkam in Telugu
Writer of the book : Sri Gurajada Apparao
Quality of Paper: Good
No. of pages : 280 pages
First Published : 1892; Telugu
Publishers : 2007 in English, Indiana University Press. 248 pages.

Important Points:

• The book reflects social issues of the late 19th century.
• It supports the widow remarriage.
• It educates the disadvantages of child marriages.
• It tries to stop the marriages in which the girls of tender age are sold to the old persons.
• The title itself shows the evil, Kanyasulkam.
• The influence of book is still in the society.

B. Diary Entry:

Imagine that you got The Best Actor Award for your performance in the skit in the district level competitions conducted oh the occasion of the International Mother Language Day. Now, make an entry in your diary.
Answer:

Monday 22nd February Dear Diary,Yesterday was a great day in my life. My performance as an actor was recognized on a big platform. I received The Best Actor Award for my performance in the skit ‘Kanyasulkam’ in the district level competitions conducted on the occasion of the International Mother Language Day. I played the role of Girisam very well. Many of my friends, the members of my family, my teachers and classmates watched the skit and appreciated me for my performance after the skit was over. My teachers said that I would get the best actor award. It became true in a few hours. It was a memorable day in my life. Thank God. Karthik

Talking Time

1. Role-play:

Read the following conversation and note the underlined expressions which we use for apologizing.

Sunny : I am sorry, I have damaged your watch.
Bunny : It was a gift from my father. I wish you were more careful with it.
Sunny : Believe me, I am not careless. It was raining when I was returning home yesterday.
I wanted to protect it from the rain. The watch slipped from my wrist and got damaged. I am extremely sorry.
Bunny : Oh ! It was an accident then. Never mind.
Sunny : That is so nice of you. You are very kind-hearted. Thank you.
Bunny : It’s all right.

Language Function:
Giving advice

Read the following sentences.
1. You should get up early.
2. You should not eat junk food.
3. You should not walk in the middle of the road.
4. You should obey your parents.

Observe the following table:

Using the table above give an advice to your Mend. E.g. You should wear mask.

1. You should maintain social distance.
2. You should clean your hands with sanitizer.
3. You should not touch your eyes, nose and mouth.
4. You should not get close contact with a sick person.
5. You should cough and sneeze in your hands.
6. You should limit your social gatherings.

Listening

Listen to the following story and answer the questions.

LAL BAHADUR SHASTRI’S HONESTY
When Lai Bahadur Shastri was the Prime Minister of India, he went to a textile mill. He requested the owner of the mill to show him cheaper sarees for his wife. The owner showed him some exquisite sarees. When Shastri ji asked the price, he felt they were very expensive. He asked for cheaper sarees. The owner showed him cheaper sarees. But, shastri ji still found them expensive. The owner was surprised and requested not worry about the prices. And he told Sastri ji that it would be his previlege to give the sarees as gift for he was the prime minister of india.

Shastri Ji replied that he could not accept such expensive gifts and he would only take a saree that he could afford.

Answer the following questions:
1. What is this story about?
Answer:
This story is about Lai Bahadur Shastri’s honesty

2. Where did Sastryji go?
Answer:
To a textile mill

3. What did he want to buy for his wife?
a) a saree
b) a gold chain
c) a purse
Answer:
a) a saree

4. The owner of the textile mili showed very expensive sarees. Tick whether this statement is true or false. (True / False)
Answer:
True

5. Did Shastriji accept sarees free as a gift?
Answer:
No.

Gurajada – The Legend Summary

Gurajada Apparao was a legendary personality among the Telugu people. He was a social reformer and a revolutionary poet and writer. He used the language of common people in his writings. He had a strong faith in spoken Telugu.

Gurajada woke up the readers to fight the social evils. He dreamt of a new social system. He fought for women’s education, social equality and widow re-marriages.

Being inspired by Gurajada’s literary work, The Bengal Literary Association invited him to attend a meeting at Calcutta. Syamendra Mohandas from Calcutta asked Gurajada to introduce a suitable style in the languages used by people in Bengali. In this connection, Gurajada met Rabindranath Tagore two times in 1912. Tagore wrote an article on the experiences and impression of his meeting with Gurajada.

Gurajada used noble, simple, clear and powerful words to express his straight forward ideals. Gurajada and Tagore were in constant touch with each other. They wrote letters each other. He passed away on 30th November 1915 leaving behind the legacy of immortal literature for future generations. No library is complete without the works of the legendary writer Gurajada.

Meanings For Difficult Words

legendary (adj) : very well known
immortal (adj) : living for ever
revolutionary (adj) : causing a complete change
harbinger (n) : who foreshadows the future events
scholar (n) : a learned person
disciple (n) : a follower to learn something
abundantly (adv) : plentifully; in a sufficient dgree
idealize (v) : to regard something as ideal
rescued (v) : saved from danger
dialect (n) : a particular form of a language of a region or a group
significant (adj) : notable; important
vernacular (n) : language of common people
vernacular (adj) : (of language) spoken by common people
sublime (adj) : of great excellence or beauty
lucid (n) : clear
immortal (adj) : that lives or lasts for ever

Nails in the Fence

Comprehension

Question 1.
“Nobody wanted to be Mends with the boy.” Why?
Answer:
The boy would scold kids, neighbours and even his friends. So, his friends and neighbours ignored him.

Question 2.
Why were the boy’s parents worried about him?
Answer:
The boy’s parents tried to explain his mistake to him in all possible ways. But all their attempts failed.

Question 3.
What did the boy’s father ask him to do when he got angry?
Answer:
He told his son that whenever he lost his temper, he had to hammer a nail into the fence.

Question 4.
Why did the number of nails driven on the board gradually decrease?
Answer:
The boy found hammering the nails very difficult and he controlled his anger.

Question 5.
What is the moral of the story?
Answer:
Let our words be polite and kind. / Unkind words cause lasting damage.

State whether the following statements are true/ false :
1. The boy’s parents were very happy with the boy.
2. The boy was very bad tempered.
3. The boy was playing with the hammer and nail.
4. The boy’s father asked him to pull out one nail every time when he holds his temper all day long.
5. We should treat everyone with love and respect.
Answer:

1. False
2. True
3. False
4. False
5. True

Study Skill

Study the tree diagram and answer the questions.

Questions:
1. What is the tree diagram about?
Answer:
This tree diagram is about language skills.

2. What are the four basic skills in learning a language?
Answer:
Speaking, writing, listening and reading

3. Number of receptive skills are ________.
a) 1
b) 2
c) 3
Answer:
b) 2

4. Editing is one of the sub-skills of ______
a) listening
b) reading
c) writing
Answer:
c) writing

5. Reading is one of the skills.
a) productive
b) receptive
c) active
Answer:
b) receptive

Fun Time

Add a letter to the given word to make it a new one. You can use the clue given in brackets. The first one is done for you.

1. ink pink (a colour)
2. old : g o l d (a metal)
3. word : s w o r d (a weapon)
4. pine : s p i n e (backbone)
5. wig : t w i g (part of a plant)
6. ask : t a s k (the work assigned)

Check Point

Nails in the Fence Summary

Once there was a boy who had a bad temper. His father was worried. One day he gave his son a bag full of nails and asked to hammer a nail into the back of the fence every time he lost his temper. The boy agreed.

The first day he had driven 30 nails into the fence. Over the next few weeks, as he learned to control his anger, the number of nails hammered daily gradually dwindled down. He discovered it was easier to hold his temper than to drive those nails into the fence.

Finally the day came when the boy didn’t lose his temper at all. He told his father about it and the father suggested that the boy should gradually remove some of the nails every day. The days passed and the young boy was finally able to remove almost all the nails except a few. He approached his father and told him that all the nails were gone.

Then the father said, “You have done well, my son, but look at the holes in the fence. The fence will never be the same. You removed almost the nails but the holes they left could not be removed. The nails you could not remove are like the permanant scars on people’s minds. They will remain there forever.”

The boy then understood the power of words. He realised his mistake and prom-ised his parents that he would be kind and polite.

SCERT AP 9th Class Physics Study Material Pdf Download 1st Lesson చలనం Textbook Questions and Answers.

AP State Syllabus 9th Class Physical Science 1st Lesson Questions and Answers చలనం

9th Class Physical Science 1st Lesson చలనం Textbook Questions and Answers

అభ్యసనాన్ని మెరుగుపరుచుకోండి

ప్రశ్న 1.
“ఆమె స్థిరవడితో నిర్దిష్ట దిశలో పరిగెడుతుంది.” ఈ వాక్యాన్ని చలనానికి సంబంధించిన భావనల ఆధారంగా తక్కువ పదాలలో రాయండి. (AS 1)
జవాబు:
“ఆమె స్థిర వేగంతో చలిస్తుంది”.

కారణం :
నిర్దిష్ట దిశలో స్థిరవడిని స్థిర వేగం అంటారు.

ప్రశ్న 2.
పటంలో A, B అనే రెండు కార్ల చలనాన్ని చూపే s – t (స్లు ఇవ్వడం జరిగింది. ఏ కారు వడి ఎక్కువ? ఎందుకు? (AS 1)

జవాబు:
A – కారు ఎక్కువ వడి కలిగి ఉంటుంది.

కారణం :
A, B ల నుండి X, Y అక్షాలకు లంబాలను గీచినపుడు, కారు తక్కువ సమయం (t₁)లో ఎక్కువ దూరం (s₁) ప్రయాణించినట్లుగా తెలుస్తుంది.
(లేదా)
OA మరియు OBరేఖల వాలులు ఏదైనా బిందువు వద్ద కనుగొనండి. OA వాలు ఎక్కువ రెట్లుగా గమనిస్తాము. కావున ఈ వడి ఎక్కువ.

ప్రశ్న 3.
వది, వేగాల మధ్య భేదమేమి? వివరించండి. (AS 1)
జవాబు:

ప్రశ్న 4.
స్థిర త్వరణం అనగానేమి? (AS 1)
జవాబు:

1. వేగంలో మార్పురేటును త్వరణం అంటారు.
2. త్వరణం అనేది ఒక వస్తువు యొక్క వేగంలో మార్పు ఎంత త్వరగా జరుగుతుందో తెలియజేస్తుంది.
3. నిర్దిష్ట కాలవ్యవధులలో ఒక వస్తువు వేగంలో మార్పులు సమానంగా ఉంటే, ఆ వస్తువు త్వరణాన్ని సమత్వరణం అంటారు.
4. ఉదాహరణకు మనం ఒక కారు నడుపుతున్నామనుకుందాం. ఆ కారు వేగాన్ని ఒక సెకనులో 30 కి.మీ/గం. నుండి 35 కి.మీ/గం||కు, తర్వాత సెకనులో 35 కి.మీ/ గం|| నుండి 40 కి.మీ | గం||కు, అదే క్రమంలో ప్రతి సెకనుకు దాని వేగాన్ని పెంచుతున్నామనుకుందాం. ఈ సందర్భంలో కారు వేగం ప్రతి సెకనుకు 5 కి.మీ/గం. చొప్పున పెరుగుతుంది. దీనినే ‘స్థిరత్వరణం’ అంటారు.

ప్రశ్న 5.
“ఒక కారు 70 కి.మీ./గం|| స్థిరవేగంతో వక్రమార్గంలో చలిస్తుంది.” అని మీ స్నేహితుడు మీతో అంటే అతను చెప్పిన దానిని మీరెలా సరిచేస్తారు? (AS 1)
జవాబు:
“ఒక కారు 70 కి.మీ./ గం. స్థిరవడితో వక్రమార్గంలో చలిస్తుంది.”

కారణం :
వక్రమార్గంలో వడి స్థిరంగా వుంటుంది. కాని వేగం మారుతూ ఉంటుంది.

ప్రశ్న 6.
ఒక కణం స్థిర వేగంతో చలిస్తుంది. ఏదేని నిర్ణీత కాలవ్యవధిలో దాని సరాసరి వేగం, తక్షణ వేగంతో సమానంగా ఉంటుందా? లేదా? వివరించండి. (AS 2, AS 1)
జవాబు:
ఇక్కడ వేగం స్థిరంగా వుంది. కావున ఏదేని నిర్ణీత కాలవ్యవధిలో దాని సరాసరి వేగం తక్షణ వేగంతో సమానంగా ఉంటుంది.
ఉదా :
ఒక తిన్నని రోడ్డుపై ఒక కారు 10 మీ/సె ఫిరవేగంతో చలిస్తున్నదనుకొనుము.
1 సె||లో కారు ప్రయాణించిన దూరం (AB) = 10 మీ.

అదే విధంగా 2 సె॥లో కారు ప్రయాణించిన దూరం (AC) = 10 × 2 = 20 మీ.
∴ A నుండి C కు గల సరాసరి వేగం = \(\frac{20}{2}\) = 10 మీ/సె.
∴ A లేదా B లేదా C లేదా ఏదేని బిందువు వద్ద దాని తక్షణ వడి = 10 మీ/సె.

ప్రశ్న 7.
ఒక వస్తువు త్వరణం స్థిరంగా ఉన్నప్పుడు దాని వేగందిశ పూర్తిగా వ్యతిరేక దిశలోనికి మారగలదా? ఒక ఉదాహరణతో వివరించండి. అలా మారడం వీలుకాదనుకుంటే ఎందుకు కాదో వివరించండి. (AS 2, AS 1)
జవాబు:
నిట్టనిలువుగా పైకి విసిరిన వస్తువు విషయంలో ఇది నిజమగును.
ఉదా: ఒక వస్తువును నిట్టనిలువుగా పైకి విసిరామనుకోండి. అది పైకి పోవునపుడు దాని వేగం పై దిశలో వుంటుంది. కాని అదే వస్తువు క్రిందికి పడేటప్పుడు దాని వేగ దిశ క్రిందికి ఉంటుంది. ఈ రెండు సందర్భాలలోను త్వరణం (సంఖ్యాత్మకంగా) సమానంగా ఉంటుంది. కాని దిశ మాత్రం వ్యతిరేకంగా ఉంటుంది.

ప్రశ్న 8.
పటంలో చూపిన విధంగా ఒక కణం వక్రమార్గంలో చలిస్తుంది. A నుండి B కి, స్థానభ్రంశ సదిశను గీయండి. (AS 5)

జవాబు:

ప్రశ్న 9.
ఒక వస్తువు వడి ఏకరీతిగా తగ్గుతూ వుంటే దాని చలనాన్ని తెలిపే దూరం – కాలం గ్రాఫ్ గీయండి. (AS 5)
జవాబు:
బ్రేకులు వేసిన తరువాత ఒక కారు చలనాన్ని గమనించండి. దాని చలనం క్రింది విధంగా వున్నదనుకోండి.

కాలము (t) సెకండ్లలో	దూరము (s) మీటర్లలో
0	20
1	18
2	16
3	14
4	12
5	10

ప్రశ్న 10.
తాబేలు మరియు కుందేలుల పరుగు పందెం కథ మీరు వినే ఉంటారు. తాబేలు ప్రయాణించే వడి కంటే కుందేలు ప్రయాణించే వడి ఎక్కువ. రెండూ ఒకే చోటు నుండి పరుగుపందెం ప్రారంభించాయి. కుందేలు కొంత దూరం ప్రయాణించి చెట్టు కింద కాసేపు విశ్రాంతి తీసుకుంది. కుందేలు నిద్ర లేచి చేరవలసిన గమ్యం వైపు పరిగెత్తింది. కుందేలు గమ్యానికి చేరేసరికి తాబేలు అప్పటికే గమ్యాన్ని చేరింది. ఈ కథను దూరం-కాలం గ్రాస్లో చూపండి. (AS 5)
జవాబు:

1. OX – తాబేలు చలనము.
2. ‘OABC-కుందేలు చలనము.
3. కుందేలు, తాబేలు ‘O’ వద్ద బయలుదేరినాయి.
4. ‘t₁ కాలం తరువాత కుందేలు ‘A’ వద్ద, తాబేలు ‘P’ వద్ద వున్నాయి.
5. తరువాత ‘t₂‘ సమయం వరకు కుందేలు విశ్రాంతి తీసుకుంది.
6. ‘t₂‘ కాలం తరువాత తాబేలు Qవద్ద ఉన్నది కాని కుందేలు స్థానభ్రంశం చెందలేదు.
7. ‘t₃‘ కాలం తరువాత తాబేలు తన గమ్యస్థానమైన Xను చేరుతుంది.
8. కాని ఆ గమ్యాన్ని కుందేలు ‘t₄‘ సమయం తరువాత చేరుకున్నది.

ప్రశ్న 11.
4 సె.లో ఒక చిరుత 100 మీ. దూరం పరిగెడుతుంటే, దాని సరాసరి వడి ఎంత? అదే చిరుత 2 సె.లో 50 మీ.దూరం పరిగెడినచో దాని సరాసరి వడి ఎంత? (AS 1, AS 7)
జవాబు:

ప్రశ్న 12.
రెండు రైళ్లు 30 కి.మీ./గం. వడితో ఒకే ట్రాక్ పై వ్యతిరేక దిశల్లో చలిస్తున్నాయి. ఒక పక్షి ఒక రైలు నుండి రెండవ రైలుకు 60 కి.మీ./గం. వడితో ఎగరగలదు. రెండు రైళ్ల మధ్య 60 కి.మీ. దూరం ఉన్నప్పుడు పక్షి ఎగరటం ప్రారంభించింది. పక్షి రెండవ రైలును తాకి మరల మొదటి రైలు వైపు, మరల మొదటి రైలు నుండి రెండవదాని వైపు, ఆ రెండు రైళ్లు ఢీకొనేంత వరకు ఎగిరింది. పక్షి ఎన్నిసార్లు ప్రదక్షిణాలు చేసింది ? పక్షి ప్రయాణించిన దూరం ఎంత? (AS 1)
జవాబు:
1వ పద్దతి:
ప్రతి రైలు వేగము = 30 కి.మీ / గం||
మొదటి రైలు, రెండవ రైలు కూడా ఒక గంటలో 30 కి.మీ. ప్రయాణించగలవు.
రెండు రైళ్ళ మధ్య దూరము = 60 కి.మీ
కావున రెండు రైళ్ళు ఒక గంటలో ఢీకొంటాయి.
పక్షి ఒక రైలు నుండి రెండవ రైలుకు 60 కి.మీ / గం. వేగంతో చలిసుంది.

∴ రెండు రైళ్ళు ఢీకొనుటకు ముందు పక్షి 60 కి.మీ దూరం ప్రయాణించును.
కాని రెండు రైళ్ళు ఢీకొనక ముందు, ఢీకొన్న తరువాత ఆ పక్షి అనంతమైన ప్రదక్షిణలు చేస్తుంది.

2వ పద్దతి:
రెండు రైళ్ళ సాపేక్ష వేగం = 60 కి.మీ./ గం||
రెండు రైళ్ళు ఢీకొనుటకు పట్టు సమయం = t సె॥ అనుకొనుము.
రెండు రైళ్ళ మధ్యదూరం = 60 కి. మీ.
∴ \(t=\frac{d}{s}=\frac{60}{60}=1\) గం||

పక్షి వేగము = 60 కి.మీ.
1 గం||లో పక్షి ప్రయాణించిన దూరం = 60 కి.మీ.
ఉదాహరణకు పక్షి B నుండి ‘X’ కి.మీ. దూరంలో (A వద్ద) ఉందనుకోండి. అప్పుడు ఆ పక్షి ‘t’ సమయంలో A రైలును ‘C’ వద్ద ఢీ కొట్టును.

ప్రశ్న 13.
ఒక రాయిని భావిలోకి జారవిడిచినప్పుడు అది 2 సెకన్లలో నీటి ఉపరితలాన్ని తాకినది. ఆ రాయి ఎంత వేగంతో ఉపరితలాన్ని తాకినది మరియు పై నుండి నీటి ఉపరితలం ఎంత లోతులో ఉన్నది? (AS 1)
(g = 10m/s², V= U + at, S = Ut + 1/2 at²)
జవాబు:
దత్తాంశం ప్రకారం; t = 2 సె; 1 = (0 మీ./సె [∵ స్వేచ్ఛగా పడుతున్న రాయి); v = ?
లోతు, s = ?; a = g = 10 మీ./సె²
i) v = u + at; v = 0 + 10 × 2 = 20 మీ./సె
ii) s = ut + \(\frac{1}{2}\) at² = 0 + \(\frac{1}{2}\) × 10 × 2² = \(\frac{1}{2}\) × 10 × 4 = 20 మీ.
∴ రాయి ఉపరితలాన్ని తాకిన వేగం = 20 మీ/సె
పై నుండి నీటి ఉపరితలంలోతు = 20 మీ.

ప్రశ్న 14.
ఒక వస్తువు 6 మీ/సె వేగంతో కదులుతూ తరువాత 3 సెకన్లలో 2 మీ/సె² చొప్పున త్వరణం చెందినది. సమయంలో
వస్తువు ఎంత దూరం ప్రయాణించినది ? (S = Ut + 1/2 at²) (AS 1)
జవాబు:
దత్తాంశం ప్రకారం
u = 6 మీ/సె. ; t = 3 సెకనులు; a = 2 మీ./సె²
s = ut + \(\frac{1}{2}\) at² = 6 × 3 + \(\frac{1}{2}\) × 2 × 3² = 18 + 9 = 27 మీ.
∴ 3 సెకనుల సమయంలో వస్తువు ప్రయాణించిన దూరం = 27 మీ.

ప్రశ్న 15.
ఒక కారు 40 మీ/సె వేగంతో ప్రయాణిస్తున్నప్పుడు బ్రేకు వేయగా 8మీ దూరం ప్రయాణించి ఆగినది. కారు త్వరణాన్ని కనుగొనండి. (v² – u² = 2as) (AS 1)
జవాబు:
దత్తాంశం ప్రకారం
u = 40 మీ/సె.; V = 0 (కారు ఆగినది కనుక); S = 8మీ.; a = ?
v² – u² = 2as
0 – 40² = 2 × a × 8

కారుత్వరణం = 100 మీ/సె².
త్వరణానికి ‘-‘ గుర్తు ఉన్నది కనుక కారుత్వరణం ఋణత్వరణం.

ప్రశ్న 16.
ఒక కణం సమత్వరణ చలనంలో ఉంది. ఆ కణం ‘n’ వ సెకనులో పొందిన స్థానభ్రంశానికి సమీకరణాన్ని ఉత్పాదించండి. [S_n = u + a(n – 1/2)] (AS 1)
జవాబు:
సెకనులో వస్తువు పొందిన స్థానభ్రంశం S = ut + \(\frac{1}{2}\) + at² (సమచలన సమీకరణం)
∴ ‘n’ సెకనులలో వస్తువు పొందిన స్థానభ్రంశం S_n(sec) = un + \(\frac{1}{2}\) an² ………….. (1)
∴ (n – 1) సెకనులలో వస్తువు పొందిన స్థానభ్రంశం, S_(n-1)sec = u (n – 1) + \(\frac{1}{2}\) a (n – 1)²………….. (2)
∴ nవ సెకనులో వస్తువు పొందిన స్థానభ్రంశం S_n = S_{(a sec)} – S_{(n – 1)sec}

ప్రశ్న 17.
ఒక కణం ‘O’ బిందువు నుండి బయలుదేరి, స్థిర త్వరణంతో చలిస్తూ ‘O’ బిందువును విడిచి పెట్టింది. 5 సెకన్ల తర్వాత దాని వడి 1.5 మీ./సె. 6వ సెకను చివర అది నిశ్చలస్థితికి వచ్చి మరల వెనుకకు తిరిగి చలిస్తుంది. అది నిశ్చల స్థితికి వచ్చేలోపు ఆ కణం ప్రయాణించిన దూరమెంత ? వెనుదిరిగిన కణం ఎంత వేగంతో ‘O’ బిందువును చేరుతుంది? (AS 1)
జవాబు:
5వ సెకనులో వేగం = 1.5 మీ/సె.

6వ సెకనుకు నిశ్చల స్థితికి వస్తుంది.
∴ 6వ సెకనులో తుదివేగం v = 0 మీ/సె.
6వ సెకనులో త్వరణం v = u + at
0 = 1.5 + a.1
∴ a = -1.5 మీ/సె² (∵ 5వ సెకనులో వేగం, 6వ సెకనులో తొలివేగమవుతుంది. కాలం = 6 – 5 = 1 సె॥)
6 సెకనుల తరువాత, వస్తువు నిశ్చలస్థితికి వస్తుంది.
v = 0, a = – 1.5 మీ/సె², u = ? t = 6 సె.
v = u + at
0 = u + (-1.5) × 6
∴ u = 9 మీ/సె.
నిశ్చలస్థితికి వచ్చేసరికి అనగా 6 సెకనులలో వస్తువు ప్రయాణించిన దూరం
s = ut + \(\frac{1}{2}\) at² = 9 × 6 + \(\frac{1}{2}\) ×- 1.5 × 6²
s = 54 – 27 = 27 మీ.

ఇప్పుడు కణం వెనుకకు మరలుతుంది.
v = 0 మీ/సె, t = 6 సె, a = -1.5 మీ/సె².
v = u + at
v = (0 – 1.5 × 6
v = – 9
∴ తిరుగు ప్రయాణంలో వేగం = -9 మీ/సె.

ప్రశ్న 18.
ఒక కణం స్థిరత్వరణం ‘a’ తో నిశ్చలస్థితి నుండి బయలుదేరి ‘t’ కాలం ప్రయాణించిన తర్వాత దాని త్వరణం దిశ పూర్తిగా వ్యతిరేక దిశలోకి మారింది. కాని దాని త్వరణం పరిమాణంలో ఏ మార్పు లేదు. ఆ కణం తిరిగి బయలుదేరిన బిందువుకు చేరడానికి ఎంత సమయం పడుతుంది? (AS 1)
జవాబు:

ఒక కణం ‘a’ వద్ద బయలుదేరినదనుకొనుము.
దాని తొలివేగం u = 0 మీ/సె
స్థానభ్రంశం = 6 మీ.
త్వరణం = a మీ/సె²
కాలము = t సెకనులు

స్థానభ్రంశం s = ut + \(\frac{1}{2}\) at = ot – \(\frac{1}{2}\)at
s = \(\frac{1}{2}\)at² ……… (1)
తుదివేగం (v) = u + at = v = at ………… (2)
‘t₂‘ కాలం తరువాత దాని దిశను మార్చుకుంటుంది. కాని పరిమాణం సమానంగా ఉంటుంది. అప్పుడు కణం B నుండి Aకి కదులుతుంది.
స్థానభ్రంశం = -s మీ.
త్వరణం = – a మీ/సె²

ప్రశ్న 19.
ఒక రైలు దాని వడిని 20 సెం.మీ/సె. త్వరణంతో పెంచుకోగలదు. అలాగే తన వడిని 100 సెం.మీ/సె. త్వరణంతో తగ్గించుకోగలదు. అయితే ఒకదానితో ఒకటి 27 కి.మీ. దూరంలో ఉన్న రెండు రైల్వేస్టేషన్ల మధ్య ఆ రైలు ప్రయాణించడానికి పట్టే కనీస కాలం ఎంత? (AS 1)
జవాబు:
ఒక రైలు త్వరణం α = 20 సెం.మీ/సె²
దాని రుణ త్వరణం β = 100 సెం.మీ/సె²
రెండు స్టేషన్ల మధ్య దూరం s = 2.7 కి.మీ = 27 × 10⁴ సెం.మీ.
రైలు, రెండు స్టేషన్ల మధ్య ప్రయాణించడానికి పట్టే కనీస కాలం t సె|| అనుకొనుము.

ప్రశ్న 20.
50 మీ. పొడవు గల రైలు 10 మీ/సె. స్థిర వడితో చలిస్తుంది. ఆ రైలు ఒక విద్యుత్ స్తంభాన్ని మరియు 250 మీ. పొడవు గల బ్రిడ్జిని దాటడానికి పట్టే కాలాన్ని లెక్కించండి. (AS 1)
జవాబు:
(i) రైలు పొడవు = 50 మీ.
రైలు వడి V = 10 మీ./సె.
రైలు విద్యుత్ స్తంభాన్ని దాటుటకు అది ప్రయాణించిన దూరము = రైలు పొడవు (s) = 50 మీ.
∴ రైలు విద్యుత్ స్తంభాన్ని దాటుటకు పట్టు కాలము \(\mathrm{t}=\frac{\mathrm{s}}{\mathrm{v}} \Rightarrow \mathrm{t}=\frac{50}{10}=5\) సెకనులు

(ii) బ్రిడ్జి పొడవు = 250 మీ. రైలు బ్రిడ్జిని దాటుటకు ప్రయాణించిన దూరం (s)= రైలు పొడవు + బ్రిడ్జి పొడవు
⇒ s = 50 + 250 = 300 మీ.
రైలు బ్రిడ్జిని దాటుటకు పట్టు కాలము \(\mathrm{t}=\frac{\mathrm{s}}{\mathrm{v}} \Rightarrow \mathrm{t}=\frac{300}{10}=30\) సెకనులు

ప్రశ్న 21.
పటంలో చూపిన విధంగా ఒకే ఎత్తు గల మూడు రకాలైన తలాల నుంది, ఒకే రకమైన మూడు బంతులను జారవిడిచినచో, ఏ బంతి త్వరగా నేలను చేరుతుంది? వివరించండి. (AS 2 AS 1)

జవాబు:
మొదటి కొండపై నుండి జారవిడిచిన బంతి ముందుగా నేలను చేరును.

కారణం:

1. మొదటి కొండపైనున్న బంతి రేఖీయ చలనంలో ఉండును.
2. కావున దాని వడి మరియు వేగము ఒకే పరిమాణం, దిశ కలిగియుండును.
3. రెండవ మరియు మూడవ కొండల పైనున్న బంతులు వక్రమార్గంలో ప్రయాణించును.
4. కావున వీటి వేగ దిశ నిరంతరం మారును.

ప్రశ్న 22.
నిశ్చలస్థితి నుండి బయలుదేరిన ఒక వస్తువు యొక్క వడి ఏకరీతిగా పెరుగుతున్నట్లయితే వస్తువు యొక్క చలనాన్ని చూపే దూరం – కాలం ను గీయండి. (AS 5)
జవాబు:
ఒక కారు క్రింది పట్టికలో చూపిన విధంగా చలిస్తున్నదనుకొనుము.

కాలము (t) సెకండ్లలో	దూరము (s) మీటర్లలో
0	0
1	3
2	6
3	9
4	12
5	15

ప్రశ్న 23.
ఒక కారు తన ప్రయాణ కాలంలో మొదటి సగం కాలం 80 కి.మీ./గం. వడితోను, మిగిలిన సగం కాలం 40 కి.మీ./గం. వడితోనూ ప్రయాణిస్తే, దాని సరాసరి వడి ఎంత?
జవాబు:
మొత్తం ప్రయాణించిన కాలం = xగం|| అనుకొనుము.
మొదటి సగం కాలం (అనగా \(\frac{x}{2}\)గం॥) లో దాని వడి = 80 కి.మీ | గం||
∴ \(\frac{x}{2}\) గం||లలో ప్రయాణించు దూరం = 80 × \(\frac{x}{2}\) = 40 x కి.మీ/గం.
మిగిలిన సగం కాలములో వడి = 40 కి.మీ/గం.
∴ మిగిలిన \(\frac{x}{2}\) గం||లలో ప్రయాణించిన దూరం = 40 × \(\frac{x}{2}\) = 20 x కి.మీ/గం.
∴ మొత్తం ప్రయాణించిన దూరం = 40x + 20x = 60x కి.మీ.
మొత్తం ప్రయాణానికి పట్టిన కాలం = x గం||

ప్రశ్న 24.
ఒక కారు తాను ప్రయాణించిన మొత్తం దూరంలో మొదటి సగం దూరం 50 కి.మీ./గం. వడితోనూ, మిగిలిన సగం దూరం 10 కి.మీ./గం. వడితోనూ ప్రయాణిస్తే, ఆ కారు సరాసరి వడి ఎంత? (AS 1)
జవాబు:
కారు ప్రయాణించిన మొత్తం దూరం = x కి. మీ. అనుకొనుము.

ప్రశ్న 25.
ఒక కణం మొదటి 5 సెకనుల్లో 10మీ. దూరం తర్వాత 3 సెకనులలో 10మీ. దూరం ప్రయాణించింది. ఆ కణం సమత్వరణంతో చలిస్తుందనుకొంటే ఆ కణం తొలివేగాన్ని, త్వరణాన్ని మరియు తదుపరి 2కె.లో ప్రయాణించిన దూరాన్ని కనుగొనండి. (AS1, AS7)
జవాబు:
మొదటి 5 సెకన్లలో ప్రయాణించిన దూరం = 10 మీ.
t₁ = 5 సె||; s₁ = 10 మీ.
s = ut + \(\frac{1}{2}\) at² అని మనకు తెలుసు.
10 = u × 5 + \(\frac{1}{2}\) a . 5²

తరువాతి 2 సె॥లలో వస్తువు ప్రయాణించిన దూరం కనుగొనుటకు ముందు ఈ రెండు సెకనులకు తొలివేగాన్ని కనుగొనాలి. ఇది 8సె|| తరువాత తుదివేగానికి సమానము.

∴ కణం తరువాత 2 సె॥॥లలో 8.33 మీ. దూరం ప్రయాణిస్తుంది.

ప్రశ్న 26.
ఒక కారు నిశ్చలస్థితి నుండి బయలుదేరింది. అది కొంతసేపు స్థిర త్వరణం “α” తో ప్రయాణించి, ఆ తర్వాత స్థిర ఋణత్వరణం “β” తో చలిస్తూ నిశ్చలస్థితికి వచ్చింది. ఆ కారు యొక్క మొత్తం ప్రయాణ కాలం “t” అయితే, ఆ కారు పొందే గరిష్ఠ వేగమెంత? (AS 2, AS7)
జవాబు:
త్వరణం a = α మీ/సె²
తొలివేగం u = 0 మీ/సె²
కాలం = t₁ సె|| అనుకొనుము.
v = u + at సమీకరణం నుండి
⇒ v= 0 + αt₁ ⇒ v = αt₁
∴ \(t_{1}=\frac{v}{\alpha}\)సె
ఋణత్వరణం = – β మీ/సె²
ఇక్కడ ‘α’ త్వరణంతో ప్రయాణించే వస్తువు తుది వేగమే తిరుగు ప్రయాణంలో తొలివేగం ‘u’ అవుతుంది.
∴ u = αt₁ మీ/సె
తుదివేగం v = 0 మీ/సె.
v = u + at సమీకరణం నుండి
0 = αt₁ + (-β)t₂

ప్రశ్న 27.
బస్సుకు 48 మీ. దూరంలో ఒక మనిషి నిలబడి ఉన్నాడు. బస్సు బయలుదేరగానే, ఆ వ్యక్తి 10 మీ./సె. స్థిరవేగంతో బస్సు వైపు పరిగెత్తాడు. బస్సు నిశ్చలస్థితి నుండి 1 మీ./సె.² త్వరణంతో చలిస్తుంది. ఆ వ్యక్తి ఆ బస్సు పట్టుకోగల కనీస సమయాన్ని లెక్కించండి. (AS 1 AS 7)
జవాబు:
బస్సును మనిషి n సెకనులలో పట్టుకోగలడు అనుకుందాం.
బస్సు నిశ్చలస్థితిలో ఉన్నది.
u = 0 మీ/సె ; a = 1 మీ/సె²
ఆ బస్సు n సెకనులలో 8 దూరం ప్రయాణిస్తుందనుకొనుము.

మనిషి బస్సును పట్టుకోవడానికి పట్టు కనీస సమయం = 8 సె॥

9th Class Physical Science 1st Lesson చలనం Textbook InText Questions and Answers

9th Class Physical Science Textbook Page No. 5

ప్రశ్న 1.
ఒక వస్తువు కొంత దూరం ప్రయాణించి తిరిగి బయలుదేరిన చోటుకే చేరుకుంటే దాని స్థానభ్రంశమెంత? ఈ సందర్భానికి నిజ జీవితంలోని ఒక ఉదాహరణ ఇవ్వండి.
జవాబు:
ఒక వస్తువు కొంత దూరం ప్రయాణించి తిరిగి బయలుదేరిన చోటుకి చేరుకుంటే దాని స్థానభ్రంశం ‘సున్న’.
ఉదా : ఒక వ్యక్తి తన ఇంటి నుండి బయలుదేరి మార్కెట్టుకి వెళ్ళి తిరిగి ఇంటికి చేరుకున్నప్పుడు అతని స్థానభ్రంశం ‘సున్న’ అవుతుంది.

ప్రశ్న 2.
దూరం, స్థానభ్రంశముల పరిమాణములు ఎప్పుడు సమానమవుతాయి?
జవాబు:
ఒక వస్తువు ఒక సరళరేఖ వెంబడి ఒకే దిశలో రెండు బిందువుల మధ్య చలించినపుడు ఆ వస్తువు దూరం, స్థానభ్రంశ పరిమాణములు సమానమవుతాయి.

9th Class Physical Science Textbook Page No. 6

ప్రశ్న 3.
ఒక కారు 5 గంటల్లో 200 కి.మీ. దూరం ప్రయాణించిన, దాని సరాసరి వడి ఎంత?
జవాబు:
కారు ప్రయాణించిన మొత్తం దూరం = 200 కి.మీ
ప్రయాణించిన కాలం = 5 గం||లు

ప్రశ్న 4.
ఏ సందర్భంలో సరాసరి వేగం శూన్యమవుతుంది?
జవాబు:
ఒక వస్తువు యొక్క స్థానభ్రంశం శూన్యమయినపుడు దాని సరాసరి వేగం శూన్యమవుతుంది.

ప్రశ్న 5.
ఒక వ్యక్తి కారులో 25 గంటలు ప్రయాణించాడు. కారు ఓడోమీటర్లో తొలి, తుది రీడింగులు వరుసగా 4849 మరియు 5549 గా గుర్తించాడు. అయితే పూర్తి ప్రయాణంలో అతని సరాసరి వడి ఎంత?
జవాబు:
కారు ప్రయాణించిన దూరము = 5549 – 1849 = 700 కి.మీ.
ప్రయాణించిన కాలము = 25 గం||లు

9th Class Physical Science Textbook Page No. 9

ప్రశ్న 6.
a) రోడ్డుపై అతి వేగంతో ప్రయాణించే వాహనదారులకు పోలీసులు జరిమానా విధించడం మీరు గమనించి ఉంటారు. ఈ జరిమానా వారి వడి ఆధారంగా విధిస్తారా? లేదా సరాసరి వడి ఆధారంగా విధిస్తారా? వివరించండి.
జవాబు:
తక్షణ వడి ఆధారంగా జరిమానా విధిస్తారు.

b) ఒక విమానం ఉత్తర దిశలో 300 కి.మీ/గం. వేగంతోనూ, మరొక విమానం దక్షిణ దిశలో 300 కి.మీ/గం. వేగంతోనూ ప్రయాణిస్తున్నవి. వాటి వడులు సమానమా? లేదా వేగాలు సమానమా? వివరించండి.
జవాబు:

1. వాటి వడులు సమానము.
2. వేగము పరిమాణములో సమానము కాని దిశ మాత్రము వ్యతిరేకము.

c) చలనంలో గల ఒక కారులోని స్పీడోమీటరు స్థిర విలువను చూపుతుంది. దీని ఆధారంగా కారు స్థిర వేగంతో చలిస్తుందని చెప్పగలమా? వివరించండి.
జవాబు:

1. కారులోని స్పీడోమీటరు ముల్లు, కారు వడి యొక్క స్వల్ప మార్పులకు కూడా దాని స్థానాన్ని మార్చుకుంటుంది.
2. కాని ఈ సందర్భంలో స్పీడోమీటరు స్థిర విలువను చూపిస్తుంది. కావున కారు స్థిర వేగంతో చలిస్తుందని చెప్పవచ్చు.

9th Class Physical Science Textbook Page No. 11

ప్రశ్న 7.
ఒక చీమ బంతి ఉపరితలంపై కదులుతుంది. దాని వేగం స్థిరమా? అస్థిరమా? వివరించండి.
జవాబు:
వేగం దిశ అస్థిరము.

వివరణ:
చీమ, బంతి ఉపరితలంపై కదులుతున్నది. కావున అది వృత్తాకార మార్గంలో చలించాలి. వృత్తాకార మార్గంలో వేగ దిశ నిరంతరం మారుతుంది. కావున వేగదిశ అస్థిరము.

ప్రశ్న 8.
వడి మారుతూ చలనదిశలో మార్పులేని చలనాన్ని సూచించే సందర్భాలకు ఒక ఉదాహరణ ఇవ్వండి.
జవాబు:
రోడ్డుపై ప్రయాణించే బస్సు

9th Class Physical Science Textbook Page No. 13

ప్రశ్న 9.
300 కి.మీ/గం. స్థిరవేగంతో చలించే కారు త్వరణమెంత?
జవాబు:
వేగం = 300 కి.మీ/ గం|| = \(300 \times \frac{5}{18}=\frac{500}{6}=83.33\) మీ/సె॥
వేగము స్థిరంగా ఉన్నది. కావున త్వరణం కూడా స్థిరము.
∴ త్వరణము = 83.33 మీ/సె²

ప్రశ్న 10.
ఒక విమానం వేగం 1000 కి.మీ./గం. నుండి 1005 కి.మీ/గం.కు చేరటానికి 10 సెకనులు పట్టింది. స్కేటింగ్ చేసే వ్యక్తి వేగం శూన్యం నుండి 5 కి.మీ/గం. చేరటానికి 1 సెకను పట్టింది. వీరిలో ఎవరి త్వరణం ఎక్కువ?
జవాబు:
విమానం :
∴ స్కేటింగ్ చేసే వ్యక్తి యొక్క త్వరణం ఎక్కువ.

ప్రశ్న 11.
ఒక వాహన వేగం 100 కి.మీ/గం. నుండి నిశ్చల స్థితికి రావటానికి 10 సెకనులు పట్టిన ఆ వాహన త్వరణం ఎంత?
జవాబు:

ప్రశ్న 12.
“స్థానంలో మార్పు ఎంత త్వరితగతిన వస్తుందో తెలిపే భావనే త్వరణం” అని మీ స్నేహితుడు అన్నాడు. మీ స్నేహితుడిని మీరు ఏ విధంగా సరి చేస్తారు?
జవాబు:
“నిర్ణీత దిశలో స్థానంలో మార్పు ఎంత త్వరితగతిన వస్తుందో తెలిపే భావనే త్వరణం”.

9th Class Physical Science Textbook Page No. 1

ప్రశ్న 13.
భూమి చలనంలో ఉన్నప్పటికీ, ఆ చలనాన్ని మనం ఎందుకు గుర్తించలేకపోతున్నాము?
జవాబు:

1. భూమి చలనంలో వున్నది.
2. భూమి మీద ఉన్న మనం కూడా భూమి వేగానికి సమానమైన వేగంతో చలిస్తున్నాము. అనగా భూమికి, మనకు సాపేక్ష చలనం ఉన్నది.
3. కావున భూమి చలనమును మనం గుర్తించలేకపోతున్నాము.

ప్రశ్న 14.
మీ తరగతి గది గోడలు చలనంలో ఉన్నాయా? లేదా? ఎందుకు?
జవాబు:
పరిశీలకుని దృష్టిలో గోడలు స్థిరంగా వున్నాయి.
చలనంలో ఉన్న భూమి దృష్ట్యా చూసినపుడు గోడలు కూడా చలనంలో వున్నాయని చెప్పవచ్చు.

ప్రశ్న 15.
నిశ్చలస్థితిలో ఉన్న రైలులో మీరు కూర్చుని ఉన్నప్పుడు అది కదులుతున్న అనుభూతిని ఎప్పుడైనా పొందారా? ఎందుకు?
జవాబు:
ఒక నిశ్చలస్థితిలోనున్న రైలులో కూర్చుని ఉన్నప్పుడు, అవతలి ట్రాక్ పైనున్న రైలు కదలికలోకి వచ్చినప్పుడు ఇటువంటి అనుభూతి కలుగుతుంది.

9th Class Physical Science Textbook Page No. 2

ప్రశ్న 16.
ఈ మార్పులు ఎందుకు వస్తాయి?
జవాబు:
భూమి గోళాకారంగా వుందని మనకు తెలుసు. అందువల్ల భూ ఉపరితలంపై గీసిన లంబదిశ భూమి మీద అది గీసిన స్థలంపై ఆధారపడి వుంటుంది. కాబట్టి భూ ఉపరితలంపై ఏ స్థానానికి ఆధారం చేసుకొని దిశను చెబుతున్నామో తెలియనంత వరకు పైకి, క్రిందకి అనే దిశలకు అర్థం లేదు.

ప్రశ్న 17.
ఈ పదాలు సాపేక్షమైనవా? కావా?
జవాబు:
కుడి, ఎడమ; పైకి, కిందకు; పొడవు, పొట్టి అనే పదాలు పరిశీలకుని పరంగా సాపేక్షమైనవి.

9th Class Physical Science Textbook Page No. 4

ప్రశ్న 18.
ప్రయాణికుడు ఏ సమాధానం ఇస్తాడో మీకు తెలుసా?
జవాబు:
రోడ్డుపై నిలుచున్న పరిశీలకుడి పరంగా కారు చలనంలో వుంటుంది. కాని కారులో ఉన్న ప్రయాణికుడి పరంగా చూస్తే కారు నిశ్చలస్థితిలో వుంటుంది. వస్తు చలనం, పరిశీలకుడిపై ఆధారపడి వుంటుంది. కాబట్టి ‘చలనం’ అనేది పరిశీలకుడు, చలించే వస్తువుల ఉమ్మడి ధర్మం.

ప్రశ్న 19.
చలనాన్ని మనం ఏవిధంగా అవగాహన చేసుకుంటాం?
జవాబు:
పరిశీలకుడి పరంగా ఒక వస్తుస్థానం కాలంతోపాటు నిరంతరం మారుతూంటే ఆ వస్తువు చలనంలో వుంది అంటాము.

9th Class Physical Science Textbook Page No. 7

ప్రశ్న 20.
ఒక నిర్దిష్ట సమయం దగ్గర కారు వడి ఎంత ఉంటుందో మనం తెలుసుకోగలమా?
జవాబు:
కారు ప్రయాణిస్తున్నప్పుడు ఏ సమయంలోనైనా దాని వడిని మనం స్పీడోమీటరు చూసి నిర్ణయించవచ్చు.

ప్రశ్న 21.
‘t₃‘ సమయం వద్ద కారు వడి (తక్షణ వడి) ఎంత?
జవాబు:

ఏదైనా ఇచ్చిన సమయం వద్ద గ్రావాలు, ఆ సమయంలో కారు వడిని తెలుపుతుంది. గ్రాఫ్ పై ఏదైనా ఒక బిందువు వద్ద ఆ గ్రాఫ్ యొక్క వాలును ఆ బిందువు వద్ద గీసిన స్పర్శరేఖతో తెలుసుకోవచ్చు. ఈ వాలు, ఆ సమయంలో ఆ కారు యొక్క వడిని తెలుపుతుంది.

9th Class Physical Science Textbook Page No. 8

ప్రశ్న 22.
దానికి కట్టిన వస్తువు ఏ దిశలో చలిస్తుంది?
జవాబు:
వృత్తాకార మార్గంలో చలిస్తున్న వస్తువు, ఆ వస్తువును వదిలిన బిందువు వద్ద గీసిన స్పర్శరేఖ దిశలో చలిస్తుంది.

ప్రశ్న 23.
ఏ రకమైన చలనాన్ని సమచలనం అంటారు? ఎందుకు?
జవాబు:
ఒక వస్తువు స్థిరవేగంతో చలిస్తూ వుంటే ఆ చలనాన్ని ‘సమచలనం’ అంటారు.

9th Class Physical Science Textbook Page No. 9

ప్రశ్న 24.
మీరు గీసిన గ్రాఫ్ ఏ ఆకారంలో ఉంది?

కాలము (t) సెకండ్లలో	దూరము (s) మీటర్లలో
0	0
1	4
2	8
3	12
4	16
–	–

జవాబు:
సమచలనంలో వున్న వస్తువు చలనానికి గీసిన గ్రాఫు ఒక సరళరేఖను సూచిస్తుంది.

9th Class Physical Science Textbook Page No. 10

ప్రశ్న 25.
మీరు గీసిన గ్రాఫ్ ఏ ఆకారంలో ఉంది?
జవాబు:

అసమ చలనంలో ఉన్న వస్తువు యొక్క చలనానికి గీసిన గ్రాఫు ఒక వక్ర రేఖ.

ప్రశ్న 26.
ఆ గ్రాఫ్ సరళరేఖ రూపంలో ఉందా? లేదా మరేదైనా రేఖ లాగా ఉందా? ఎందుకు?
జవాబు:
అసమచలనానికి గీసిన గ్రాఫ్ ఒక సరళరేఖ కాదు. ఎందుకనగా దాని వడి నిరంతరం, అసమంగా మారుతూ ఉంది.

9th Class Physical Science Textbook Page No. 11

ప్రశ్న 27.
వడి స్థిరంగా ఉంది, వేగం నిరంతరంగా మారే సందర్భాలకు కొన్ని ఉదాహరణలివ్వగలరా?
జవాబు:
సమవృత్తాకారచలనంలోనున్న వస్తువుల వడి స్థిరంగా ఉంటుంది. కాని వేగం నిరంతరం మారుతూ ఉంటుంది.
ఉదా: భూభ్రమణం, భూమి చుట్టూ చంద్రుని చలనం మొ||వి.

ప్రశ్న 28.
ఈ చలనంలో రాయి వడి స్థిరమా? ఎందుకు?
జవాబు:
రాయి వడి నిరంతరం మారుతూ ఉంటుంది. కావున అది అసమ చలనం.

ప్రశ్న 29.
రాయి చలనదిశ స్థిరంగా ఉంటుందా?
జవాబు:
రాయి చలనదిశ నిరంతరం మారుతూ ఉంటుంది.

ప్రశ్న 30.
వడి, చలన దిశలు రెండూ నిరంతరం మారే చలనాలకు కొన్ని ఉదాహరణలివ్వండి.
జవాబు:
రాకెట్ చలనము, క్షితిజ సమాంతరంగా విసిరిన వస్తువు, కాలితో తన్నిన ఫుట్ బాల్, బౌలర్చే విసరబడిన క్రికెట్ బంతి మొదలగునవి.

9th Class Physical Science Textbook Page No. 12

ప్రశ్న 31.
త్వరణం అనగానేమి? ఒక వస్తువు త్వరణంలో ఉందని ఎలా తెలుసుకోగలవు?
జవాబు:

1. త్వరణం అనేది ఒక వస్తువు యొక్క వేగంలో మార్పు ఎంత త్వరగా జరుగుతుందో తెలియజేస్తుంది.
2. ఇది వేగంలోని మార్పు రేటుకి సమానము.
3. మనం బస్సు లేదా కారులో ప్రయాణించేటప్పుడు బస్సు డ్రైవరు యాక్సలరేటర్‌ను నొక్కితే మనం వెనకకు పడతాం. మనం పొందిన త్వరణం వలన మనం కూర్చొన్న సీట్లను శరీరం గట్టిగా వెనుకకు నొక్కుతుంది. ఈ విధంగా త్వరణం మన అనుభవంలోకి వస్తుంది.

ప్రశ్న 32.
వస్తువు వడి ఏ బిందువు వద్ద గరిష్ఠంగా వుంది?
జవాబు:
‘B’ వద్ద వస్తువు వడి గరిష్ఠము.

ప్రశ్న 33.
వస్తువుకు త్వరణం ఉన్నదా? లేదా?
జవాబు:
చలనంలోనున్న ఏ వస్తువుకైనా త్వరణం ఉంటుంది.

ఉదాహరణ సమస్యలు

9th Class Physical Science Textbook Page No. 9

ప్రశ్న 1.
‘h’ఎత్తు గల మనిషి సరళరేఖా మార్గంలో ‘v’ వడితో ‘H’ఎత్తు గల వీధిదీపం కింది నుండి ప్రయాణిస్తున్నాడు. వీధిదీపం నుండి వచ్చే కాంతి ఆ మనిషిపై పడి అతని నీడను ఏర్పరచింది. అతను కదులుతున్నప్పుడు నీదకూడా అతనితో పాటు కదులుతుంది. ఆ మనిషి నీడ యొక్క చివరిభాగంలో గల తల ఎంత వడితో కదులుతుందో కనుక్కోండి.
సాధన:
ఇటువంటి సమస్యను సాధించాలంటే మనిషి, అతని నీడ యొక్క చివరి భాగాల చలనాలను పోల్చాలి. ఇవి రెండూ ఒక మూల బిందువు ‘0’ నుండి చలించడం ప్రారంభించాయనుకొందాం. ఇది పటంలో చూపబడింది. “OD” మనిషి ఎత్తును సూచిస్తుంది. అలాగే OA దీపస్తంభం ఎత్తును (H) సూచిస్తుంది.

‘t’ కాలంలో మనిషి, అతడి నీడ యొక్క చివర భాగంలో గల తల ప్రయాణించిన దూరాలు ‘S’ మరియు ‘S’లు అనుకుందాం.

ఈ చలనం వల్ల పటంలో చూపినట్లు ∆ABD, ∆ACO అనే రెండు సరూప త్రిభుజాలు ఏర్పడతాయి.

S/t అనేది మనిషి నీడ యొక్క చివర భాగంలో తల వడిని తెల్పుతుంది. దీనిని ‘V’ తో సూచిస్తే, పై సమీకరణం నుండి మనం నీడ, యొక్క చివర భాగంలో తల వడి

9th Class Physical Science Textbook Page No. 12

ప్రశ్న 2.
400 మీ దూరంలో గల రెడ్ సిగ్నల్ లైటును చూసి 54 కి.మీ./గం. వేగంతో ప్రయాణించే రైలు ఇంజను బ్రేకులు వేశారు. బ్రేకులు కలుగజేసిన త్వరణం a = 0.3 మీ/సె అయితే 1 నిముషం తర్వాత రైలు ఇంజన్ సిగ్నల్ స్తంభానికి ఎంత దూరంలో ఉంటుంది?
సాధన:
రెడ్ సిగ్నల్ ను చూసినపుడు బ్రేకులు వేస్తే రైలు ఇంజన్ రుణత్వరణంతో చలిస్తుంది. ‘I’ కాలం తర్వాత ఆగిపోయిందనుకుందాం.
తొలివేగం 4 = 54 కి.మీ/గం. = 54 × 5/18 = 15 మీ/సె.
తుదివేగం V = 0 (ఇచ్చిన సందర్భానికి)
a = – 0.3 మీ/సె². (ఇంజన్ ఋణత్వరణంతో చలిస్తుంది.)

1 నిముషం తర్వాత రైలు ఇంజన్, సిగ్నల్ స్తంభానికి మధ్య దూరం I = L – S = 400 – 375 = 25 మీ.

ప్రశ్న 3.
ఒక వస్తువు సమత్వరణంతో సరళరేఖా మార్గంలో ప్రయాణిస్తుంది. ఈ సరళరేఖా మార్గంపై గల రెండు బిందువుల వద్ద వస్తు వేగాలు వరుసగా u, v అయిన ఆ రెండు బిందువులకు మధ్య బిందువు వద్ద వస్తువు వేగం ఎంత?
సాధన:
వస్తువు సమత్వరణాన్ని ‘a’ అనుకుందాం.
ఇచ్చిన బిందువుల మధ్య దూరం ‘s’ అనుకుందాం.
v² – u² = 2as …………. (1)

ఈ రెండు బిందువులకు మధ్యబిందువు వద్ద వస్తువు వేగం v₀ అనుకుందాం. (ఆ బిందువును ‘M’ గా పటంలో చూపడం జరిగింది.) అప్పుడు v²₀ – u² = 2as/2
సమీకరణం (1) లోని 2as విలువను పై సమీకరణంలో ప్రతిక్షేపించగా

9th Class Physical Science Textbook Page No. 16

ప్రశ్న 4.
నిశ్చలస్థితి నుండి బయలుదేరిన ఒక కారు సమత్వరణం ‘a’ తో ‘t’ కాలం పాటు ప్రయాణించింది. కారు సరళరేఖా మార్గంలో ప్రయాణించినట్లయితే ‘t’ కాలంలో అది పొందే సరాసరి వడి ఎంత?
సాధన:
కారు నిశ్చలస్థితి నుండి ప్రారంభమైంది కాబట్టి దాని తొలి వేగం u = 0
‘t’ కాలంలో కారు ప్రయాణించిన దూరం

ప్రశ్న 5.
ఒక కణం 9 మీ./సె. వేగంతో తూర్పు దిశలో ప్రయాణిస్తుంది. అది పడమర దిశలో 2మీ./సి². స్థిరత్వరణాన్ని కలిగి ఉంటే దాని ప్రయాణంలో 5వ సెకనులో కణం ప్రయాణించిన దూరం ఎంత?
సాధన:

తొలి వేగం U : + 9 మీ./సె.
త్వరణం a = -2 మీ./సె.²

ఈ సమస్యలో త్వరణం, వేగ దిశలు పరస్పరం వ్యతిరేకంగా ఉన్నాయి. కాబట్టి ఎంత సమయంలో ఆ కణం నిశ్చలస్థితికి వస్తుందో ముందుగా నిర్ణయించాలి. ఆ కాలాన్ని ‘t’ అనుకుందాం.
v = u + at నుండి
0 = 9 – 2t ⇒ t = 4.5 సె.
4.5 సె. నుండి 5 సె. వరకు కణం త్వరణదిశలో చలిస్తుంది. కనుక \(\frac{1}{2}\) సెకనులో అది కదిలిన దూరాన్ని లెక్కిద్దాం.
ఈ సందర్భంలో t = 4.5 సె. వద్ద 1 = 0.
\(\frac{1}{2}\) సె.లో ప్రయాణించిన మొత్తం దూరం,

5వ సెకనులో ప్రయాణించిన మొత్తం దూరం s₀ అనుకుంటే అది 2s కు సమానం అవుతుంది.
s₀ = 2s = 2 (1/4) = 1/2 మీ.

పరికరాల జాబితా

తాడు, రాయి, ఎలక్ట్రికల్ కేసింగ్, స్టీలు పళ్లెం, గాజు గోళీలు, డిజిటల్ వాచ్

9th Class Physical Science 1st Lesson చలనం Textbook Activities (కృత్యములు)

కృత్యం – 1

ప్రయాణించే మార్గాన్ని గీయడం, దూరం – స్థానభ్రంశాల మధ్య తేడాను గమనించడం :
1. దూరం, స్థానభ్రంశాల మధ్య తేడాను గుర్తించడానికి ఒక కృత్యమును తెలిపి, గ్రాఫును గీయుము.
జవాబు:

1. ఒక బంతిని తీసుకొని క్షితిజ తలానికి కొంతకోణం చేసే విధంగా విసరండి.
2. బంతి ప్రయాణించిన మార్గాన్ని గమనించి తెల్లకాగితములపై ఆ మార్గాన్ని గీయండి.
3. ఈ పటం నిర్ణీతకాలంలో బంతి గాలిలో ప్రయాణించిన దూరాన్ని తెలుపుతుంది.
4. ASB వక్రరేఖ పొడవు బంతి ప్రయాణించిన దూరాన్ని తెలుపుతుంది.
5. సరళరేఖ \(\overrightarrow{\mathrm{AB}}\) పొడవు బంతి స్థానభ్రంశాన్ని తెలుపుతుంది.

స్థానభ్రంశం :
నిర్దిష్ట దిశలో వస్తువు కదిలిన కనిష్ఠ దూరాన్ని . స్థానభ్రంశమని అంటారు. దీనిని సదిశతో సూచిస్తారు.

దూరం :
నిర్ణీత కాలంలో వస్తువు కదిలిన మార్గం మొత్తం పొడవును దూరము అంటారు.

కృత్యం – 2

స్థానభ్రంశ సదిశలను గీయడం : 2. కింది సందర్భాలలో A నుండి B కి స్థానభ్రంశ సదిశలను గీయుము.

జవాబు:

కృత్యం – 3

వస్తువు చలన దిశను పరిశీలించుట :
3. వృత్తాకార మార్గంలో చలించే ఒక వస్తువు వేగదిశ, ఆ వృత్తానికి ఏదైనా బిందువు వద్ద గీసిన స్పర్శరేఖ దిశలో ఉంటుందని చూపండి.
జవాబు:

1. ఒక తాడు చివర ఒక రాయి లేదా ఏదైనా వస్తువును కట్టి, తాడు రెండవ చివరను పట్టుకొని క్షితిజ సమాంతర తలంలో గుండ్రంగా తిప్పండి.
2. అలా తిప్పుతూ తాడును వదిలి పెట్టండి.
3. రాయిని మరలా అదే మాదిరిగా తిప్పుతూ వృత్తంలో వేరువేరు బిందువుల వద్ద నుండి తాడును వదలండి.
4. తాడును విడిచి పెట్టే ప్రతి సందర్భంలో రాయి యొక్క చలన దిశను గమనించండి.
5. వృత్తాకార మార్గంలో మీరు వదిలిన బిందువు వద్ద గీసిన స్పర్శరేఖ దిశలో ఆ వస్తువు చలించడం మీరు గమనిస్తారు.
6. కావున వృత్తాకార మార్గంలో చలించే వస్తువు వేగదిశ, ఆ వృత్తానికి ఏదైనా బిందువు వద్ద గీసిన స్పర్శరేఖ దిశలో ఉంటుంది.

కృత్యం – 4

సమచలనాన్ని అవగాహన చేసుకోవడం :

4. సమచలనాన్ని ఒక కృత్యం ద్వారా వివరించండి.
జవాబు:
1. ఒక వ్యక్తి సైకిల్ పై రోడ్డుమీద సరళరేఖా మార్గంలో ప్రయాణిస్తున్నాడనుకుందాం.
2. అతడు వివిధ సమయాల్లో ప్రయాణించిన దూరాలు క్రింది పట్టికలో ఇవ్వబడినవి.

కాలము (t) సెకండ్లలో	దూరము (s) మీటర్లలో
0	0
1	4
2	8
3	12
4	16

3. పై విలువలకు దూరం – కాలం గ్రాఫ్ గీయండి. అది క్రింది విధంగా ఉండెను.

4. సరళరేఖ రూపంలో గల గ్రాఫ్ ను పరిశీలిస్తే సైకిల్ పై ప్రయాణించే వ్యక్తి సమాన కాలవ్యవధులలో సమాన దూరాలు ప్రయాణించాడని తెలుస్తుంది.
5. అదే విధంగా గ్రాఫ్ నుండి, అతని సరాసరి వడి తక్షణ వడికి సమానమని తెలుస్తుంది.
6. సైకిల్ పై వెళ్ళే వ్యక్తి చలన దిశ స్థిరమని మనం భావిస్తే అతని వేగం స్థిరమని చెప్పవచ్చు.
7. ఒక వస్తువు స్థిరవేగంతో చలిస్తూవుంటే ఆ చలనాన్ని ‘సమచలనం’ అంటారు.

కృత్యం – 5

వాలు తలంపై బంతి చలనాన్ని గమనించుట :

5. వడి మారినప్పటికి చలన దిశ స్థిరంగా వుంటుందని నిరూపించే ఒక సందర్భాన్ని వివరించండి.
జవాబు:

1. పటంలో చూపిన విధంగా వాలు తలాన్ని ఏర్పాటు చేయండి.
2. ఒక బంతిని తీసుకొని వాలుతలం పై చివర నుండి వదిలివేయండి.
3. పటంలో వివిధ సమయాలవద్ద బంతి స్థానాలను చూపడం జరిగింది.
4. బంతి గమనాన్ని జాగ్రత్తగా పరిశీలిస్తే, వాలు తలంపై క్రిందికి జారేబంతి వడి క్రమంగా పెరుగుతుందని, బంతి చలన దిశ స్థిరంగా ఉందని మనం గమనించ గలం.
5. ఇప్పుడు బంతిని తీసుకొని అది కొంత వడి పొందే టట్లుగా వాలుతలం కింది భాగం నుండి పైకి నెట్టండి.
6. బంతి కొంతభాగం పైకెళ్ళి మరల క్రిందికి రావడం గమనిస్తాము.
7. ఈ సందర్భాలను గమనిస్తే బంతి వడి మారుతుండడాన్ని, దాని చలన దిశ స్థిరంగా వుండడాన్ని గమనించవచ్చు.

కృత్యం – 6

సమవృత్తాకార చలనాన్ని పరిశీలించుట :

6. “వది స్థిరంగా వుండి, వేగదిశ మారే” సందర్భాన్ని వివరించండి. (లేదా) సమవృత్తాకార చలనాన్ని వివరించండి.
జవాబు:

1. ఒక చిన్న రాయిని తాడుకి కట్టి దీక్షితిజ సమాంతర తలంలో తిప్పండి.
2. పటంలో చూపినట్లు రాయి చలన మార్గాన్ని, వివిధ స్థానాలలో వేగ సదిశలను గీయండి.
3. రాయి వడి స్థిరమని భావించండి.
4. రాయి వృత్తాకార మార్గం చలిస్తుందని మరియు దాని వేగ దిశ నిరంతరం మారుతుందని గమనిస్తాము.
5. రాయి వడి మాత్రం స్థిరంగా వుంటుంది.
6. వస్తువు వృత్తాకార మార్గంలో చలిస్తున్నప్పుడు దాని వడి స్థిరంగా ఉన్నా, వేగదిశ మాత్రం నిరంతరం మారుతుందని తెలుస్తుంది.

కృత్యం – 7

గాలిలోకి విసిరిన రాయి చలనాన్ని గమనించుట :

7. వది, చలనదిశలు రెండూ మారే సందర్భాన్ని ఒక ఉదాహరణతో వివరించండి.
జవాబు:

1. క్షితిజ తలంతో కొంత కోణం చేసే విధంగా ఒక రాయిని విసరండి.
2. అది ఎలా చలిస్తుందో పరిశీలించి, దాని మార్గాన్ని మరియు వేగ సదిశలను చూపే పటం గీయండి.
3. బంతి వివిధ కాలవ్యవధులలో వివిధ దూరాలు ప్రయాణించి చివరిగా నిశ్చల స్థితికి రావడం గమనిస్తాము. అందువల్ల రాయి వడి స్థిరంగా ఉండదు.
4. పటంలో చూపిన వేగ సదిశల ఆధారంగా, బంతి చలన దిశ కూడా స్థిరంగా ఉండదని తెలుస్తుంది.
5. ఈ కృత్యం ద్వారా వడి, చలన దిశలు రెండూ కూడా నిరంతరం మారుతుండడాన్ని గమనించవచ్చు.

ప్రయోగశాల కృత్యం

8. వాలు తలంపై కదిలే వస్తువు త్వరణం, వేగాలను కొలిచే విధానాన్ని వివరించుము.
జవాబు:
ఉద్దేశం : వాలు తలంపై కదిలే వస్తువు త్వరణం, వేగాలను కొలవడం.

పరికరాలు :
గాజు గోళీలు, ఒకే పరిమాణంలో గల పుస్తకాలు, డిజిటల్ వాచ్, పొడుగాటి ప్లాస్టిక్ గొట్టం, స్టీలు పళ్ళెం.

ప్రయోగపద్ధతి :

1. సుమారు 200 సెం.మీ. పొడవుగల ప్లాస్టిక్ గొట్టాన్ని తీసుకోండి.
2. దానిని పొడవు వెంట చీల్చి వస్తువులు కదిలే కాలువ వంటి మార్గంగా మార్చుకోండి. దీనినే ట్రాక్ అంటాము.
3. ట్రాక్ పై 0 – 200 సెం.మీ. వరకు కొలతలను గుర్తించండి.
4. ట్రాక్ ఒక చివరను పటంలో చూపిన విధంగా పుస్తకాలపై ఉంచండి. రెండవ చివరను నేలపై వుంచండి.
5. రెండవ చివర వద్ద స్టీలు ప్లేటును వుంచండి.
6. ట్రాకను అమర్చేటప్పుడు దాని ‘0’ రీడింగ్ నేలను తాకే వైపు ఉండాలి.
7. ట్రాక్ లో పట్టే పరిమాణంగల గోళీని తీసుకోండి. 40 cm మార్కు నుండి గోళీని విడిచిపెట్టండి.
8. గోళీని విడిచిపెట్టిన వెంటనే డిజిటల్ వాచ్ ను ‘ఆన్’ చేయండి.
9. ఆ గోళీ క్రిందకు వస్తూ నేలపై వుంచిన స్టీలు ప్లేటును ఢీకొని శబ్దం చేస్తుంది. శబ్దం విన్న వెంటనే డిజిటల్ వాచ్ ను ఆపివేయండి.
10. ఇదే ప్రయోగాన్ని (40cm కొలతతో) 2 లేక 3 సార్లు చేసి గణించిన విలువలు పట్టికలో రాయండి.
    
11. పై ప్రయోగాన్ని వేర్వేరు దూరాలతో చేసి వాటికి సంబంధించిన విలువలు పట్టికలో రాయండి.
12. పై విలువలకు s – t గ్రాఫు గీయండి.
13. ఇదే ప్రయోగాన్ని వేరు, వేరు వాలు కోణాల వద్ద చేసి త్వరణాలను కనుక్కోండి.

పరిశీలనలు:

1. వాలు పెరిగిన కొద్దీ త్వరణం పెరుగుతుంది.
2. గాజు గోళీలకు బదులు ఇనుప దిమ్మను వాడినప్పటికీ త్వరణం, వాలుల మధ్య సంబంధం మారదు. (ప్రయోగంలో వచ్చే సంఖ్యాత్మక విలువలు మారవచ్చు.)

SCERT AP 9th Class Physics Study Material Pdf Download 2nd Lesson గమన నియమాలు Textbook Questions and Answers.

AP State Syllabus 9th Class Physical Science 2nd Lesson Questions and Answers గమన నియమాలు

9th Class Physical Science 2nd Lesson గమన నియమాలు Textbook Questions and Answers

అభ్యసనాన్ని మెరుగుపరుచుకోండి

ప్రశ్న 1.
కింది వాటికి కారణాలు వివరించండి. (AS 1)
ఎ) కంబళిని కర్రతో కొడితే, దుమ్ము పైకి లేస్తుంది.
బి) బస్సు పైన వేసిన సామాన్లని తాడుతో కట్టకపోతే పడిపోతాయి.
సి) ఒక పేస్ బౌలర్ బంతి విసిరే ముందు దూరం నుంచి పరిగెత్తుతూ వస్తాడు.
జవాబు:
ఎ) కంబళిని కర్రతో కొడితే అది చలనంలోకి వస్తుంది. కంబళిలోని దుమ్ము కణాలు నిశ్చల జడత్వం వలన నిశ్చలస్థితిలోనే ఉంటాయి కాబట్టి.

బి) బస్సు చలనంలో ఉన్నప్పుడు సామాన్లన్ని కూడా గమన జడత్వం వలన అవి కూడా బస్సు వేగాన్ని కలిగి ఉంటాయి. బస్సు సడన్ గా నిశ్చలస్థితికి రాగానే వస్తువులు మాత్రము గమన జడత్వంలోనే ఉంటాయి కాబట్టి అవి పడిపోతాయి. కనుక.

సి) ఒక పేస్ బౌలర్ బంతి విసిరే ముందు దూరం నుంచి పరుగెత్తుటకు కారణం బంతికి గమన జడత్వంను అందించుటకు
(లేదా) బంతికి ద్రవ్యవేగమును అందించుటకు.

ప్రశ్న 2.
8 కి.గ్రా., 25 కి.గ్రా. ద్రవ్యరాశులు గల రెండు వస్తువులలో ఏ వస్తువు అధిక జడత్వం కలిగి ఉంటుంది? ఎందుకు? (AS 1)
జవాబు:
25 కేజీల ద్రవ్యరాశిగల వస్తువుకు అధిక జడత్వముండును. ఎందుకనగా జడత్వమును నిర్ణయించునది ద్రవ్యరాశి కాబట్టి.

ప్రశ్న 3.
2.2 మీ./సి. వేగంతో కదులుతున్న 6.0 కి.గ్రాల బంతి యొక్క ద్రవ్యవేగం ఎంత? (AS 1)
జవాబు:
బంతి వేగం (V) = 2.2 మీ./సె.
బంతి ద్రవ్యరాశి (m) = 6 కిలోలు
బంతి ద్రవ్యవేగము (P) = mv = 6 × 2.2 = 13.2 కి.గ్రా.మీ/సె.

ప్రశ్న 4.
ఇద్దరు వ్యక్తులు 200N ఫలిత బలంతో ఒక కారుని 3 సెకండ్ల పాటు నెట్టారు. (AS 1)
ఎ) కారుకి అందిన ప్రచోదనం ఎంత?
జవాబు:
వ్యక్తులు ప్రయోగించిన బలం = (F) = 200 N
కాలము = t = 3 సె||
ప్రచోదనము (I) = బలం × కాలం = 200 × 3 = 600 న్యూటన్ – సెకను

బి) కారు ద్రవ్యరాశి 1200 కిలోగ్రాములు అయితే, దాని వేగంలో మార్పు ఎంత?
జవాబు:
కారు ద్రవ్యరాశి = m = 1200 కి.గ్రా.
కారుపై ప్రయోగించిన బలం = 200 N
కాలం = 3 సె.
ప్రచోదనము = ద్రవ్యరాశి × వేగంలోని మార్పు
F × t = m × (v – u)
\(\mathrm{v}-\mathrm{u}=\frac{\mathrm{F} \times \mathrm{t}}{\mathrm{m}}=\frac{200 \times 3}{1200}=\frac{1}{2}=0.5\) మీ./సె.
∴ వేగంలోని మార్పు = v – u = 0.5 మీ./సె.

ప్రశ్న 5.
0.7 కి.గ్రా ద్రవ్యరాశి గల వస్తువులో 3 మీ./సె² త్వరణాన్ని కలుగజేయడానికి ఎంత బలాన్ని ఉపయోగించాలి? (AS 1)
జవాబు:
వస్తువు ద్రవ్యరాశి = m = 0.7 కేజీలు
త్వరణం = a = 3 మీ./సె².
బలం (F) = ద్రవ్యరాశి × త్వరణం = 0.7 × 3 = 2.1 N

ప్రశ్న 6.
5 కి.గ్రా. ద్రవ్యరాశి గల వస్తువు 10 మీ./సె. వేగంతో కదులుతోంది. దానిపై 20 సె.ల పాటు బలాన్ని ప్రయోగించడం వల్ల అది 25 మీ/సె. వేగాన్ని పొందితే, వస్తువుపై ప్రయోగించిన బలం ఎంతో తెల్పండి. (AS 1)
జవాబు:
వస్తువు ద్రవ్యరాశి = m = 5 కి.గ్రా.
వస్తువు తొలి వేగము = u = 10 మీ./సె.
బలం ప్రయోగించబడిన కాలం = t = 20 సె.
వస్తువు తుది వేగము = v = 25 మీ./సె.
వస్తువుపై ప్రయోగించబడిన బలం = F = ma

∴ వస్తువుపై ప్రయోగించబడిన బలం = 3.75 న్యూటర్లు

ప్రశ్న 7.
న్యూటన్ మూడు గమన నియమాలను ఉదాహరణలతో వివరించండి. (AS 1)
జవాబు:
1) న్యూటన్ మొదటి గమన నియమము :
ఫలిత బలం పనిచేయనంతవరకు నిశ్చలస్థితిలో ఉన్న వస్తువు అదే స్థితిలోనూ, సమచలనంలో ఉన్న వస్తువు అదే సమచలనంలోనూ ఉండును.
ఉదా 1 : నిశ్చలంగా ఉన్న ఒక బస్సు ఒక్కసారిగా ముందుకు కదిలితే అందులో నిలబడి ఉన్న ప్రయాణీకుడు వెనుకకు పడతాడు, కారణము బస్సు ఒక్కసారిగా త్వరణాన్ని పొంది ముందుకు కదిలినది, కానీ అందులో వ్యక్తి “జడత్వం” వల్ల తను ముందు ఉన్న స్థానంలోనే ఉండేందుకు ప్రయత్నిస్తాడు. అందువల్లనే వెనక్కి పడిపోతాడు.

ఉదా 2 : బస్సులో ప్రయాణిస్తున్న వ్యక్తి, ఒక్కసారిగా బస్సు ఆగితే ముందుకు పడతాడు, కారణము బస్సు వేగముకు సమాన వేగంతో అతను ప్రయాణిస్తున్నాడు. బస్సు ఒక్కసారిగా ఆగినప్పుడు జడత్వం వలన అతని శరీరం మాత్రం వెంటనే తన గమనస్థితిని మార్చుకోలేదు. అందుకే ముందుకు పడతాడు.

2) రెండవ గమన నియమము : వస్తువు ద్రవ్యవేగంలో మార్పు రేటు, దానిపై పనిచేసే ఫలిత బలానికి అనులోమానుపాతంలో ఉంటుంది. దాని దిశ ఫలిత బలదిశలో ఉంటుంది.
ఉదా 1 : సిమెంట్ గచ్చుపై కంటే ఇసుక నేల మీద దూకడం సురక్షితము. ఎందుకనగా మృదువైన, మెత్తని తలాలు వస్తువుని ఆపడంలో ఎక్కువ సమయం తీసుకోవడం వల్ల “ఆపే దూరం” ఎక్కువగా ఉంటుంది. ఈ విధంగా ద్రవ్యవేగంలో మార్పు రేటు తక్కువగా ఉంటుంది. ఫలితంగా కాలికి తక్కువ దెబ్బ తగులుతుంది.

ఉదా 2 : వేగంగా వస్తున్న క్రికెట్ బంతిని “క్యాచ్” చేసేటప్పుడు ఆ వ్యక్తి తన చేతులను వెనుకకు లాగుతాడు. ఈ సందర్భంలో అతడు బంతి వేగాన్ని తగ్గించడానికి ఎక్కువ సమయం తీసుకుంటాడు.

ఇలా చేయడం వల్ల బంతి ద్రవ్యవేగంలో మార్పు రేటు తక్కువగా ఉంటుంది. ఫలితంగా చేతులపై బంతి ప్రయోగించే బలం తగ్గుతుంది.

3) మూడవ గమన నియమము : ఎల్లప్పుడూ చర్యకు దానికి సమానంగా మరియు వ్యతిరేక శిశలో ఉంటుంది. ఇది దృఢ వస్తువులకు మాత్రమే. చర్య, ప్రతిచర్య జంట బలాలు. వాటి పరిమాణం సమానం. దిశలో వ్యతిరేకం మరియు వేరు వేరు వస్తువులపై పని చేస్తాయి. కావున అవి ఎప్పుడూ రద్దు కావు.

వివరణ:

1. రెండు వస్తువులు పరస్పరం బలాలు ప్రయోగించుకుంటున్నప్పుడు
2. ప్రతిక్రియ జరిపేటప్పుడు, A వస్తువు B వస్తువుపై కలుగజేసే బలం FAB (చర్య)
3. B వస్తువు A వస్తువుపై కలుగజేసే బలం FRA (ప్రతిచర్య)
4. న్యూటన్ మూడో గమన నియమం వలన ఈ రెండు బలాలు పరిమాణంలో సమానంగాను, దిశలో వ్యతిరేకంగాను, ఉంటాయి.
   F_AB = – F_BA
   చర్య = ప్రతిచర్య
5. దీనిని బట్య జంట బలాలు ఒకే వస్తువు పై కాక, రెండు వేర్వేరు వస్తువులపై పనిచేస్తాయి.
   ఉదా 1:
   i) పక్షులు ఎగిరేటప్పుడు వాటి రెక్కలతో గాలిని కిందకి నెడతాయి. అప్పుడు గాలి కూడా పక్షిని వ్యతిరేకదిశలో (పైకి) నెడుతుంది.
   ii) రెక్కలు గాలి మీద ప్రయోగించే బలం, గాలి పక్షి రెక్కలపై ప్రయోగించే బలాలు రెండూ సమాన పరిమాణంలో, వ్యతిరేక దిశలో ఉంటాయి.
   ఉదా 2 :
   నీటిలో ఈదుతున్న చేప నీటిని వెనక్కి నీరు చేపని ముందుకు నెట్టే బలం రెండూ పరిమాణంలో సమానంగా, దిశ పరంగా వ్యతిరేకంగా ఉంటాయి. నీరు చేపపై కలిగించే బలం వల్ల చేప ముందుకు కదులుతుంది.

ప్రశ్న 8.
వేగంగా వెళ్తున్న బస్సు అద్దాన్ని ఒక ఈగ గుద్దుకుంటే, బస్సు మీద, ఈగ మీద ఒకే బలం ప్రయోగించబడుతుందా? ఎందుకు? (AS 1, AS 7)
జవాబు:
న్యూటన్ మూడవ గమన నియమం ప్రకారం బస్సు మీద, ఈగ మీద ఒకే బలం ప్రయోగించబడుతుంది.

ప్రశ్న 9.
ఒక బిండిని గుర్రం లాగదాన్ని ‘దివ్య’ చూసింది. గుర్రం ఎంత బలంతో బండిని లాగుతుందో, అంతే బలంతో బండి సర్రాన్ని కూడా లాగుతుందని ఆమె భావించింది. “మరి బండి ఎలా కదులుతుంది?” అని ఆమెకు సందేహం కలిగింది. అంతేగాక ఆమె మదిలో ఎన్నో ప్రశ్నలు తలెత్తాయి. ఆ ప్రశ్నలేవో ఊహించండి. (AS 2)
జవాబు:

1. గుర్రం ఎంత బలాన్ని నేలపై ఉపయోగిస్తుంది?
2. గుర్రంకు – బండికి మధ్య ఏ నియమం పనిచేస్తుంది?
3. గుర్రం ముందుకు ఎందుకు వంగవలసి వస్తుంది?
4. గుర్రం తక్కువ బలాన్ని ఉపయోగిస్తే బండి కదలదా?
5. సైకిలులాగా, ఎందుకు తేలికగా గుర్రపు బండి కదలటం లేదు?
6. మరి బండి ఎలా కదులుతుంది?

ప్రశ్న 10.
గెలీలియో ప్రకారం ఫలిత బలం పని చేయనంతవరకు, వస్తువు దాని స్థితిలోనే కొనసాగుతుందని మనకు తెలుసు. అదే విధంగా అరిస్టాటిల్ ప్రకారం ప్రతి వస్తువు కదులుతూ దానంతట అదే నిశ్చలస్థితికి వస్తుందని కూడా మనకు తెలుసు. వీటిలో ఏది సరైనదో మనం చెప్పగలమా? గెలీలియో తెలిపిన నియమాన్ని మీరు ఏ విధంగా అభినందిస్తారు? (AS 6)
జవాబు:
గెలీలియో, అరిస్టాటిల్ నియమాలలో ఏది సరైనదో మనకు చెప్పడం సాధ్యమే.

1. భూమి మీద కదులుతున్న ఏ వస్తువైనా క్రమంగా నిశ్చలస్థితికి వస్తుందని మన ప్రాచీన తత్త్వవేత్తల భావన.
2. ఆ కాలంలో గొప్ప తత్త్వవేత్త అయిన అరిస్టాటిల్ కూడా ఇలాగే ఆలోచించి, కదిలే ఏ వస్తువైనా చివరకు నిశ్చలస్థితికి రావాలి కాబట్టి, వాటిపై ఎటువంటి వివరణా అవసరం లేదని భావించాడు.
3. ఆ సమయంలో గెలీలియో తన ఆలోచనాత్మక ప్రయోగాలను నునుపుతలం గల వాలు బల్లలపై చేశాడు.
4. గెలీలియో, తలం ఎంత నునుపుగా ఉంటే వదిలిన గోళీ అంత దూరం ప్రయాణం చేస్తుందని గమనించాడు. ఏదీ అడ్డురాకపోతే గోళీ అనంత దూరం ప్రయాణిస్తుందని వివరించాడు.
5. ఈ విధంగా ఏ బాహ్య బలం పనిచేయనంత వరకు కదులుతున్న వస్తువు అదే గమన స్థితిలో ఉంటుందని చెప్పడం ద్వారా గెలీలియో ఆధునిక విజ్ఞానశాస్త్రానికి తెరతీశాడు. కావున నేను గెలీలియో ప్రాథమిక ప్రయోగాలను పరిశీలించి, అతనిని అభినందిస్తున్నాను. .

ప్రశ్న 11.
20 మీ./సె. సమ వడితో ఒక కారు పడమర వైపు ప్రయాణిస్తుంటే, దానిపై గల ఫలిత బలం ఎంత? (AS 1, AS 7)
జవాబు:
కారు వడి = 20 మీ./సె.
కారు పడమర వైపు సమ వేగంతో ప్రయాణిస్తుంది, కావున త్వరణము శూన్యము.
∴ ఫలిత బలము = శూన్యము.

ప్రశ్న 12.
30 కి.గ్రాల ద్రవ్యరాశి గల ఒక వ్యక్తి 450 న్యూటన్ల బలాన్ని భరించగల ‘తాడు’ సహాయంతో కొండ ఎక్కుతున్నాడు. అతను సురక్షితంగా ఎక్కడానికి కావల్సిన గరిష్ఠ త్వరణం ఎంత? (AS 1, AS 7)
జవాబు:
వస్తువు ద్రవ్యరాశి = m = 30 kg
తాడు తన్యత (T) = 450 న్యూ.
త్వరణం = a = ?
T = N = ma
450 = 30 xa
450 a = 30 = 15 మీ./సె

∴ గరిష్ఠ త్వరణం = a = 15 మీ./సె.

ప్రశ్న 13.
కదులుతున్న రైలులో ఉన్న ఒక ప్రయాణికుడు ఒక నాణాన్ని నిట్ట నిలువుగా పైకి విసిరిన, అది అతని వెనుకవైపు పడింది. ఆ రైలు ఎటువంటి చలనంలో ఉంది? (AS 7)
ఎ) ధన త్వరణం బి) సమచలనం సి) ఋణ త్వరణం డి) వృత్తాకార చలనం
జవాబు:
ఎ) ధన త్వరణం.

ప్రశ్న 14.
నిశ్చలస్థితిలో ఉన్న 1.4 కి.గ్రా.ల ద్రవ్యరాశి గల వస్తువు మీద 0.2 సెకన్ల పాటు బలం ప్రయోగించబడింది. బలం ప్రయోగించడం ఆపిన తర్వాత ఆ వస్తువు 2 సెకన్లలో 4 మీ. దూరం కదిలింది. ప్రయోగించిన బల పరిమాణం ఎంత? (AS 1)
జవాబు:
వస్తువు ద్రవ్యరాశి = m = 1.4 కి.గ్రా.
బలం ప్రయోగించిన కాలం = t₁ = 0.2 సె||
బల ప్రయోగం ఆపిన తర్వాత
వస్తువు ప్రయాణించిన దూరం = 4 మీ.
వస్తువు ప్రయాణించిన కాలం = t₂ = 2 సె||
ప్రయోగించబడిన బలం (F) = m . a

∴ ప్రయోగించబడిన బలం = F = 14 న్యూ.

ప్రశ్న 15.
పటాలలో ఉన్న 2 కి.గ్రా.ల ద్రవ్యరాశి గల వస్తువు యొక్క త్వరణాన్ని కనుక్కోండి. (AS 1)

జవాబు:
1) 2 × 10 = 20 kg. ద్రవ్యరాశిపై, 30 N బలం క్రింది వైపు పనిచేస్తుంది.

ప్రశ్న 16.
రెండు రబ్బరు బాండ్ల సహాయంతో సాగదీసి వదిలినపుడు ఒక వస్తువు 2 మీ./సె². త్వరణాన్ని పొందింది. ఇలా చేయడంలో రబ్బరు బాండు ఒక ప్రమాణ పొడవుకి సాగిందనుకుందాం. రెండోసారి నాలుగు రబ్బరు బాండ్ల సహాయంతో రెట్టింపు ద్రవ్యరాశి గల వస్తువును లాగితే అది పొందే త్వరణం ఎంత? (రబ్బరు బాండ్లను పైన తెలిపిన ప్రమాణ పొడవుకు సాగదీయాలి.) (AS 1)
జవాబు:
మొదటిసారి రెండు రబ్బరు బాండ్ల సహాయంతో సాగదీసి వదిలినపుడు వస్తువు పొందు త్వరణం 2 మీ/సె².
రెండవసారి నాలుగు రబ్బరు బాండ్ల సహాయంతో రెట్టింపు ద్రవ్యరాశిగల వస్తువును లాగితే పొందు త్వరణం, రెండు సందర్భాలలో ప్రయోగించబడిన బలం సమానము. కావున అవి ఒకే త్వరణాన్ని కలిగి ఉంటాయి.
∴ కావలసిన త్వరణం = 2 మీ/సె².

ప్రశ్న 17.
ఒక గుర్రం స్థిర వడితో బండిని లాగాలంటే అది ఎల్లప్పుడూ నేలపై బలాన్ని ప్రయోగిస్తూ ఉండాలి. ఎందుకో వివరించండి. (AS 1)
జవాబు:

1. గుర్రం, బండిపై బలాన్ని ప్రయోగించగానే, బండి చక్రాలకు రోడ్డుకి మధ్యన గల ఘర్షణ బలం గుర్రం ఉపయోగించిన బలానికి వ్యతిరేకంగా పనిచేస్తుంది.
2. గుర్రం స్థిరవడితో బండిని లాగాలంటే అది ఎల్లప్పుడూ ఘర్షణ బలానికి సమానమైన బలాన్ని బండిపై ప్రయోగించాలి.

ప్రశ్న 18.
5 N బలం m₁ ద్రవ్యరాశి గల వస్తువులో 8 మీ./సె². త్వరణాన్ని, m₂ ద్రవ్యరాశి గల వస్తువులో 24 మీ/సె². త్వరణాన్ని తీసుకురాగలుగుతుంది. రెండు వస్తువులను జతచేసిన వ్యవస్థపై అదే బలాన్ని ప్రయోగిస్తే అది పొందే త్వరణం ఎంత? (AS 1)
జవాబు:
మొదటి వస్తువుపై ప్రయోగించబడిన బలం = F = 5 N
మొదటి వస్తువు త్వరణం = a = 8 మీ./సె².
న్యూటన్ 2వ నియమం ప్రకారం F = m₁a ⇒ m₁ = F/a = \(\frac{5}{8}\)
రెండవ వస్తువుపై ప్రయోగించబడిన బలం = F = 5N
రెండవ వస్తువు త్వరణం = a = 24 మీ/సె²
న్యూటన్ 2వ గమన నియమం ప్రకారం F = m₂a ⇒ m₂ = \(\frac{\mathrm{F}}{\mathrm{a}}=\frac{5}{24}\)
ఈ రెండు వస్తువులను జతచేసిన వ్యవస్థ కావున

రెండు వస్తువులను జత చేసిన వ్యవస్థపై ఒకే బలం ప్రయోగించడం వలన ఏర్పడు త్వరణము 6 మీ./సె². అగును.

ప్రశ్న 19.
400 గ్రా. ద్రవ్యరాశి గల సుత్తి 30 మీ./సె. వేగంతో కదులుతూ ఒక మేకును తాకింది. మేకు సుత్తిని 0.01 సె.కాలంలో నిశ్చలస్థితికి తీసుకురాగలిగితే, మేకు సుత్తి మీద ప్రయోగించే బలం ఎంత? (AS 1)
జవాబు:
సుత్తి ద్రవ్యరాశి = m = 400 గ్రా = 0.4 కి.గ్రా
సుత్తి తొలివేగం = u = 30 మీ./సె.
సుత్తి తుదివేగం = V = 0
మేకును సుత్తి తాకిన కాలం = t = 0.01 సె.

∴ మేకు వ్యతిరేకదిశలో సుత్తి పై 1200 న్యూ. బలం కలుగజేయును.

ప్రశ్న 20.
పటంలో ఒక వ్యవస్థ చూపబడింది.
ఈ వ్యవస్థలోని చెక్కదిమ్మల త్వరణాన్ని, తాడులో తన్యతను కనుక్కోండి. (AS 1)

g = 10 మీ/సె² గా తీసుకోండి.
జవాబు:
వ్యవస్థలో m₁ = m₂ = 3 కి.గ్రా.
త్వరణం = g = 10 మీ/సె²

ప్రశ్న 21.
పటంలో చూపిన విధంగా ఘర్షణ లేని సమాంతర తలంపై మూడు చెక్కదిమ్మలను అమర్చి 30 న్యూటన్ల బలంతో తాడుని లాగుతున్నారు. ప్రతి చెక్కదిమ్మ ద్రవ్యరాశి 10 కి.గ్రా. అయితే ప్రతి చెక్కదిమ్మ యొక్క త్వరణం ఎంత? చెక్కదిమ్మలను కలిపిన తాడులో తన్యత ఎంత? (AS 1)

జవాబు:
మూడు చెక్కదిమ్మల ద్రవ్యరాశులు m₁, m₂ మరియు m₃ లనుకొనుము.
∴ m₁ = m₂ = m₃ = 10 కి.గ్రా.
చెక్కదిమ్మలపై పనిచేయు బలం = F = 30 N

తాడులో తన్యతలు T₁ మరియు T₂ లనుకొనుము.
మొదటి సందర్భంలో తన్యత = T₁ = m₁ × a = F
= 10 × 1 = 10 N
రెండవ సందర్భంలో తన్యత = T₂ = F = (m₁ + m₂) a
= (10+ 10) (1) = 20 N

ప్రశ్న 22.
టేబుల్ చివర ఒక దీర్ఘ చతురస్రాకారంలో కత్తిరించిన కాగితాన్ని పెట్టి దానిపై మందమైన ఐదు రూపాయల బిళ్లని పటంలో చూపినట్లు నిలబెట్టండి. మీ వేలితో వేగంగా కాగితాన్ని నెట్టండి. ఈ కృత్యాన్ని జడత్వంతో ఏ విధంగా వివరించగలవు? (AS 2)

జవాబు:
కాగితాన్ని వేలితో గట్టిగా లాగడం వలన కాగితం చలనములోనికి వస్తుంది. ఐదు రూపాయల బిళ్ల నిశ్చల జడత్వం వలన చలనములోనికి రాకుండానే టేబుల్ పై ఉంటుంది.

ప్రశ్న 23.
ఏకరీతి గల రెండు గోళాలను తీసుకోండి. గోళాలు కదిలేందుకు వీలుగా మీ నోటు పుస్తకాలను రెండువైపులా పెట్టి చిన్న దారిని ఏర్పాటు చేయండి. ఇప్పుడు దారిలో ఒక గోళాన్ని పెట్టి, రెండవ గోళీతో కొట్టండి. (క్యారంబోర్డు స్ట్రైకర్ తో కొట్టినట్లు) అలాగే ఒక గోళీ స్థానంలో రెండు, మూడు, నాలుగు గోళీలను పెట్టి గోళీలను కొట్టింది. పరిశీలనల నుంచి మీరు ఏం వివరించగలరు? (AS 5)
జవాబు:
న్యూటన్ మూడవ గమన నియమం ప్రకారం ఒక గోళీ రెండవ గోళీ పై బలాన్ని చూపగా, రెండవ గోళీ మూడవ గోళీ పై వ్యతిరేక దిశలో బలాన్ని చూపుతుంది.
చర్య = – ప్రతిచర్య కావున
అదే విధముగా 3వ గోళీ 4వ గోళీ పై, 4వ గోళీ 3వ గోళీ పై చర్యా, ప్రతిచర్యలకు లోనవుతాయి.

ప్రశ్న 24.
1500 కి.గ్రాల ద్రవ్యరాశి గల వాహనం 1.7 మీ/సె². ఋణ త్వరణంలో ఆగడానికి రోడ్డుకి, వాహనానికి మధ్య గల ఇలం ఎంత ఉండాలి? (AS 7)
జవాబు:
వాహన ద్రవ్యరాశి = m = 1500 కి.గ్రా.
ఋణ త్వరణము = – a = – 1.7 మీ/సె².
బలము (F) = ద్రవ్యరాశి × త్వరణం = 1500 × – 1.7 = – 2550 N
∴ రోడ్డుకి, వాహనానికి మధ్యన గల బలం 2550 N లు చలనదిశకు వ్యతిరేక దిశలో పనిచేయును.

ప్రశ్న 25.
ఎత్తులో ఉన్న ఒక హోపర్ ఇసుకను జారవేసే యంత్రానికి కింద ఉన్న ట్రక్కు 20 మీ/సి. సమవేగంతో వెళ్తుంది. సెకనుకు 20 కిలోల చొప్పున ఇసుక ట్రక్కు మీద పడుతుంటే, ఇసుక పడటం వల్ల ట్రక్కు మీద ప్రయోగింపబడిన బలం ఎంత? (AS 7)
జవాబు:
ట్రక్కు వేగము = 20 మీ/సె.
హోపర్ సెకనుకు 20 కిలోల చొప్పున ఇసుకను ట్రక్ పై వేస్తున్నది.
న్యూటన్ రెండవ నియమము ప్రకారం
బలం = ద్రవ్యరాశి × వేగంలోని మార్పురేటు

కాని ఇసుకను కొంత ఎత్తు నుండి జారవేసే హోపర్ వంటి పరికరాల విషయంలో దాని వేగంలో మార్పుండదు, కాని అది వేసే ఇసుక పరిమాణంలో సెకను, సెకనుకి మార్పుండును. అనగా వేగం స్థిరము, ద్రవ్యరాశిలో మార్పు వస్తుంది.
∴ F = వేగము × ద్రవ్యరాశిలో మార్పురేటు.
F = v × \(\frac{\Delta \mathrm{m}}{\Delta \mathrm{t}}\) = 20 × 20
F = 400 న్యూ.
∴ ఇసుక పడటం వల్ల ట్రక్కుపై ప్రయోగించబడిన బలం (F) = 400 న్యూ.

ప్రశ్న 26.
నిశ్చలస్థితిలో ఉన్న ఇద్దరు స్కేటింగ్ చేసే వ్యక్తులు ఒకరినొకరు తోసుకున్నారు. వీరిలో 60 కి.గ్రా. ద్రవ్యరాశి గల వ్యక్తి 2 మీ/సె. వేగాన్ని పొందితే, 40 కి.గ్రా. ద్రవ్యరాశి గల రెండవ వ్యక్తి పొందే వేగం ఎంత? (AS 7)
జవాబు:
వ్యవస్థలో తొలి ద్రవ్యవేగం = శూన్యము = m₁u₁ + m₂u₂
మొదటి వ్యక్తి ద్రవ్యరాశి = m₁ = 60 కి.గ్రా,
మొదటి వ్యక్తి తుది వేగము = v₁ = 2 మీ./సె.
రెండవ వ్యక్తి ద్రవ్యరాశి = m₂ = 40 కి.గ్రా.
రెండవ వ్యక్తి తుది వేగము = v₂ = ?
∴ ద్రవ్యవేగ నిత్యత్వ నియమం ప్రకారం
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
m₁v₁ + m₂v₂ = 0
m₂v₂ = -m₁v₁

∴ రెండవ వ్యక్తి వ్యతిరేక దిశలో 3 మీ./సె. త్వరణాన్ని కలిగి ఉన్నాడు.

ప్రశ్న 27.
m ద్రవ్యరాశి గల బంతి ‘V’ వడితో గోడను లంబంగా ఢీకొట్టి అదే వడితో వెనుకకు మరలింది. గోడ బంతిపై ప్రయోగించే సరాసరి బలాన్ని మరియు బల దిశను కనుక్కోండి. (అభిఘాత సమయం ‘t’) (AS 7)
జవాబు:
బంతి ద్రవ్యరాశి = m
బంతి తొలివడి = u = – v (↑ ↑)
బంతి తుదివడి = v= v (అదే వడి కావున దిశ వేరే)
ప్రయోగ కాలము = 1 అనుకొనుము.
న్యూటన్ రెండవ గమన నియమం ప్రకారం
∴ F = ma

బలదిశ గోడ నుండి దూరముగా ఉండును.

9th Class Physical Science 2nd Lesson గమన నియమాలు Textbook InText Questions and Answers

9th Class Physical Science Textbook Page No. 24

ప్రశ్న 1.
టేబుల్ మీది గుడ్డను ఒక్కసారిగా లాగిన, దాని మీద పెట్టిన పాత్రలు దాదాపు కదలకుండా అలాగే ఉండేలా చేసే ట్రిక్ (గారదీ)ని మీరు చూసే ఉంటారు ! ఈ గారడీని సమర్థవంతంగా నిర్వహించడానికి ఏం కావాలి?
జవాబు:
ఒక టేబుల్ క్లాత్, ఏదైనా ఒక వస్తువు కావాలి. ఈ గారడీ చేసే వ్యక్తి గుడ్డను చాలా నైపుణ్యంతో టేబుల్ పై నుండి లాగాలి.

ప్రశ్న 2.
ఎటువంటి గుధ ఉపయోగిస్తావు? దళసరి కాన్వాస్ గుడ్డనా లేదా పల్చని సిల్కు గుడ్డనా?
జవాబు:
దళసరి కాన్వాస్ గుడ్డను ఈ గారడీ చేయడానికి వాడాలి.

ప్రశ్న 3.
టేబుల్ గుడ్డపై పెట్టిన పాత్రలు అధిక ద్రవ్యరాశిని కలిగి ఉండాలా? తక్కువ ద్రవ్యరాశిని కలిగి ఉండాలా?
జవాబు:
టేబుల్ గుడ్డపై పెట్టిన పాత్రలు కొద్దిగా ఎక్కువ ద్రవ్యరాశిని కలిగి ఉండాలి. తేలికపాటి వస్తువులైన ప్లాస్టిక్ కప్పులు, స్పాంజ్ లు వాడకూడదు.

ప్రశ్న 4.
గుడ్డను ఒక్కసారిగా ఎక్కువ బలాన్ని ప్రయోగించి లాగాలా? లేదా సున్నితంగా, నిలకడగా బలాన్ని ప్రయోగించాల్సి ఉంటుందా?
జవాబు:
గుడ్డను తక్కువ బలంతో ఒక్కసారిగా లాగండి.

ప్రశ్న 5.
10 కి.మీ./సె. వేగంతో శూన్యంలో ప్రయాణిస్తున్న రాకెట్ నుండి విడిపోయిన చిన్న వస్తువు యొక్క వేగం ఎంత ఉంటుంది?
జవాబు:
నిర్దిష్ట వేగంతో చలిస్తున్న ఒక్క వస్తువు నుండి విడిపోయిన మరొక చిన్న వస్తువు కూడా అదే వేగంతో ప్రయాణిస్తుంది. కావున 10కి.మీ/ సెకను వేగంతో శూన్యంలో ప్రయాణిస్తున్న రాకెట్ నుండి విడిపోయిన చిన్న వస్తువు యొక్క వేగము కూడా 10కి.మీ/సెకన్ ఉంటుంది.

9th Class Physical Science Textbook Page No. 27

ప్రశ్న 6.
ప్రక్క పటాన్ని గమనించండి. 80 కి.గ్రా.ల ద్రవ్యరాశి గల దృఢమైన వ్యక్తి పటంలో చూపిన విధంగా గరిష్ఠంగా ఎంత బరువును పైకి ఎత్తగలడు?

జవాబు:
వ్యక్తి అతని బరువుకు సమానమైన భారమును ఎత్తగలడు. ఎందుకనగా ఫలితబలము శూన్యము.
కావున T – mg = 0 = mg = T
ఇక్కడ g = 10, ద్రవ్యరాశి = 80 కి.గ్రా.
∴ T = 80 × 10 = 800 N

ప్రశ్న 7.
తిరుగుతున్న సీలింగ్ ఫ్యాన్ యొక్క ద్రవ్యవేగం ఎంత?
జవాబు:
ద్రవ్యవేగము = ద్రవ్యము X వేగము
∆t = m (v – u)
ఇక్కడ వస్తువు తొలివేగము (u) మరియు తుది వేగము (v)లు సమానము కావున m (v – u) = ∆t = 0
∴ తిరుగుతున్న ఫ్యాను యొక్క ద్రవ్యవేగము శూన్యము.

ప్రశ్న 8.
ఫలిత బలం లేనప్పుడు వస్తువు వక్రమార్గంలో చలించగలదా?
జవాబు:
చలించగలదు. ఉదాహరణకు మనము ఒక వక్రమార్గములో ప్రయాణించుచున్నపుడు, అభికేంద్ర బలము వలన మనము ఆకర్షించబడతాము. అదే సమయంలో మనపై అపకేంద్రబలము పనిచేయును. ఈ ఫలితబలము వలన మన వాహన టైర్లకు, రోడ్డుకు మధ్య ఘర్షణ బలము ఏర్పడును.

ప్రశ్న 9.
తాడు యొక్క ద్రవ్యరాశిని విస్మరించినప్పుడు దానిలో ఉన్న తన్యత ఏకరీతిగా ఉంటుందని ఎలా నిరూపిస్తావు?
జవాబు:
ఒక తాడుకు రాయిని కట్టి నీటిలో వ్రేలాడదీసినపుడు దాని ద్రవ్యరాశి గురుత్వాకర్షణ (8)పై ఆధారపడును. అదే విధముగా అదే రాయిని గాలిలో వ్రేలాడదీసిన దాని ద్రవ్యరాశి కూడా ‘g’ పై ఆధారపడును. దీనిని బట్టి తాడు యొక్క ద్రవ్యరాశిని విస్మరించినప్పుడు దానిలో ఉన్న తన్యత ఏకరీతిగా ఉంటుందని గ్రహించవచ్చును.

9th Class Physical Science Textbook Page No. 31

ప్రశ్న 10.
ఒక బంతిపై భూమి ప్రయోగించే బలం 8N అయితే, ఆ బంతి భూమిపై ప్రయోగించే బలం ఎంత?
జవాబు:
బంతిపై ప్రయోగించిన బలం = 8N
బంతి భూమిపై ప్రయోగించే బలం = బంతిపై ప్రయోగించిన బలం = 8N

ప్రశ్న 11.
ఒక చెక్క దిమ్మ క్షితిజ సమాంతర తలంపై ఉంది. దానిపై కిందికి లాగే అభిలంబ బలం గురుత్వాకర్షణ బలం, పైకి నెట్టే అభిలంబ బలం పనిచేస్తాయి. ఆ రెండు బలాలు పరిమాణంలో సమానంగా ఉంటూ, వ్యతిరేక దిశలలో ఉంటాయా? ఆ బలాల జతను చర్య – ప్రతిచర్య జతగా చెప్పవచ్చా? మీ స్నేహితులతో చర్చించండి.

జవాబు:

1. చెక్కదిమ్మపై గురుత్వాకర్షణ బలం, పైకి నెట్లే అభిలంబ బలం సమానంగా మరియు వ్యతిరేక దిశలలో ఉంటాయి.
2. ఆ బలాల జతను చర్య – ప్రతిచర్య జతగా చెప్పవచ్చును.

ప్రశ్న 12.
మంటలను ఆర్పడానికి ఉపయోగించే గొట్టాల నుండి అతి వేగంగా నీరు బయటకు వస్తుంది. ఆ గొట్టాలను పట్టుకోవడం చాలా కష్టం. ఎందుకు?
జవాబు:
మంటలను ఆర్పడానికి వాడు గొట్టాలను పట్టుకున్నపుడు అది మన చేతులపై బలాన్ని కలుగజేస్తుంది. ప్రతిచర్యగా మనము ఆ గొట్టముపై బలంను ప్రదర్శించవలెనన్న సాధ్యపడదు. కావున ఆ గొట్టాలను పట్టుకోవడం చాలా కష్టం.

9th Class Physical Science Textbook Page No. 33

ప్రశ్న 13.
భూవాతావరణంలోకి ప్రవేశించిన ఒక ఉల్క మండిపోయింది. అలా మండినప్పుడు దాని ద్రవ్యవేగము ఏమైనట్లు?
జవాబు:
భూవాతావరణంలోకి రాగానే ఉల్క మండిపోవటం వలన దాని ద్రవ్యవేగము శూన్యమవుతుంది.

ప్రశ్న 14.
బంతిని నిట్టనిలువుగా పైకి విసిరినప్పుడు, భూ ఉపరితలం నీ కాళ్లపై ప్రయోగించే అభిలంబ బలంలో ఏమైనా మార్పు వస్తుందా?
జవాబు:
నా శరీరాన్ని తుల్యము (balance) చేయుటకు భూఉపరితలము ప్రదర్శించు అభిలంబ బలము పెరుగును.

ప్రశ్న 15.
చెట్టుపై నుండి జారిపడిన కొబ్బరికాయ నేలని తాకి ఆగిపోయింది. దాని ద్రవ్యవేగం ఏమైందని చెప్పగలం?
జవాబు:
కొబ్బరికాయ నేలను తాకి ఆగిపోవుట వలన దాని ద్రవ్యవేగము శూన్యము అగును.

ప్రశ్న 16.
కొన్ని కార్లలో రక్షణ కొరకు గాలి సంచులు వాడతారు. ఎందుకు?
జవాబు:
గాలి సంచులుగల కార్లకు ప్రమాదములు జరిగినపుడు ప్రచోదన కాలము పెరుగుట వలన కారు నడుపు వ్యక్తిపై ప్రయోగించబడు బలము తగ్గి, అతను ప్రాణహాని నుండి రక్షించబడతాడు.

9th Class Physical Science Textbook Page No. 24

ప్రశ్న 17.
అన్ని వస్తువులూ ఒకే జడత్వాన్ని కలిగి ఉంటాయా? వస్తువుల జడత్వాన్ని నిర్ణయించే అంశాలు ఏవి? ఉదాహరణతో వివరించండి.
జవాబు:
అన్ని వస్తువులూ ఒకే జడత్వాన్ని ప్రదర్శించవు. జడత్వమును నిర్ణయించు అంశము ఆ వస్తువుకుండే ద్రవ్యరాశి,

ఉదాహరణ :

1. మైదానంలో ఒక ఫుట్ బాల్ ను కాలితో తన్నినట్లయితే, అది కొంత వేగంతో తన్నిన దిశలో వెళ్తుంది.
2. అదే పరిమాణము గల ఒక రాయినిగాని తన్నినట్లయితే దాని చలనంలో ఎటువంటి మార్పును గమనించవు మరియు నీ కాలికి దెబ్బ తగులుతుంది.
3. దీనికి కారణము రాయికి అధిక ద్రవ్యరాశి ఉండటం వలన బంతికి తక్కువ ద్రవ్యరాశి ఉండటం వలన త్వరగా స్థితిని మార్చుకోగలిగినది.
4. ఈ విధంగా పదార్థ ద్రవ్యరాశి వస్తు జడత్వంను నిర్ణయిస్తుంది.

9th Class Physical Science Textbook Page No. 32

ప్రశ్న 18.
పోల్ వాల్ట్ ఆడేవారు స్పాంజ్ తో చేసిన పరుపు మీద దూకుతారు. ఎందుకు?
జవాబు:
స్పాంజ్ పరుపుపై ఫలిత ద్రవ్యవేగము తక్కువగా ఉండును. కావున పోల్ వాల్ట్ ఆడేవారిపై తక్కువ ప్రతిచర్యా బలం పని చేస్తుంది.

ప్రశ్న 19.
ఇసుక నేల మీద దూకటం సురక్షితమా లేదా సిమెంటు గచ్చుపై దూకటం సురక్షితమా? ఎందుకు?
జవాబు:
సిమెంటు గచ్చుపై కన్నా ఇసుకపై దూకటం సురక్షితము. ఎందుకంటే మృదువైన మెత్తటి తలాలు వస్తువుని ఆపటంలో ఎక్కువ సమయాన్ని తీసుకోవటం వల్ల ఆ పేదూరం ఎక్కువగా ఉంటుంది.

ఉదాహరణ సమస్యలు

9th Class Physical Science Textbook Page No. 25

ప్రశ్న 1.
సమతలంపై ఉంచిన ‘M’ ద్రవ్యరాశి గల వస్తువు పై క్షితిజ సమాంతరంగా 100 బలం నిరంతరంగా ప్రయోగించడం వల్ల ఆ వస్తువు నిలకడగా కదులుతుంది.
ఎ) స్వేచ్ఛా వస్తు పటాన్ని (FBD) (ఒక నిర్దిష్ట సమయం వద్ద ఆ వస్తువుపై పనిచేస్తున్న అన్ని బలాలను చూపే పటం) గీయండి.
బి) ఘర్షణ విలువ ఎంత?
సాధన:

వస్తువు నిలకడగా కదులుతుందని ఇవ్వబడింది. అంటే క్షితిజ సమాంతర, క్షితిజ లంబ దిశలో ఆ వస్తువుపై పనిచేసే ఫలిత బలం శూన్యం అని అర్ధం.

ఆ వస్తువుపై క్షితిజ సమాంతర దిశలో ఘర్షణ బలం (f), నెట్టిన బలం (F). లు పనిచేస్తున్నాయి.

క్షితిజ సమాంతర దిశలో ఫలిత బలం
F_{net, x} = 0 అని మనకు తెలుసు.
F + (-f) = 0
F = f

కాబట్టి ఆ వస్తువుపై పనిచేసే ఘర్షణ బలం = 10 న్యూటన్లు.

9th Class Physical Science Textbook Page No. 27

ప్రశ్న 2.
1కి.గ్రా. ద్రవ్యరాశి మరియు 1 మీటరు పొడవు గల చాప గచ్చుపై పరచబడి ఉంది. చాప ఒక చివరను పట్టుకుని దాని – పొడవు వెంట రెండవ చివరివైపు 1 మీ/సె. స్థిర వడితో చాప మొత్తం చలనంలోకి వచ్చేంత వరకు చాప పూర్తిగా తిరగబడేంత వరకు) లాగాలంటే చాపపై ఎంత బలాన్ని ప్రయోగించాలి?
సాధన:

పటం 10లో చూపిన విధంగా చాప చివర బాగాన్ని 1 మీ/సె. స్థిర వడితో లాగుతున్నప్పుడు చలనం లోకి వచ్చే చాప భాగపు ద్రవ్యరాశి క్రమంగా పెరుగుతూ ఉంటుంది. కాబట్టి ద్రవ్యరాశి స్థిరంగా ఉండదు.

మొత్తం చాప చలనంలోకి రావడానికి పట్టే సమయం,
∆t = చాప చివర భాగం కదలిన దూరం / వడి = 2/1 = 2 సె.
(చాప చివరి భాగం కదిలిన దూరం = 1మీ + 1మీ = 2 మీటర్లు)
న్యూటన్ రెండవ గమన నియమం నుండి

∆m అనేది ∆t సమయంలో వచ్చే ద్రవ్యరాశిలోని మార్పును సూచిస్తుంది. 2 సెకన్ల కాలంలో ద్రవ్యరాశిలో వచ్చే మార్పు మొత్తం చాప ద్రవ్యరాశికి సమానం.
F_net = (1 మీ/సె) X (1 కి.గ్రా) / 2 సె. = 1/2 న్యూటన్
క్షితిజ సమాంతర దిశలో ఒకే బలం పనిచేస్తుంది కనుక చాప చివర ప్రయోగించాల్ని బలం 1/2 న్యూటన్.

9th Class Physical Science Textbook Page No. 28

ప్రశ్న 3.
న్యూటన్ గమన నియమాలను అటవుడ్ ఒక ప్రయోగం ద్వారా నిరూపించాడు. పటంలో చూపినట్లు అటవుడ్ యంత్రంలో కప్పి ద్వారా పంపిన సాగే గుణం లేని ఒక తాడుకు రెండు చివరలలో m₁ మరియు m₂ ద్రవ్యరాశులు గల భారాలు వేలాడుతుంటాయి. (m₁ > m₂) అయిన, ఆ రెండు భారాల త్వరణాలను, తాడులో తన్యతను లెక్కించండి.

సాధన:
పటంలో చూపినట్లు తాడులో గల తన్యత ఎల్లప్పుడూ వస్తువులను పైకి లాగుతుంది.
m₁ ద్రవ్యరాశి యొక్క FBD ద్వారా ఆ ద్రవ్యరాశిపై తన్యత, (T) పై వైపుకు, దాని భారం (m₁ g) కిందవైపుకు పని చేస్తున్నాయని గ్రహించవచ్చు.

m₁ పై ఫలిత బలం,
F_net = m₁a
m₁g – T = m₁a ………….. (1)
m₁ పై ఫలిత బలం కలగజేసే త్వరణం ‘a’ m₁ కిందకి కదులుతుంటే m₂ పైకి వెళ్తుంది. కనుక వాటి త్వరణాల పరిమాణాలు సమానం.

m₂ యొక్క FBD పటం నుండి
F_net = T – m₂g = m₂a ……………. (2)
(1), (2) సమీకరణాలను సాధించగా

9th Class Physical Science Textbook Page No. 33

ప్రశ్న 4.
12000 కి.గ్రా. ద్రవ్యరాశి (m₁) గల ఫిరంగి నున్నని సమాంతర తలంపై ఉంది. అది 300 కి.గ్రా. ద్రవ్యరాశి (m₂) గల గుండును క్షితిజ సమాంతర దిశలో v₂ = 400 మీ./సె. వేగంతో విడుదల చేస్తే, ఆ ఫిరంగి వేగం (v₁) ఎంత?
సాధన:
ఫిరంగి ద్రవ్యరాశి (m₁) = 12000 కి.గ్రా
గుండు ద్రవ్యరాశి (m₂) = 300 కి.గ్రా
ఫిరంగి వేగము (v₁) = ?
గుండు వేగము (v₂) = 400 మీ./సె.
ఫిరంగి పేల్చిన తర్వాత దాని వేగం v₁ అనుకొనుము.
వ్యవస్థ తొలి ద్రవ్యవేగం శూన్యం.
వ్యవస్థ తుది ద్రవ్యవేగం = m₁v₁ + m₂v₂.
రేఖీయ ద్రవ్యవేగ నిత్యత్వ నియమము ప్రకారం
m₁v₁ + m₂v₂ = 0
m₁v₁ = – m₂v₂

ఫిరంగి పేలిన తర్వాత దాని వేగం = 10 మీ/సె.
ఫిరంగి వ్యతిరేక దిశలో కదులుతుంది.

పరికరాల జాబితా

చెక్క ట్రాక్, కాగితపు రింగు లేదా బంతి, పెన్నుమూత, గాజు గోళీ, సీసా, క్యారమ్ బోర్డు నమూనా, చెక్క దిమ్మలు, చెక్క స్కేలు, సాగే గుణం లేని తాడు, బెలూన్, స్ట్రా ముక్క, తాడు, రెండు కోడిగుడ్లు, మెత్తని దిండు, కప్పీ, రెండు స్ప్రింగ్ త్రాసులు, పరీక్ష నాళిక, రబ్బరు కార్కు, బున్సెన్ బర్నర్, దారము, స్టాండు, నీరు

9th Class Physical Science 2nd Lesson గమన నియమాలు Textbook Activities (కృత్యములు)

కృత్యం – 1

కాగితపు రింగుపై ఉంచిన పెన్ను మూత చలనాన్ని వివరించటం :

ప్రశ్న 1.
జడత్వాన్ని నిరూపించు ప్రయోగాన్ని తెల్పుము.

జవాబు:
ఉద్దేశ్యం : వస్తువు యొక్క జడత్వాన్ని నిరూపించుట.

కాగితపు రింగు కావలసిన పరికరాలు :
పెన్నుమూత, కాగితపు రింగు, వెడల్పు మూతిగల సీసా.

పద్ధతి :

1. ఒక దళసరి కాగితంతో రింగును తయారుచేయండి.
2. పటంలో చూపినట్లు ఒక సీసామూత మీద ఆ రింగును నిలబెట్టండి.
3. సీసామూతికి సరిగ్గా పైన పేపరు రింగుపై ఒక పెన్నుమూతను నిలబెట్టండి.
4. కాగితపు రింగును ఒక్కసారిగా వేగంగా మీ చేతితో లాగండి.
5. పెన్నుమూత, వెడల్పు మూతిగల సీసాలోనికి పడిపోతుంది.

వివరణ :
పై ప్రయోగాన్ని బట్టి మార్పును వ్యతిరేకించే లక్షణం పెన్నుమూత ప్రదర్శించినది కావున దానికి జడత్వ లక్షణం కలదని చెప్పవచ్చును.

కృత్యం – 2

స్టైకరుతో కొట్టిన కేరమ్ బోర్డు కాయిన్ చలనాన్ని పరిశీలించడం :

ప్రశ్న 2.
స్ట్రైకరుతో కొట్టిన కేరమ్ బోర్డు కాయిన్ చలనాన్ని పరిశీలించు ప్రయోగాన్ని వివరింపుము.
జవాబు:
ఉద్దేశ్యం :
స్ట్రైకరుతో కొట్టినపుడు కేరమ్ బోర్డు కాయిన్ చలనాన్ని పరిశీలించుట.

కావలసిన పరికరాలు :
క్యారమ్ బోర్డు, కాయిన్స్, స్టైకరు.

పద్ధతి :

1. క్యారమ్ బోర్డుపై కాయిన్లను ఒకే నిలువు వరుసలో నిలబెట్టండి.
2. కింది కాయినను స్ట్రైకర్ తో గట్టిగా కొట్టండి.
3. పటంలో చూపినట్లు కింది కాయిన్ మాత్రమే వరుస నుండి బయటకు వస్తుంది.
4. క్యారమ్ కాయిన్ల దొంతర నిలువుగా కిందకు దిగింది.

వివరణ :
పై ప్రయోగం ద్వారా వస్తువు పై పనిచేసే ఫలిత బలం శూన్యం అయినదని అర్ధమవుతుంది.

కృత్యం – 3

రెండు చెక్కపెట్టెలను ఒకే బలంతో నెట్టడం :

ప్రశ్న 3.
అధిక ద్రవ్యరాశి గల వస్తువు అధిక జడత్వాన్ని కలిగి ఉంటుందని చూపండి.
జవాబు:

1. రెండు వేరు వేరు ద్రవ్యరాశులు గల చెక్కదిమ్మెలను గచ్చుపై ఒక సరళరేఖపై ఉంచండి.
2. రెండు దిమ్మలను చెక్క స్కేలు సహాయంతో ఒకే బలంతో ముందుకు నెట్టండి.
3. తక్కువ ద్రవ్యరాశి గల చెక్కదిమ్మ ఎక్కువ త్వరణాన్ని పొంది ఎక్కువ దూరం వెళ్ళింది.
4. ఎక్కువ ద్రవ్యరాశి గల చెక్కదిమ్మ తక్కువ త్వరణాన్ని పొంది తక్కువ దూరం కదులుతుంది.
5. ఈ పరిశీలన వల్ల ఎక్కువ ద్రవ్యరాశి గల వస్తువు ఎక్కువ జడత్వాన్ని పొందుతాయని తెలుస్తుంది.

కృత్యం – 4

ప్రశ్న 4.
ఫలిత బలం – త్వరణం

నున్నగా ఉన్న తలం మీద ఒక మంచు ముక్క నుంచి నెమ్మదిగా నెట్టవలెను. అది వేగాన్ని ఎలా పుంజుకుంటుందో (ఎలా త్వరణాన్ని పొందుతుందో) గమనించవలెను. ఇప్పుడు ఫలిత బలాన్ని పెంచి, వేగంలో మార్పుని గమనించవలెను.
మంచు ముక్క త్వరణం పెరుగుతుంది.

కృత్యం – 5

ప్రశ్న 5.
ద్రవ్యరాశి – త్వరణం

ఒక మంచు ముక్కపై కొంత బలాన్ని ప్రయోగించినపుడు, అది త్వరణాన్ని పొందుతుంది. ఇప్పుడు ఎక్కువ ద్రవ్యరాశి గల మంచు ముక్కపై దాదాపు అంతే బలాన్ని ప్రయోగించి, త్వరణాన్ని పరిశీలించవలెను.

ఎక్కువ ద్రవ్యరాశి గల మంచుముక్క, తక్కువ ద్రవ్యరాశి గల మంచు ముక్క పొందిన త్వరణాన్ని పొందలేదు.

గమనించినది :
ద్రవ్యరాశి స్థిరంగా ఉన్నప్పుడు ఫలిత బలం ఎక్కువగా ఉంటే త్వరణం కూడా అధికంగా ఉంటుంది. అలాగే ఫలిత బలం స్థిరమైనప్పుడు ద్రవ్యరాశి ఎక్కువగా ఉంటే ఆ వస్తువుపై పొందిన త్వరణం తక్కువగా ఉంటుంది.

కృత్యం – 6

రెండు స్ప్రింగు త్రాసులను వ్యతిరేకదిశలో లాగటం :

ప్రశ్న 6.
రెండు స్ప్రింగ్ త్రాసుల ద్వారా న్యూటన్ మూడవ గమన సూత్రాన్ని ప్రయోగపూర్వకముగా నిరూపించుము.
(లేదా)
చర్య, ప్రతిచర్య బలాలు పరిమాణంలో సమానమని, దిశలో వ్యతిరేకమని నిరూపించు ప్రయోగమును తెల్పుము.
జవాబు:
ఉద్దేశ్యం : చర్య, ప్రతిచర్య బలాలను చూపుట.

కావలసిన పరికరాలు : రెండు స్ప్రింగు త్రాసులు, వాటి కొక్కెములు.

పద్ధతి :
వ్యతిరేక దిశలో పనిచేసే బలాలు

1. ఒకే విధమైన కొలతలుగల రెండు స్ప్రింగు త్రాసులు తీసుకోండి.
2. వాటి కొంకీలను పటంలో చూపినట్లు కలపండి.
3. ఇరువైపుల నుండి స్ప్రింగు త్రాసులు పట్టుకొని లాగండి.
4. అవి రెండూ సమాన రీడింగులను సూచిస్తాయి.
5. ఆ త్రాసులలోని స్ప్రింగులు ఒకదానిపై ఒకటి సమాన (F₁ = F₂) దిశలో, వ్యతిరేకంగా (F₁ = – F₂ ) బలాలు కలుగజేసుకుంటాయి.
6. ఈ రెండు వ్యతిరేక బలాల్ని కలిపి చర్య – ప్రతిచర్య బలాల జత అంటాము.

కృత్యం – 7

బెలూన్ రాకెట్:

ప్రశ్న 7.
బెలూన్ రాకెట్ ప్రయోగాన్ని న్యూటన్ మూడవ గమన నియమంతో ఏ విధముగా వివరించవచ్చును?
జవాబు:
ఉద్దేశ్యం :
బెలూన్ రాకెట్ ద్వారా న్యూటన్ మూడవ సూత్రాన్ని పరీక్షించుట.

పరికరాలు :
బెలూన్, దారము, స్ట్రా. టేపు.

పద్ధతి :

1. ఒక బెలూన్లోకి గాలి ఊది బయటికి వెళ్ళకుండా మూతిని గట్టిగా వేళ్ళతో పట్టుకోండి.
2. ఒక దారాన్ని స్ట్రా గుండా పంపండి.
3. పటంలో చూపిన విధంగా బెలూను స్టాకు టేపుతో అతికించండి.
4. దారం ఒక చివరి కొనను మీరు పట్టుకొని, రెండవ చివరను మీ స్నేహితుడిని పట్టుకోమనండి.
5. బెలూన్ మూతి వద్ద వేళ్ళను తీసివేయండి. మూతి ఉన్న దిశ ఎడమ దిశ అనుకొనుము.
6. బెలూన్లోని గాలి మూతి ద్వారా బయటికి కొంత వేగంతో, ఎడమవైపుకు వెళుతుంది.
7. బెలూన్ కుడి చేతి వైపుకు కదులుతుంది. దానికి అంటిపెట్టుకున్న స్ట్రా కూడా దానితోపాటు వెళు 190ది.

ఈ విధముగా చర్య (గాలి వెళ్ళడం), ప్రతిచర్య (బెలూన్ వెళ్ళడం) సమానముగా ఉండి, వాటి దిశలు వ్యతిరేకముగా కలవని తెలియుచున్నది.

ప్రయోగశాల కృత్యం

ప్రశ్న 8.
రెండు విభిన్న వస్తువుల మీద పనిచేయు చర్య, ప్రతిచర్య బలాలను ప్రయోగపూర్వకముగా చూపుము.
జవాబు:
ఉద్దేశ్యం :
రెండు విభిన్న వస్తువుల మీద పనిచేసే చర్య, ప్రతిచర్య బలాలను చూపుట.

కావలసిన పరికరాలు :
పరీక్షనాళిక, రబ్బరు కార్కు, బున్సెన్ బర్నర్, స్టాండు, దారం.

పద్ధతి :

1. ఒక పరీక్ష నాళికలో కొద్దిగా నీరు తీసుకొని దాని మూతిని రబ్బరు కార్కుతో మూయండి. –
2. పటంలో చూపిన విధంగా రెండు దారాల సహాయంతో పరీక్ష నాళికను క్షితిజ సమాంతరంగా వేలాడదీయండి.
3. బుస్సెన్ బర్నర్ సహాయంతో పరీక్ష నాళికను వేడి చేయండి.
4. వేడిచేయటం వలన పరీక్షనాళికలోని నీరు ఆవిరైపోతుంది.
5. ఆ ఆవిరి రబ్బరు కారును బయటకు నెట్టే వరకు పరీక్ష నాళికను వేడి చేస్తూనే ఉండాలి.
6. కార్కు బయటకు రావడం (చర్య), పరీక్ష నాళిక వెనుకకు జరగడం (ప్రతిచర్య) ఒక్కసారిగా గమనించవచ్చు.
7. కార్కు ద్రవ్యరాశి, పరీక్షనాళిక ద్రవ్యరాశి కన్నా తక్కువ కావడం వలన పరీక్షనాళిక కన్నా కార్కు ఎక్కువ వేగంతో ప్రయాణిస్తుంది.
   పై ప్రయోగం ద్వారా చర్య, ప్రతిచర్య బలాలను గమనించవచ్చును.

ప్రశ్న 9.
గ్రుడ్డును జారవిడవడం

రెండు కోడి గ్రుడ్లను తీసుకొని వాటిని ఒకే ఎత్తు నుండి, ఒకటి గట్టి గచ్చు మీద పడేటట్లుగా, రెండవది మెత్తని దిండు మీద పడేటట్లుగా వదలండి. తలాన్ని తాకిన తరువాత ఆ గ్రుడ్లలో గమనించిన మార్పులు వివరించుము.
జవాబు:

1. గట్టి గచ్చు మీద గ్రుడ్డు పగిలిపోతుంది కారణం, అధిక బలం అతిస్వల్ప కాలంలో పని చేయడమే.
2. మెత్తని దిండు మీద పడిన గ్రుడ్డు పగలదు కారణం, తక్కువ బలం ఎక్కువ కాలం పాటు పని చేసింది.

పై రెండు సందర్భాలలో గ్రుడ్డు పగులుతుందా, పగలదా అని నిర్ణయించేది గ్రుడు మీద పనిచేసే ఫలిత బలమే అని తెలుసుకున్నాను.

SCERT AP 7th Class English Government Textbook Answers 7th Lesson The Bond of Love Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 7 Questions and Answers The Bond of Love

7th Class English Unit 7 The The Bond of Love Textbook Questions and Answers

Look at the pictures and answer the questions that follow.

Question 1.
Identify and name the animals in the picture.
Answer:
The animals in the picture are a dog and a calf.

Question 2.
Do you have any pet animals?
Answer:
Yes, I have a dog.

Question 3.
Have you ever felt their love and affection? How?
Answer:
Yes, I have felt the love and affection of my pet dog. It always likes to sit near me. It always likes to come with me to school. It wags its tail on seeing me.

Question 4.
Do you think our pet animals too miss us when we are away? Discuss.
Answer:
Yes, they also miss our presence. When they see us after some gap, they rush to us and express their affectionate feelings.

Question 5.
How are the pet animals similar and different from the domestic animals?
Answer:
Domestic animals are the animals captured and tamed to live with humans for economic purposes. Pets, on the other hand, are the animals solely kept for companionship in the household.

Questions Given In The Lesson

Possible answers to the questions given in the middle of the lesson :

Question 1.
What tricks do you like to teach your pet?
Answer:
I like to teach my pet dog to bring the things to me, to jump over the walls, to catch the ball, to chase the animals, etc.

Question 2.
Do you really think the pet animals have love for one person in the family particularly?
Answer:
Yes, I really think the pet animals have love for the particular person who treats them kindly.

Question 3.
Have you ever seen such a bond between the pet animals and the member of the family? Share your experience with your friends.
Answer:
I have seen such a bond between the pet animals and family in many cases. In many families pet dogs show their love for their masters. For instance, our neighbours have a pet dog. The dog moves very closely with the master’s family. It feels very happy on seeing them. It wags its tail in a happy mood.

Reaping Comprehension

A. Answer the following questions.

Question 1.
“I got him for her by accident.”
i) Who says this?
ii) Whom does ‘him’ refer to? Whom does ‘her’ refer to?
iii) What is the incident referred to here?
Answer:
i) The author says this.
ii) ‘Him’ refers to the baby bear and ‘her’ refers to the author’s wife.
iii) The incident refers to the catching of the baby bear.

Question 2.
“He stood on his head in delight.”
i) Who does ‘he’ refer to?
ii) Why was he delighted?
Answer:
i) ‘He’ refers to the baby bear.
ii) ‘He’ was delighted to see the author’s wife after a long time.

Question 3.
“We all missed him greatly: but in a sense we were relieved.”
i) Who does ‘we all’ stand for?
ii) Who did they miss?
iii) Why did they feel relieved?
Answer:
i) The author, his wife and son.
ii) They missed the baby bear.
iii) They felt relieved because it was getting difficult to keep the baby bear at home.

Question 4.
What did Bruno eat in the library? What happened to him?
Answer:
Bruno entered the library and he ate some of the poison placed to kill the rats and mice. He could not stand on his feet. The veterinary doctor gave medicine. He gave three shots of injections. After thirty minutes, Bruno looked alright.

Question 5.
Do you think Bruno was a loving and playful pet? Why?
Answer:
Yes, Bruno was a loving and playful pet. But he was mischievous too. The bear became very attached to the narrator’s two Alsatian dogs and the children of the tenants.

Question 6.
How was the problem of keeping Bruno at home finally solved?
Answer:
The narrator and his wife made special arrangement for Bruno and created all facili¬ties for him. They prepared a special island for Bruno.

B. State whether the following statements are true or false.

1) Bruno was a loving and playful pet animal.
2) The zoo superintendent did not allow the narrator’s wife to take Bruno back home.
3) The ‘baby’ of Baba was a stump of wood.
4) The chemical that Bruno ate in the library was barium chloride.
5) Bruno was sent to Bangalore zoo.
Answer:

1. True
2. False
3. True
4. False
5. False

C. Read the following sentences and put them in the order of their occurrence in the story.

Statement	No.
His wife named the baby bear Bruno.
The narrator and his wife visited the zoo in Mysore.
The narrator brought a baby bear home.	1
Bruno ate rat poison and was treated by a vet
Bruno was sent to Mysore zoo.
The narrator and his wife pleaded with the zoo superintendent to give them back Bruno.
They started calling him Baba.
Bruno came back home and continued living with the narrator’s home on a special island.
Baba was overjoyed and stood on his head.
Both the narrator’s wife and Baba missed each other.

Answer:

Statement	No.
His wife named the baby bear Bruno.	2
The narrator and his wife visited the zoo in Mysore.	6
The narrator brought a baby bear home.	1
Bruno ate rat poison and was treated by a vet	3
Bruno was sent to Mysore zoo.	5
The narrator and his wife pleaded with the zoo superintendent to give them back Bruno.	8
They started calling him Baba.	4
Bruno came back home and continued living with the narrator’s home on a special island.	9
Baba was overjoyed and stood on his head.	10
Both the narrator’s wife and Baba missed each other.	7

Vocabulary

A. Dictionary Activities
1. Consult the dictionary and fill in the missing letters with ‘ei’ or ’ie\
1. Mischievous
2. Hyg _ _ ne
3. Ingred _ _ nts
4. F _ _ lds
5. Pr _ _ st
6. R _ _ gn
7. Pat _ _ nee
8. Sl _ _ gh
9. V _ _ n
10. W _ _ gh
Answer:

1. Mischievous
2. Hygiene
3. Ingredients
4. Fields
5. Priest
6. Reign
7. Patience
8. Sleight
9. Vein
10. Weigh

Note:
1. Achieve, believe, thief, pierce (In general ‘i’ occurs before ‘e’)
2. Ceiling, receive, conceive, deceive (After ‘c’, ‘e’ occurs before ‘i’)
3. Neighbour, weight (Based on the sound ‘AY’)

2. Spell Check: Put a tick ‘✓’ mark for the right one and ‘✗’ for the wrong one.

Words	Tick / Cross
1. ingredients	✓
2. forfeit	✓
3. decieve	✗
4. caffeine	✓
5. greif	✗

B. Collective Nouns

Read the following sentences from text.

Once home, a squad of coolies made an island for Baba.

In the above sentence, notice the words in bold letters, ‘squad’ is a collective noun which means a group of people having a particular task.

A collective noun refers to a group of things. For example, a herd of elephants, a pack of cards, a flock of birds, etc.

C. Refer to a dictionary and match the following nouns with their collective nouns. One is done for you.

Answer:

Note: The collective noun represents the whole group as a single noun, so it takes the singular verb.

Example : A herd of elephants is crossing the highway.

In this sentence, the noun ‘herd’ takes the singular verb ‘is crossing’ though there are many elephants. Here the word ‘herd’ is considered as a single unit.

Grammar

A. Adverb and its Placement
Read the sentences from the text.

I duly presented it to my wife.

In the sentence above the word ‘duly’ is used to confirm the action giving a ‘present’. Such words are called adverbs of confirmation or negation.

The words such as certainly, definitely, surely, indeed and undoubtedly used to confirm the action. So they are adverbs of confirmation.

The words such as never, no, not are adverbs of negation.

These words are usually placed between subject and main verb or auxiliary and main verbs.

Position of Adverbs
There are three positions of adverbs.

1. At the beginning
a) Tomorrow, we have a yoga class.
b) Surely, I’ll help you.

2. In the middle
a) He seldom makes a mistake.
b) We often go to temple.

3. At the end
a) Children played happily.
b) She danced gracefully.

4. Rewrite the sentences by placing the adverbs in the appropriate place. One is done for you.
Eg : Radhi never can walk fast.

Radhi can never walk fast:
1. They will visit the zoo certainly.
Answer:
They will certainly visit the zoo.

2. We go on a picnic usually.
Answer:
We usually go on a picnic.

3. You baked well the cake.
Answer:
You baked the cake well.

4. Your decisions are correct absolutely.
Answer:
Your decisions are absolutely correct.

5. Get quickly my bag.
Answer:
Get my bag quickly.

6. She was praised by all well.
Answer:
She was praised well by all.

7. We speak truth always.
Answer:
We always speak truth.

8. The boy harshly talked to his friend.
Answer:
The boy talked to his friend harshly.

9. He talks often to me.
Answer:
He often talks to me.

10. Seldom Reeta completes her work on time.
Answer:
Reeta seldom completes her work’on time. ‘

B. Voice

Read the following sentences from the text.
1) An island was made for Baba.
2) Baba ate everything.

Notice the ‘subjects’ and the ‘action words’ in the sentences above.

After studying the table, we can say that in sentence ‘1’ the subject is not doing the action ‘make’ and in sentence ‘2’ the subject is doing the action ‘eat’.

If the subject is the doer of the action, we say the sentence is in active voice and if the subject is not the doer of the action the sentence is in passive form.

So here sentence ‘1’ is in passive voice and ‘2’ in active.

Let’s see how imperative sentences are written in passive form.

The imperative sentences can be written in passive voice in the following way.
Active : Do it at once.
Passive : Let it be done at once.
Active : Open the door.
Passive : Let the door be opened.
Active : Do not beat the bench.
Passive : Let the bench not be beaten.

Change the following into passive voice.

1. Bring a glass of water. …………………………………….
2. Do not pick the paper. …………………………………….
3. Give him the book. …………………………………….
4. Do not write the questions. …………………………………….
5. Do not waste water. …………………………………….
6. Plant more saplings on either side of the road. …………………………………….
Answer:

1. Let a glass of water be brought.
2. Let the paper not be picked.
3. Let the book be given to him.
4. Let the questions not be written.
5. Let water not be wasted.
6. Let more saplings be planted on either side of the road.

Writing

A. Guided conversation

In the story ‘The Bond of Love’, you have read how the narrator’s wife pleaded with the zoo superintendent to give her Baba back. The conversation given below is incomplete. Sit in pairs and complete it.

Narrator’s wife : Hello, sir. I am here to request for a favour.
Superintendent : Hello, Madam! What can ________ ?
Narrator’s wife : Bruno is ________ . I ________ So, I want to take Bruno back home.
Superintendent : I’m sorry ma’am. I can not allow you to take him. You have left Bruno under ________ so, Bruno is now ________ . We can’t give him back.
Narrator’s wife : Sir, Bruno is not taking food. He is growing ________ So please allow ________
perintendent : Yes! Alright, Madam! Please write a letter and ________
Narrator’s wife : _________
Answer:
Narrator’s wife : Hello, sir. 1 am here to request for a favour.
Superintendent : Hello, Madam! What can I do for you?
Narrator’s wife : Bruno is missing us. I am missing him. So, I want to take Bruno back home.
Superintendent : I’m sorry ma’am. I can not allow you to take him. You have left Bruno under the government so, Bruno is now the property of the government. We can’t give him back.
Narrator’s wife : Sir, Bruno is not taking food. He is growing weak. So please allow us to take Bruno home.
Superintendent : Yes! Alright, Madam.! Please write a letter and take him to home.
Narrator’s wife : Thank you so much.

B. Pair work

Now write a conversation on your own, imagining that your friend and you are the narrator and his wife. The wife is pleading with him to take her to the zoo where Bruno is kept. See that you add proper punctuation, interjections like oh, ah, hurrah, etc. Remember to keep your sentences short.
Answer:
Wife : The curator wrote that Baba is fretting and refuses to eat food.
Narrator : Don’t worry, dear. It will take some more time to adjust.
Wife : I must see Baba. Either you take me by car or I will go myself by bus or train.
Narrator : OK. I will take you to the zoo.
Wife : Thank you. Let’s start today.
Narrator : I think Baba would not recognize you.
Wife : No, I hope he would surely recognize me.
Narrator : Let us take permission and visit the zoo.

Talking Time

Now, sit in groups of four and enact the conversation before the class with proper intonation.

Language Functions:

In the guided conversation under writing ‘A’, you can notice ‘I’m sorry’ and Yes! Alright’ tell us that one can easily decline or accept the requests in a polite manner. Here are some examples for you to make these language functions easy.

Accepting the request	Denying the request
Yes! Alright.	No, thank you.
Sure, thank you.	I’m sorry, I can’t allow…
That’s a good idea.	That sounds great, but I can’t…
Yes, let’s do it.	I’m honoured, but I…
Let’s go for it.	I like it, but I can’t do it now.
That would be nice…	It’s very kind of you, but…
Sounds great/ good.	Thanks a lot, but I can’t…

Listening

Listen to the story and answer the questions that follow by ticking the correct option.

Dolphins are extraordinarily intelligent animals. They display culture, affection, care and emotions like humans. They have several highly developed forms of communication. They have a “signature whistle” which allows other individuals to recognise them. Dolphins are unselfish animals. They are known to stay and help injured individuals, even helping them to the surface to breath. They also help other water animals. There are many instances of dolphins helping humans and even whales. Dolphins are social animals. They live in groups and co-operate with each other to get food and in raising the calves, their young ones. Dolphins are extremely playful and curious animals. They play-fight with each other and also play with seaweed. Do you know dolphins can jump as high as 20 feet out of the water!
Questions:
1. What do dolphins do to make them recognize the other dolphins?
a) wags the tail
b) signature whistles
c) jump up above water
Answer:
b) signature whistles

2. According to the passage dolphins are
a) intelligent and playful
b) intelligent and selfish
c) cruel
Answer:
a) intelligent and playful

3. There are instances of dolphins helping ______ and ______ .
a) birds and sharks
b) ships and boats
c) humans and whales
Answer:
c) humans and whales

4. What are the young ones of dolphins called?
a) cubs
b) calves
c) babies
Answer:
b) calves

5. How high can a dolphin jump out of water?
a) as high as 30 feet
b) as high as 5 feet
c) as high as 20 feet
Answer:
c) as high as 20 feet

Project

Visit your neighbourhood and know how many of your neighbours have pet animals at home.

Fill in the table given below

Answer:

As you visited your neighbours’ house, you might have observed their pet animals, their food habits, play things, and whom they are most attached to among the family members. You may grow interest to have a pet for yourself. If so, write a few tines about the animal you would want as pet and mention your reasons.
Answer:
We all know that pets are remarkable for their capacity to love. Animals bring a vast number of benefits to their human companions, improving every aspect of their owners’ lives; from their health to their optimism and outlook towards the future.

Of all the pet animals, 1 would like to have a dog as my pet animal. I think it can keep us in a good mood. It can be a good friend and gives us good company. It relieves us from stress. It watches the house and gives security.

Fun Time

Work in pairs and create your own cartoon character. Decide on the following.

1. Will your character be human or an animal?
Answer:
My character will be an animal.

2. What will the character look like?
Answer:
The character will look like a monkey.

3. What kind of character will it be-kind, clever, adventurous?
Answer:
The character will be clever.

4. Where does the character live?
Answer:
The character lives on the branches of trees.

5. What does the character do?
Answer:
The character is playful and mischievous.

6. What is the name of your character?
Answer:
The name of my character is a monkey.

The Bond of Love Summary

The Bond of Love is about the emotional bond which the author’s wife and her pet bear share between them. The author rescued the baby bear in an accident and gifted it to his wife. After that, they were bonding like he was their child and the author’s wife loves him a lot. We see that the family nourished him and helped him grow. As Bruno starts growing up, he bonded with everyone, from the children to the pet dogs. He had his own bed and would play around with the little-ones.all day.

However, in an accident, one day he ate poison which was to kill rats. After consum-ing poison, Bruno got paralysed and after proper treatment, they were able to save him. Soon, life became normal when in another incident; he drank up a whole gallon of old engine oil meant for termites. But, surprisingly, it did not affect Bruno. Thus, Bruno started growing in size but was equally sweet and playfyl. Upon growing, they changed his name to ‘Baba’ which meant ‘a small boy’ in the Hindi language. He picked up a few tricks growing up and entertained everyone. Nonetheless, his size was a problem and being an animal, he was a threat to the children.

Therefore, everyone except the wife was ready to send him to a zoo as he was not fit as a pet now. While she did not agree initially, she had to give in for everyone’s safety. After the official paperwork, he was ready for the Mysore Zoo. The wife missed him terribly and asked everyone to visit the zoo about his well-being. She learned that Baba was not eating well and remained sad all day. So, after three months, she decides to visit him herself. Although everyone told her that Baba would not recognize her, he surprised everyone by recognizing her in a jiffy.

After that, she petted and pampered him and spent a lot of time with him. However, she could not leave him so she decided to take him back. After the formalities, she finally brought him back home and made a special island for him with deep dry pit and his belongings. So, she finally reunited with Baba and spent her days petting him and making him sleep in her lap, sharing the true bond of love.

The Bond of Love About the Author

Kenneth Douglas Stewart Anderson (1910-1974) was an India- born British writer who wrote books about his adventures in the jungles of South India. He often went into the jungle alone and unarmed to meditate and enjoy the beauty of untouched nature. His famous works include ‘Jungles Long Ago’, ‘The Ti¬ger Roars’ and ‘Jungle Tales for Children’.

Meanings For Difficult Words

sloth bear : a bear (seen in Indian subcontinent)
panting (adj.) : breathless / out of breath
companions (n) : friends
fur (n) : the short, fine, soft hair seen on an animal’s body
creature (n) : a living thing
pitiful (adj) : pathetic
capture (v) : take into one’s possession or custody
scooted (v) : ran away
scruff(n) : the back of an animal’s neck
aerated water : gas mixed water (soda)
befall (v) : happen
vet (n) : a veterinary doctor.
disdainfully (adv) : in a way of showing pride
curator (n) : a person in charge of the zoo
inconsolable (adj.) : not able to be comforted
fretting (adj.) : worried
petted (v) : stroke or pat an animal affectionately
gnarled (v) : rugged twisted
hoisted (v) : raised by means of ropes or pulleys

Hachiko – A Symbol of Loyalty

Reading Comprehension

Answer the following questions.

Question 1.
Who was Hachiko?
Answer:
Hachiko was a Japanese dog remembered for its loyalty towards its master.

Question 2.
How was Hachiko when he arrived to the professor’s house?
Answer:
He was very weak when he arrived to the professor’s house

Question 3.
Where would Hachiko accompany the professor every day?
a) to the university
b) to the railway station
c) to the river
Answer:
b) to the railway station

Question 4.
What happened to the Professor one day?
Answer:
He died of cerebral hemorrhage on his way back home.

Question 5.
Where did Hachiko wait for the Professor? How long did he wait for his master?
Answer:
Hachiko waited for the Professor for almost ten years.

Question 6.
How did Japanese pay their tribute to Hachiko?
Answer:
The Japanese paid their tribute to Hachiko by building a bronze statue for Hachiko at the same railway station where he used to wait for his master.

Check Point

Hachiko – A Symbol of Loyalty Summary

Hachiko is one of the most famous dogs of all time, and surely the most famous dog in Japan inspiring many people all around the world.

Hachiko was a dog of Akita breed. It was born in November 1923. Ueno, a professor in agriculture department was the owner of this dog. The professor would take the train to his work and come back by evening. Hachiko would accompany the Professor to the station every morning and would come back to the station every evening to receive his master. Their routine continued for years. On 21 May 1925, the Professor did not return as he died of cerebral hemorrhage on his way back home. Hachiko waited for his master as usual, but he did not return from work. Hachiko would visit the railway station every morning and evening. He longed for his owner. Hachiko waited for his master for almost ten years and died. He was buried next to Professor Ueno. The story of Hachiko’s love and loyalty towards his master made the Japanese build a bronze statue for Hachiko at the same railway station where he used to wait for his master.

Meanings For Difficult Words

Akita (n) : a large breed of dog from Japan
cerebral hemorrhage (n) : bleeding in the brain
adorable (adj) : lovable

SCERT AP 7th Class English Textbook Answers 4th Lesson The Brave Little Bowman Textbook Questions and Answers.

AP State Syllabus 7th Class English Unit 4 Questions and Answers The Brave Little Bowman

7th Class English Unit 4 The Brave Little Bowman Textbook Questions and Answers

Look at the picture below and answer the questions that follow.

Question 1.
What are the men doing?
Answer:
The men are fighting.

Question 2.
What weapons are they using?
Answer:
The men are using maces (gadha) to fight.

Question 3.
Where do we see such fight scenes?
Answer:
We see such fight scenes in wars during the times of kings.

Question 4.
Can you name soma world famous personalities from any field?
Answer:
Yes, I can name some world famous personalities. For example, Virat Kohli from cricket, Kalam from science and technology, Narendra Modi from politics, P.V.Sindhu from tennis.

Question 5.
Is it their appearance/skill that makes them great personalities?
Answer:
It is their skill that makes them great.

Questions Given In The Lesson

Possible answers to the questions given in the middle of the lesson :

Question 1.
Do you know the success story of Sudha Chandran? Discuss.
Answer:
Yes, I know the success story of Sudha Chandran. She is an Indian film actor and a famous Bharatanatyam dancer. She overcame her disability of losing her right leg in an accident and danced again with great courage and determination.

Question 2.
Collect the names of such personalities and share with your friends.
Answer:
Albert Einstein, Stephen Hawking, George Washington, Helen Keller, Franklin D.Roosevelt, Ludwig Van Beethoven, Nik Vujicic, Rowan Atkinson, Walt Disney are some of the successful personalities with disabilities. They proved that their disability couldn’t stop them from achieving their goals.

Question 3.
Can the big man win the battle ? Substantiate your answer.
Answer:
I think the big man can’t win the battle as he is not a skilled warrior.

Question 4.
Will the little man support the big man?
Answer:
Yes, the little man will support the big man.

Reading Comprehension

A. Answer the following questions.

Question 1.
Why didn’t the little bowman go to the king and ask for a job in the army?
Answer:
The little bowman was afraid that the king would reject him as he was short and had a crooked back.

Question 2.
What did the little bowman tell the big man to do when he saw him digging ditches?
Answer:
The bowman approached him and said, “The days of your misery are over! You will immediately be recruited in the army because of your physique and you can then introduce me to them as your assistant. I will do the work that you will be given to do and we shall divide the pay between’us. This way both of us will be able to live comfortably.”

Question 3.
How did the big man introduce the little man to the king?
Answer:
The big man introduced the little man to the king as his assistant.

Question 4.
Did the big man kill the tiger and the wild elephant? Who killed them?
Answer:
No, the big man did not kill the tiger and the wild elephant. The little bowman killed them with his skill in archery.

Question 5.
If you were the big man, what would you do in the battlefield?
Answer:
If I were the big man, I would not leave the battlefield. As I knew the skill of the little bowman in archery, I would stay on the elephant and finish the battle.

Question 6.
Did the running away of the big man from the battlefield benefit the little man? How?
Answer:
The running away of the big man from the battlefield benefited the little man undoubtedly. The little man got a change to prove his skill and power. He was recognized by the king and received the much-deserved honour at last.

B. Put the following sentences in the order of events.

The big man and the little man joined the king’s army.
The little man told the big man to ask the king to let him join the army.
The little man saw a big strong man digging a ditch.
The big man slipped off the war elephant’s back and ran off into the city.
The little man killed the tiger and the wild elephant.
Answer:
The big man and the little man joined the king’s army. (3)
The little man told the big man to ask the king to let him join the army. (2)
The little man saw a big strong man digging a ditch. (1)
The big man slipped off the war elephant’s back and ran off into the city. (5)
The little man killed the tiger and the wild elephant. (4)

C. Say whether the following statements are True or False.

1. The little bowman introduced the big man as his assistant to the king.
2. The little man killed the tiger arid the wild elephant.
3. The big man asked the king to pay him five hundred pieces a month.
4. The little bowman led the elephant into the battle and won the battle.
5. The king made the little bowman the chief of his army and gave him rich gifts
Answer:

1. False
2. True
3. False
4. True
5. True

Correct the false statements and write them here.
1. The big man introduced the little bowman as his assistant to the king.
3. The king told the big man that he would give a thousand silver coins a month.

Vocabulary

A. Crossword Puzzle
Fill the puzzle using the clues given below.
Across
1. an archer
3. sudden uncontrollable fear or anxiety
5. unkind, severe
6. having knowledge or ability
2. a brave soldier
3. express warm approval or admiration .
4. bent or twisted out of shape
7. a narrow channel dug at the side of the road or field

Answer:

B. Observe how the past and past participle forms of the verbs are formed in set I and set II.

Note:
Verbs such as walk, ask, join, etc, which you find in set I are Regular Verbs.
Verbs such as take, drive, give, etc, which you find in set II are Irregular Verbs.
Pick out the verbs from the lesson, and write the V2 (past) and V3 (past participle) forms and place them under proper headings.

C. Find the ‘antonyms / opposites’ for the given words from the reading text.

1. unarmed
2. foolish
3. unskilled
4. relaxed
5. coward
6. separate
7. gentle
8. proud
9. straight
10. dismount

Antonyms:

1. unarmed × armed
2. foolish × wise
3. unskilled × skilled
4. relaxed × disturbed
5. coward × brave
6. separate × join
7. gentle × harsh
8. proud × humble
9. straight × crooked
10. dismount × mount

D. Fill in the blanks with the opposite of the word underlined.

1. Never speak harshly, always speak _________ .
2. Cruelty towards animals is a sin. We should show _________ to animals.
3. Everybody likes to be praised. Nobody likes to be _________ .
4. I am glad I got the job, but _________ on leaving my home town.
5. David told his timid young brother to be _________ .
Answer:

1. Never speak harshly, always speak kindly.
2. Cruelty towards animals is a sin. We should show kindness to animals.
3. Everybody likes to be praised. Nobody likes to be blamed.
4. I am glad I got the job, but sad on leaving my home town.
5. David told his timid ybimg brother to be brave.

Grammar

Read the following sentences from the reading text.

• The king will take both of us.
• We will go to the king and ask for a job.
• Will you come with me?

These sentences are in the simple future tense.
Pick out some more sentences which are in the simple future tense from the reading text and write them here. .
1. ___________
2. ___________
3. ___________
4. ___________
5. ___________
6. ___________
Answer:
1. I will do the work assigned to you and we will divide the pay equally.
2. Okay, 1 will go with you.
3. I will take the both of you and give a thousand silver coins a month.
4. We will serve you to the best of our abilities.
5. Will you do it?
6. I will kill the tiger.
7. I will sit behind you on the war elephant and shoot with my bow and arrow.
8. I will fight for the king.

You have already learnt the structure and usage of simple future tense. Now, do the following exercise.

A. Here is how Karim, John and Indu plan their summer holidays.

Fill the blanks with suitable form of verb given in brackets.

1. Hello, I am Karim. Every summer we _______ (go) to Chennai to visit my grandparents. But this summer, we _______ (not visit) them. We _______ (go) on a tour to Singapore. We _______ (do) a lot of shopping there. We _______ (visit) all the sight-seeing places in Singapore. We _______ (stay) there for ten days.
Answer:
Hello, I am Karim. Every summer we go to Chennai to visit my grandparent But this summer, we will not visit them. We will go on a tour to Singapore. We will d0 of shopping there. We will visit all the sight-seeing places in Singapore. We will stay there for ten days.

2. Hello, 1 am John. This summer ______ (go) camping with my classmates and we ______ (climb) up trees. We ______ (make) campfires and ______ (sleep) in tents. But it ______ (last) only for a week. Then, like every summer. I ______ (read) books and ______ (watch) TV at home.
Answer:
Hello, I am John. This summer I will go camping with my classmates and we will climb up trees. We will make campfires and will sleep in tents. But it will last only for a week. Then, like every summer I will read books and will watch TV at home.

3. Hi, I am Indu. Every summer we ______ (go) to my grandpa’s village. He has a lovely farm. This summer too, we ______ (go) there. I ______ (ride) a horse. I ______ (climb) trees and ______ (go) fishing and (pick) up flowers also. I ______ (feed) the lovely animals.
Answer:
Hi, 1 am Indu. Every summer we go to my grandpa’s village. He has a lovely farm. This summer too, we will go there. I will ride a horse. I will climb trees and will go fishing and pick up flowers also. I will feed the lovely animals.

B. Fill the blanks with the verb in simple future tense. (One is done for you)
Ex : He ______ (come) tomorrow.
A. He will come tomorrow. ‘

1. Karim ______ (travel) around Europe next year.
2. The exams ______ (be) in June.
3. The students ______ (finish) the English project in two days.
4. He ______ (call) me tomorrow afternoon.
5. I ______ (get) you something to drink.
Answer:
1. Karim will travel around Europe next year. .
2. The exams will be in June.
3. The students will finish the English project in two days.
4. He will call me tomorrow afternoon.
5. I will get you something to drink.

C. Write negative sentences for the given positive sentences. (One is done for you.)
Ex : They will go shopping on Saturday.
A. They will not go shopping on Saturday.

1. My mother will assign work to me.
Answer:
My mother will not assign work to me.

2. He will get the job.
Answer:
He will not get the job.

3. We shall buy another house.
Answer:
We shall not buy another house.

4. The doctor will see you very soon.
Answer:
The doctor will not see you very soon.

5. He will leave tomorrow.
Answer:
He will not leave tomorrow.

D. Framing questions that take Yes/No responses
Read the following sentences from the story.
Little Man : Can’t you find some other work?
Big Man : No, I can’t.
The King : Have you heard about the wild elephant?
Big Man : Yes, your Majesty.
The King : You must go to the forest and kill the tiger. Will you do it?
Big Man : Yes, your Majesty! I will kill the tiger.

Look at the answers to the above questions. Those answers begin with either YES or NO.

The above questions begin with words can, have, will, did etc. (The Auxiliary Verbs). Now let us see how these questions are framed.

1. Observe the position of the auxiliary verb in the statement and the question.

Statement	Question
1. She is learning classical dance.	Is she learning classical dance?
2. They were playing chess.	Were they playing chess?
3. He will finish the project in time.	Will he finish the project in time?
4. We can enjoy the movie.	Can we enjoy the movie?
5. I should write the examination.	Should I write the examination?

Now, frame questions to the given statements. (One is done for you)
1. He was a skilled archer.
Answer:
Was he a skilled archer?

2. The king will take both of them.
Answer:
Will the king take both of them?

3. I am not a skilled warrior.
Answer:
Am I not a skilled warrior?

4. She is preparing dinner for us.
Answer:
Is she preparing dinner for us?

5. The little girl can tell the names of all Indian Presidents.
Answer:
Can the little girl tell the names of all Indian Presidents?

6. My friends are going on an excursion.
Answer:
Are my friends going on an excursion?

7. They were building a house by this time last year.
Answer:
Were they building a house by this time last year?

8. I should attend the meeting.
Answer:
Should I attend the meeting?

9. We shall take up the challenge.
Answer:
Shall we take up the challenge?

10. The Prime Minister has declared the lockdown.
Answer:
Has the Prime Minister declared the lockdown?

2. Observe the following Statements and Questions.

Statement	Yes / No Question
Birds fly in the air.	Do birds fly in the air?
A cow gives us milk.	Does a cow give us milk?
He got top rank in the examination.	Did he get top rank in the examination?

Now, frame questions for the given statements: (One is done for you)

1. The rainbow appears in the sky.
Answer:
Does the rainbow appear in the sky?

2. The Sun rises in the east.
Answer:
Does the Sun rise in the east?

3. Trees give us fruits.
Answer:
Do trees give us fruits?

4. He wrote a novel.
Answer:
Did he write a novel?

5. She sang a song on the dais.
Answer:
Did she sing a song on the dais?

Writing

A. In the story the big man was appreciated for killing the tiger and the wild elephant. He started ignoring the little bowman. Describe the feelings of the little bowman in this context.

Make use of the following hints.

Unlucky I am – with my skill – killed the tiger – killed the wild elephant – but credit went to the big man – the king and the people praised him — I was ignored – really unfortunate – what can I do now? – can I reveal the truth — may the king punish us – better to keep quiet.
Answer:
How unlucky I am! I killed the tiger and the wild elephant with my skill. But the credit went to the big man. I did not get any recognition. The king and the people praised him but I was ignored. It is really unfortunate. What can I do now? Can I reveal the truth? The king may punish us if I reveal the truth. So it is better to keep quiet.

B. You have read the lesson ‘The Brave Little Bowman’. Rewrite it in the form a story.
Answer:
Once upon a time, there lived a bowman. He was a skillful archer in a city. Though he was short in height and had a crooked back, none could beat him in archery. One day he thought, “ I am good enough to join the king’s army, but he would never take me in because of my short stature and hunched back. I must look for someone tall and pow¬erful, and then I can enter the king’s army as his page.”

One day, the little bowman found the kind of man he was Iooking for. He was a tall and powerful man and used to dig ditches to earn his living. The bowman approached him and said, “The days of your misery are over! 1 am the best archer of this country and worthy of being a part of the king’s royal army. But, I may get rejected because of my height and crooked back. So, I need your help. You will immediately be recruited in the, army because of your physique and you can then introduce me to them as your assistant. I will do the work that you will be given to vdo and we shall divide the pay between us. This way both of us wili be able to live comfortably.”

The tall man gladly agreed. Together they reached the king’s palace and sent word to the king that a famous bowman was there to meet him. The king met the bowman and being impressed by his towering personality, joined him in the royal army. The little man’s dream had come true. He was now a part of the royal army, though disguised as the assistant of the big man.

In those days, there was a man-eater tiger on the loose in the jungle. The king sent for the big man and ordered him to kill the tiger. The big man told the little bowman what the king had said. They went to the forest together and soon, the little bowman shot the tiger dead. The king was extremely impressed by the heroic act of the big man and rewarded him with expensive gifts.

Some days, later, a wild elephant came on the city roads and started killing the people. The big man was asked to go and kill the elephant. The big man carried the little bowman on his shoulders and as always, the little bowman hit his target and killed the elephant.The king was full of praise for the big man and gave him a reward. The big man started treating the little man as his servant and spoke him Very rudely. The little bowmah was very sad.

A few days later, the king of the neighbouring country attacked the kingdom. The king at once sent his army. The big man was mounted on a majestic elephant and was wearing shining armour. The little bowman knew that the big man could not shoot, so he also took his bow and arrow and quietly sat behind the big man on the elephant.

When the big man saw a huge enemy army in front of him, he started to shake with fear. The little bowman asked him to keep sitting quietly, but the big man was so nervous that he jumped off the elephant and ran back to the city from the battle-field.

The little bowman led the elephant fearlessly into the battle-field and killed many of the enemies with his unmistakable shots. All the soldiers were motivated by the little man’s act of bravery and they soon forced the enemy army to withdraw, itself. The king now understood that it was the little bowman who was the real hero. He made ‘ him the chief of his army andalso rewarded him with rich gifts.

Talking Time

Language Function : Offering and asking for help:

Read the-following conversation between Gowtham and Sudha. Work in pairs.

Gowtham : Hello ! Sudha. What will you do tomorrow?
Sudha : I’ll work on my English project.
Gowtham : Shall I help you to complete your project work?
Sudha : I’ll be glad if you can.
Gowtham : Certainly, Sudha.
Sudha : Thank you very much.

Here are some examples for asking for help / offering help :

Asking for help	Offering help
Could you help me ………….. Would you mind ………….. Can you do me a small favour,.. Please ………….. Can you please lend me …………..	Can/May I help ………….. Would you like me to help you…. I will help you ………….. If you need any help, let me know…. Do you want me to help you …………..

Frame sentences to make offers using the words given and practice.
1) Cook the dinner (Shall) ___________________
2) Clean the floor (Can) ___________________
3) Cup of coffee (Would) ___________________
4) Do the shopping (Will) ___________________
5) Make some sandwiches (Would) ___________________
Answer:
Making Offers:

1. Shall I cook dinner for you?
2. Can I clean the floor?
3. Would you like me to give you a cup of coffee?
4. Would you like me to make some sandwiches for you?

Asking for Help:

1. Can you clean the floor for me?
2. Will you do’shopping for me?
3. Would you mind making some sandwiches for me?

Listening

Listen to the story and answer the questions that follow.

AN AUDACIOUS VILLAGE

Every country is protected by the armed forces like the army, the navy and the air force. If one wants to join the armed forces, one needs bravery and patriotism. You may have many professionals like engineers, doctors, lawyers, teachers, etc., in your locality. However it is rare to find people who work in the army from your area.

Madhavaram, called Military Madhavaram in West Godayari District, which is famous for sending men to serve in the armed services for centuries. Almost every household in the small village has at least one member serving in the armed forces.

During colonial rule, youth from the village flocked to the military and participated in major wars. Nearly 90 soldiers from this remote village participated in World War I and the figure rose up to 1,110 in World War II. Many soldiers from this village have laid down their lives.

Soldiers from the village have been a part of every war that independent India has fought. Many soldiers from this village sacrifice and guard the Indian frontiers. The girls in the village prefer to marry military men. The villagers, to commemorate the sacrifice and services of the soldiers, built a memorial for soldiers on the lines of New Delhi’s Amar Jawan. For many years, joining the Indian Armed Forces has remained the career of choice for the young men of the village.

Answer the following questions :
1. What qualities are required to join the Armed forces?
Answer:
Bravery and patriotism .

2. Whom do the girls in the village prefer to marry?
Answer:
Military men

3. How did the villagers commemorate the sacrifice made by the soldiers?
Answer:
By building memorials for soldiers on the lines of New Delhi’s Amar Jawan

4. How many World Wars are mentioned in the story?
Answer:
Two

5. What is Amar Jawan famous for?
Answer:
It is famous for building memorials for soldiers.

Study Skill

A. Study the following pie-chart and answer the questions that follow.

1. What is the pie chart about?
Answer:
The pie chart is about the recommended diet.

2. What is the percentage of vegetables in the diet recommended?
Answer:
18%

3. _______ occupied 9% of the diet recommended.
a) Vegetables
b) Grains
c) Other
Answer:
b) Grains

4. Which item occupies the highest percentage of our diet?
a) Protein
b) Fruit
c) Vegetables
(Note : The question is wrongly given in textbook. Hence, it has been changed for the convenience of students.)
Answer:
b) Fruit

5. Identify the true/false statement.
a) The percentage of fruit in our diet is 23%. (false)
b) Grains occupy the least perccentage of our diet. (false)
c) Vegetables occupy 18% share of our diet. (true)

B. Dictionary Entry

Fun Time

Look at the word ‘make’. By replacing the underlined letter ‘k’ in the word with r, l and t we can make new words like ‘mare, male, mate’ and so on. Now make at least three new words by replacing the letter underlined with any letter of your choice.
make – mare male mate
1) same – _______
2) poke – _______
3) robe – _______
4) sail – _______
5) bake – _______
Answer:

1. safe, sage, sake, sale, same, sane, sate, save
2. pole, pone, pope, pore, pose
3. rode, role, Rome, rope, rose, rote, rove
4. bail, fail, hail, jail, mail, nail, pail, rail,.sail, tail, vail, wail
5. babe, bade, bale, bane, bare, base

Riddles:

Here are some riddles for you to solve. (One is done for you.)
Ex. I am tall when I am young and 1 am short when I am old. What am I?
A. Candle

1) You walk into a room that contains a candle, a kerosene lamp, a match and a fireplace. What would you light first?
2) A man dies of old age on his 25th birthday. How is this possible?
3) What has many keys but can’t open, a single lock?
4) What is black when it is clean and white when it is dirty?
5) Where does today come before yesterday?
Answer:
1) A match
2) The man’s birthday falls on February 29.
(Or)
The man was born on February 29.
3) A piano
4) A blackboard
5) In the dictionary entries

Tongue Twisters:

Say them aloud.

1. Troubles never troubled Trouble, as he himself troubled troubles.
   Mine collected fine and wished to have wine but the shopkeeper closed at nine for fear of fine.
   Bumble often mumbles something to Rumble but the latter does not catch the matter as nothing matters to him.
   Mr. Will, prepared a will as he willed to inherit his paper mill to his daughter, Jill.
   Ms. Sind wound the bandage round the wound and soon unwound it as it was not wound properly around the wound.

The Brave Little Bowman Summary

Once upon a time, there lived a skillful archer in a city. Though he was short in ‘ height and had a crooked back, none could beat him in archery. One day he thought, “I am good enough to join the king’s army, but he would never take ine in because of my short stature and hunched back. I must look for someone tall and powerful, and then I can enter the king’s army as his .page.”

One day, the little bowman found the kind of man he was looking for. He “was a tall and powerful man and used to dig ditches to earn his living. The bowman approached him and said, “The days of your misery are over! I am the best archer of this country and worthy of being a part of the king’s royal army. But, I may get rejected because of my height and crooked back. So, 1 need your help. You will immediately be recruited in the army because of your physique and you can then introduce me to them as your assistant. I will do the work that you will be given to do and we shall divide the pay between us. This way both of us will be able to live comfortably.”

The tall man gladly agreed. Together-they reached the king’s palace and sent word to the king that a famous bowman was there to meet him. The, king met the bowman and being impressed by his towering personality, joined him in the royal army. The little man’s dream had come true. He was now a part of the royal army, though disguised as the assistant of the big man.

In those days, there was a man-eater tiger on the loose in the jungle. The king sent for the big man and ordered him to kill the tiger. The big man told the little bowman what the king had said. They went to the forest together and soon, the little bowman shot the tiger dead. The king was extremely impressed by the heroic act of the big man and rewarded him with expensive gifts.

Some days, later, a wild elephant came on the city roads and started killing the people. The big man was asked to go and kill the elephant. The big man carried the little bowman on his shoulders and as always, the little bowman hit his target and killed the elephant. The king was full of praise for the big man and gave him a reward. The big man started treating the little man as his servant and spoke him very rudely. The little bowman was very sad.

A few days later, the king of the neighbouring country attacked the kingdom. The king at once &ent his army. The big man was mounted on a majestic elephant and was wearing shining armour. The little bowman knew that the big man could not shoot, so he also took his bow and arrow and quietly sat behind the big man on the elephant.

When the big man saw a huge enemy army in front of him, he started to shake with fear. The little bowman asked him to keep sitting quietly, but the big man was so nervous that he jumped off the elephant and ran back to the city from the battle-field.

The little bowman led the elephant fearlessly into the battle-field and killed many of the enemies with his unmistakable shots. All the soldiers were motivated by the little man’s act of bravery and they soon forced the enemy army to withdraw itself. The king now understood that it was the little bowman who was the read hero. He made him the chief of his army and also rewarded him with rich gifts.

Meanings For Difficult Worps

crooked (adj) : bent,or twisted out of shape
ditch (n) : a narrow channel dug at the side of the road or field, to carry away water
earn a living (idiom) : to earn money needed for food and clothing
praise (v) : express warm approval or admiration
harsh (adj) : unkind, severe
bowman (n) : an archer
Your Majesty! (phrase) : the title used to speak to a king (Respected great king)
Your Highness! (phrase) : the title used to speak to a king (Respected great king)
mounted (adj) : riding an animal, typically a horse
warrior (n) : a brave or experienced soldier or fighter
skilled (adj) : having or showing the knowledge or ability
panic (n) : sudden uncontrollable fear or anxiety
put fear to rest (phrase) : to calm one’s fear
gave a cold shoulder (phrase) : tread in an unfriendly way
a bolt from the blue (phrase) : a sudden unexpected news
armed (adj) : carrying weapons to fight

A Fairy Song Poem

Over hill, over dale,
Thorough bush, thorough brier,
Over park, over pale,
Thorough flood, thorough fire !
I do wander everywhere,
Swifter than the moon’s sphere;
And I serve the Fairy Queen,
To dew her orbs upon the green;
The cowslips tall her pensioners be;
In their gold coats spots you see;
Those be rubies, fairy favours;
In those freckles live their savours;
I must go seek some dewdrops here,
And hang a pearl in every cowslip’s ear. -By William Shakespeare

Appreciation of the Poem

A. Choose the correct options to complete the sentences.

1. The fairy wanders _________
a) over the dale
b) over the hill
c) everywhere
Answer:
c) everywhere

2. The fairy is serving the Fairy Queen by dropping upon the green.
a) dewdrops
b) cowslips
c) rubies
Answer:
a) dewdrops

3. The fairy walks faster than the rotation of the
a) Fairy Queen
b) dewdrops
c) Moon
Answer:
c) Moon

4. The fairy wants to hang a in every cowslip’s ear.
a) dewdrops
b) ruby
c) pearl
Answer:
c) pearl

5. Who are the fairy queen’s pensioners?
a) cowslips
b) dew drops
c) orbs
Answer:
a) cowslips

B. Answer the following questions :

1. Where does the fairy wander?
Answer:
The fairy wanders over hills, dales, parks and pales and through bushes, briers, floods and fire.

2. How quickly does the fairy wander?
Answer:
He wanders faster than the moon.

3. Who does the fairy serve?
Answer:
The fairy serves the Fairy Queen.

4. What are the spots on the cowslips compared with ?
Answer:
The sports on the cowslips are compared with rubies.

5. Identify and write the other rhyming words in the poem:.
( E.g. dale – pale)
Answer:
brier – fire where – sphere
queen – green be – see
favours – savours here- ear

Check Point

A Fairy Song Summary

The poem ‘A Fairy Song’, refers to a fairy that serves his/her fairy queen. He/She spreads the dew on the flower everywhere he/she crosses. He/She wanders many places to do this work like hills, pales and so on.

The fairy flies over hill and open river valleys, through bushes and prickly plants, above parks and fences, through floods and fire.

The fairy travels everywhere faster than the moon revolves around the earth. The fairy serves the Fairy Queen.

The fairy works for the fairy queen and must deliver dewdrops (orbs here refers to the spherical shape of the drops) on the greenery around. This includes delivering dewdrops to the cowslips – a yellow flower with tall slender stems. The cowslips are therefore indebted to the fairy queen and therefore become her pensioners.

In their yellow gold petals being referred to as coats… thus personifying it in a way, you can see spots. The spots are red in colour and therefore look like rubies. If you have seen a cowslip, you will notice it has red spots in the centre. The poet says this is possible because of the favour the fairy does to the cowslips by delivering dew to them. The red spots are compared to freckles that appear at the peak of a cowslip’s life.

The fairy finally says that he/she must look for more dewdrops that have been compared to pearls so that he/she can hang them in every cowslip’s ear. Again this is a personification where the cowslip is given a human quality of having an ear that can be fashioned with a pearl.

A Fairy Song About the Poet

William Shakespeare (1564 – 1616) was an English playwright, poet, and actor often called the English National Poet and consid¬ered by many to be the greatest dramatist of all time. He was nicknamed The Bard of Avon. Shakespeare’s works include 38 plays, 2 narrative poems, and 154 sonnets and a variety of other poems. His plays like Hamlet, Macbeth, King Lear are some of the finest works in those genres. Some of his works are studied as academic subjects at postgraduate level across the world. This poem (A Fairy Song) is

Meanings For Difficult Words

dale (n) : an open river valley (in a hilly area)
thorough (prep.) : old spelling of ‘through’
brier (n) : tangled mass of prickly plants / a thorny plant
pale (n) : a wooden strip forming part of a fence
wander (v) : move about aimlessly or without any destination, often in search of food or employment
swifter (adj) : faster
sphere (n) : range / ball / area
to dew her orbs (phr.) : In this poem, dew has been used as a verb which could mean to place ‘tiny drops (orbs) of water that form on cool surfaces at night, when atmospheric vapor condenses’
cowslips (n) : The cowslip is a yellow flower belonging to the primrose family. Its name comes from old English for cow dung, perhaps because the plant commonly grew amongst the manure in cow pastures.
pensioners (n) : followers/dependants
rubies (n) : red gemstones
favours (v) : to treat somebody better than you treat other people
freckles (n) : a small brownish spots (of the pigment melanin) on the skin
savours (v) : get enjoyment from; take pleasure in
dewdrops (n) : drops of dew

Language Devices in the Poem :
Hyperbole : Line 4 & Line 6
→ Thorough flood, thorough fire!
→ Swifter than the moon’s sphere

Personification : Line 14
And hang a pearl in every cowslip’s ear
Simile : Line 6

The writer uses connective word ‘than’ in this line. The poet is comparing ‘swifter’ to the moon’s sphere.
→ Swifter than the moon’s sphere

AP State Syllabus AP Board 9th Class Physical Science Important Questions Chapter 9 Floating Bodies

AP State Syllabus 9th Class Physical Science Important Questions 9th Lesson Floating Bodies

9th Class Physical Science 9th Lesson Floating Bodies 1 Mark Important Questions and Answers

Question 1.
Scientifically what is density?
Answer:
Density is defined as mass per unit volume.

Question 2.
Define relative density.
Answer:
Relative density is the ratio of density of an object to the density of water.

Question 3.
What instrument is used to determine the purity of milk?
Answer:
Purity of milk can be determined by using lactometer.

Question 4.
What instrument is used to know the relative density of liquids?
Answer:
Relative density of liquids can be determined by using hydrometer.

Question 5.
What is atmospheric pressure?
Answer:
Air in our surroundings exerts pressure on the surface of earth called atmospheric pressure.
Atmospheric pressure P₀ = ρhg

Question 6.
State Archimedes’ principle.
Answer:
Archimedes’ principle states that when a body is immersed in a fluid it experiences an upward force of buoyancy equal to the weight of fluid displaced by the immersed portion of the body.

Question 7.
State Pascal’s principle.
Answer:
Pascal’s principle states that external pressure applied to an enclosed body of fluid is transmitted equally in all directions throughout the fluid.

Question 8.
What is the principle involved in working of hydraulic lift?
Hydraulic lift works using Pascal’s law.

Question 9.
In what direction does the buoyant force on an object immersed in a liquid act?
Answer:
Buoyant force on an object acts upward direction.

9th Class Physical Science 8th Lesson Gravitation 2 Marks Important Questions and Answers

Question 1.
Define density and give its units.
Answer:
Density is defined as the mass per unit volume.

Units : Unit for density is gm/cm³ (or) kg/m³.

Question 2.
Define relative density and give its units.
Answer:
Relative density is the ratio of density of an object to the density of water.

Units : Relative density has no units.

Question 3.
Why does the wooden block float on water even though it is heavier than a marble?
Answer:
The relative density of wooden block is less than the relative density of water whereas relative density of marble (glass) is more than that of water. Hence wooden block floats on water and marble sinks in water.

Question 4.
What do we mean by ‘heavy’, what do we mean by ‘light’?
Answer:
‘Heavy’ and ‘light’ can be decided based on the density of the object. Among the objects of equal volume, the one which weighs more can be treated as ‘heavy’ and the other one can be treated as ‘light’.

Question 5.
Relative density of silver is 10.8. What is density of silver in S.I. unit?
Answer:
Relative density of silver = 10.8

Density of water in S.I. system = 0³ kg/m³.
Density of silver = Relative density × Density of water = 10.8 × 10³ kg/m³.

Question 6.
Why does a block of plastic released under come up to the surface of water?
Answer:
Density of plastic is less than water. As the density of water is more than plastic, water exerts upward force which is known as buoyant force. So, the block of plastic come up to the surface of water.

Question 7.
The volume of 50 g. of a substance is 20 cm³. If the density of water is 1 g/cm³, will the substance float or sink?
Answer:

The density of substance is more than water so the substance sinks in the water.

Question 8.
An iron nail sinks in water. While a large ship floats on the surface of water. Give reason.
Answer:
The weight of water displaced by iron needle is less than its own weight, so it sinks. On the other hand, the ship displaces water more than its own weight, so it floats on water.

Question 9.
The density of gold is 19 g/cm³. Find the volume of 95 g of fold.
Answer:

Question 10.
A floating boat displaces water weighing 6000 newtons.
a) What is the buoyant force on the boat?
b) What is the weight of the boat?
Answer:
a) By Archimedes’ principles, the buoyant force acting on the object by it.
So, the buoyant force on the boat = 6000 newtons.

b) According to the principle of floating
Weight of object = Weight of liquid displaced by it
⇒ Weight of the boat = 6000 newtons

Question 11.
The volume of 50 g. of a substance is 20 cm . If the density of water is 1 g cm^-3, will the substance float or sink?
Answer:

2. Density of water = 1 g cm^-3.
As the density of substance is greater than that of water, so, the substance will sink in water.

Question 12.
Write any two differences between density and relative density.
Answer:

9th Class Physical Science 8th Lesson Gravitation 4 Marks Important Questions and Answers

Question 1.
Derive an expression for atmospheric pressure.
Answer:
1) All objects on the surface of the earth are subject to constant atmospheric pressure.

2) We know that the pressure is thrust (force) per unit area.

Question 2.
How can you measure the atmospheric pressure?
Answer:
1) Atmospheric pressure can be calculated with the help of the height of mercury column.

2) The weight of the mercury column in the tube is equal to the force applied on it by the mercury in the bowl due to atmospheric pressure.
∴ Weight of mercury column (W)
= Mass of mercury (m) × g
= Volume × density × g
= Cross sectional area of the tube × height of the tube × density × g
= Ahρg

Let P₀ be the atmospheric pressure.
Force on the column due to atmospheric pressure = P₀ A
Then Ahρg = P₀ A ⇒ P₀ = hρg
Here ‘ρ’ and ‘g’ are constants. So the height of mercury column depends on the atmospheric pressure.
We know height of mercury column h = 76 cm = 76 × 10^-2 m
Density of mercury (ρ) = 13.6 gm/cc = 13.6 × 10³ kg/m³3
Acceleration due to gravity (g) = 9.8 m/sec2
P₀ = hρg = 76 × 10^-2 × 13.6 × 10³ × 9.8 = 1.01 × 10⁵ kg m/m²s²
1 kg m\sec² = 1 Newton
P₀ = 1.01 × 10⁵ N/m²
This value is called atmospheric pressure.
1 Atmosphere = 1.01 × 10⁵ N/m² = 1.01 × 10⁵ Pascal

Question 3.
Calculate the pressure at a depth ‘h’ in a liquid.
Answer:

1) Let us consider a container which contains a liquid in it of density ‘ p

2) Consider cylindrical column of height ‘h’ from the surface of the liquid of cross sectional area “A”.

3) The volume of the liquid column V = Ah
Mass = Volume x density
⇒ m = Ahρ
Weight W = mg = Ahρg
From Newton’s law the net force on the liquid column is zero, because it is at rest.

4) The forces acting on the water column are
a) Weight (W), vertically down
b) Force on top surface due to atmospheric pressure (P₀ A) acting vertically down.
c) Force on the bottom surface of the column due to static pressure of liquid (PA), acting vertically up.

5) From Newton’s law we get

PA = P₀A + W ⇒ PA = P₀A + hρgA =⇒ PA = A (P₀ + hρg)
∴ P = P₀ + hρg
P = Pressure at depth h’ from the surface of the liquid
P₀ = Atmospheric pressure
∴ The pressure inside the liquid at a constant depth is constant.

Question 4.
Calculate the pressure difference at different levels of depth in fluids.
Answer:

1) Let us consider a cylindrical column of liquid of height ‘h’ with cross sectional area
‘A’ and let ‘P’ be the density of the liquid.

2) The pressure P₁ in the liquid at depth h, is
P₁ = P₀ + h₁ρg ………(1)

3) Similarly pressure P₂ in the liquid at depth h₂ is
P₂ = P₀ + h₂ρg …………..(2)

4) From (1) and (2), P₂ – P₁ = h₂ρg – h₁pg
P₂ – p₁ = ρg (h₂ – h₁)

5) From the figure h₂ – h₁ = h
∴ P₂ – p₁ = hρg

6) The pressure difference between two levels in that liquid = hρg

7) Here ρ and g are constants, so the pressure difference increases with an increase in depth.

Question 5.
State Pascal’s principle and explain it with an example.
(OR)
Write Pascal’s law. Draw the diagram of any device works based as Pascals’ law.
Answer:
Pascal’s principle :
Pascal’s principle states that external pressure applied to a enclosed body of fluid is transmitted equally in all directions throughout the fluid volume and the walls of the containing vessel.

Explanation :

1. Look at the figure.
2. Here we have an enclosed volume of fluid in a U-shaped tube.
3. The fluid is enclosed in the tube by two leak-proof pistons in each arm.
4. The ratio of cross-section areas of the right and left tubes is A₂ : A₁ and A₂ > A₁
5. When a force F₁ is applied to the left piston, the excess pressure acting on the fluid volume is F₁/A₁.
6. According to Pascal’s principle, this excess pressure is transmitted equally throughout the fluid volume.
7. The excess pressure in the right-side tube (Area A₂) is also F₁/A₁ and since its area is A₂, the upward force acting on the right piston is F₂ = A₂ × F₁/A₁, which is much larger in magnitude than F₁
8. Thus the application of Pascal’s principle results in a large upward force on the right piston when a small downward force is applied on the left piston.

Question 6.
The volume of a solid of mass 500g is 350 cm³.
a) What will be the density of this solid?
b) What will be the relative density of the solid?
c) Will it float or sink in water?
Answer:

c) Relative density of solid is greater than the relative density of water. So, it will sink in water.