Category: Class 9

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 2 The Natural Realms.

AP State Syllabus 9th Class Social Studies Important Questions 2nd Lesson The Natural Realms

9th Class Social 2nd Lesson The Natural Realms 1 Mark Important Questions and Answers

Question 1.
Write any two landforms which are formed by work of water? (SA-II : 2016 – 17)
Answer:
V-shaped valley. Deltas etc.

Question 2.
Give any one reason for the following. (SA-I : 2019 – 20)
Answer:
The majority of Earth’s volcanoes and earthquakes take place along the pacific basin. A. Plate boundaries are found all the way around the pacific basin.

9th Class Social 2nd Lesson The Natural Realms 2 Marks Important Questions and Answers

Question 1.
What are the effects of movements of tectonic plates. (SA-III : 2015 – 16)
Answer:

• The movement of these plates have changed the position and size of the continents over millions of years.
• These movements influenced the evaluation of the present land form features of India.
• The movement of plates form a chain of mountains.
• This process causes earthquakes etc.

Question 2.
Arrange the following concept in a correct manner in the given table. (SA-II : 2017 – 18)
Concept: Mushroom rock, Sea arches, plunge pool, U shaped valley.

Answer:

Question 3.
With reference to the Third Order Landforms, answer the following questions : (SA-I : 2019 – 20)
a) What are ‘Third Order Landforms’?
Answer:
The shaping of the landforms by wind and water are called ‘Third Order Landforms’.

b) What are the factors that cause their formation?
Answer:
Water, wind, glaciers and waves.

9th Class Social 2nd Lesson The Natural Realms 4 Marks Important Questions and Answers

Question 1.
Explain how air and water transform the surface of the Earth? (SA-II : 2018 – 19)
Answer:
The Air and water transform the surface of the earth by the four activities.
These are:
Weathering :
Water and moisture in the air also help this process. Water reacts with the chemicals of the rocks and further weakens the rock. These processes by which the rocks are weakened and broken are called “Weathering”.

Erosion :
Flowing water and wind have great power and can slowly wear away or cut away the rocks and soil cover in higher places. Water acts in many ways, as rain, river, flowing ground water, sea waves, glaciers etc. Wind too takes many forms like storms, gusts etc.

The active wearing away of the earth’s surface by these moving agents is called erosion.

Transportation :
The eroded material in the form of small rocks, gravel, mud fine soil etc. carried by winds and water is called transportation.

Deposition :
When the rivers and winds slow down, they do not have the force to carry the material any more and they dump them. This dumped debris help to form plains and river basins.

9th Class Social 2nd Lesson The Natural Realms Important Questions and Answers

Question 1.
What are the natural realms of the Earth? Describe them.
Answer:
There are four natural realms of the earth. They are

1. Lithosphere
2. Hydrosphere
3. Atmosphere
4. Biosphere.

1. Lithosphere:
The hard top part of the earth, the solid crust, which is made up of rocks and minerals and covered with a thick layer of soil. Soil is called lithosphere. It has high mountains, plateaus, plains, deep valleys and oceans. We and most other living beings live on this realm.

2. Hydrosphere :
The realm of water is called hydrosphere. It comprises various sources of water and different types of water bodies like rivers, lakes, seas, oceans, etc. and in the atmosphere in the form of water vapour and clouds. Life on earth is not possible without water.

3. Atmosphere :
The thin layer of air that surrounds the earth is atmosphere. It consists of a large number of gases including oxygen, nitrogen, carbon dioxide, water vapour, etc. and also dust particles. This cover of air is held around the earth by its gravitational force and rotates around the sun with the Earth.

4. Biosphere :
The realm of life including bacteria which live high on atmosphere or in deep oceans constitutes the biosphere. Life needs the presence of all the three realms, land, water and air. So life resides in the intersection of the three natural realms. Life also actively changes the three other realms.

Question 2.
What are called plates? How many plates are there on the earth?
Answer:
The massive base of rocks on which all the continents and even the oceans are actually situated are called plates. There are six major plates and several minor ones on the Earth. The African, North American, South American, Indo-Australian, Antarctic, Eurasian, and Pacific are the major plates. Nazca and Arabian are some among the minor plates.

Question 3.
What are plate tectonics? How are they caused?
Answer:

1. The plates actually float on the mantle.
2. They are constantly being pushed and therefore keep moving slowly.
3. As a result of this movement, one plate pushes another neighbouring plate.
4. One plate is pushed under into the mantle while the other plate is pushed up to form a chain of mountains.
5. This movement of plates is called plate tectonics.
6. Plate tectonics cause earthquakes.

Question 4.
What is called sea-floor spreading? How does it occur?
Answer:
The eruptions on the mid-ocean ridge create new ocean floor made of basalt rocks, which then spread literally from the ridge and this newest crust slowly pushes the plate away from the ridge, which is called ‘sea-floor spreading’.

Question 5.
How is the river deposition useful to man?
Answer:

1. As water in a river flows down a slope, it plucks sediment from the land. Other streams join it forming a broad river basin.
2. The water carries soil, sand and sediments down stream.
3. As the river reaches flatter ground, it slows down and drops the sediments there. This is called deposition.
4. The sediments build up a flood plain.
5. At the river’s mouth, the water loses its force, drops all its sediments and thus deltas are formed.
6. Flood plains and deltas make fertile farm land.
7. The sediments deposited in flood plains and deltas are called silt.
8. Silt is rich in nutrients.
9. Many ancient civilisations flourished in flood plains and deltas.

Thus the deposition of rivers are useful to man.

Question 6.
What are the landforms originated by the wind action?
Answer:
Strong winds carry sand and fine soil which strike the hard rocks. These too act as abrasive sand paper and erode the hard rocks. The wind action creates a number of interesting erosional and depositional features in the desert.

1. Sand Dunes :
Due to weathering and persistent wind action there is a large accumulation of fine sand in many deserts. These form ‘sand dunes’.

2. Mushroom Rock :
Winds erode the lower section of the rocks more than the upper part. Therefore such rocks have narrower bottom and wider top like mushrooms. So they are called mushroom rocks.

3. Inselberg:
The isolated residual hills rising abruptly from the ground are called inselberg or Island Mountain. They are characterized by their very steep slopes and rather rounded tops.

4. Loess Plains :
a) The fine dust, which is fertile and yellow in colour, is blown beyond the deserts and is deposited on neighbouring land. This soil is called Loess. Loess are in fact fine loam, rich in lime and extremely porous.
b) The plains formed by deposition of loess are called Loess Plains.

Question 7.
Name the landforms due to the Glacier action.
Answer:
1. Slow moving of mass of ice (a river of ice) is called Glacier.
2. A Glacier erodes through a process called “Plucking” in which it lifts pieces of rock and transports them.
3. The landforms created due to Glacier’s action are :
a) U shaped Valley:
Through the dual process of plucking and abrasion, glaciers create a “U shaped Valley”.

b) Moraines :
Pebbles, cobbles, sand etc., may be deposited at various parts of the
glaciers. The deposition of this till is called moraines. –

c) Huge rugged boulders:
The huge rocks, which cannot be carried by, are left behind in the form of huge rugged boulders.

d) Ozone :
Ozone is an inorganic molecule with the chemical formula 03. It is a pale blue gas with a distinctively pungent smell. Ozone’s 03 formula was determined in 1865.

Question 8.
Prepare a table showing depositional and erosional features separately.
Answer:

Question 9.
What are the natural realms of the Earth?
Answer:
There are four natural realms of the earth. They are

1. Lithosphere
2. Hydrosphere
3. Atmosphere and
4. Biosphere.

Question 10.
What are called plates?
Answer:
The massive base of rocks on which all the continents and even the oceans are actually situated are called plates.

Question 11.
What is called sea-floor spreading?
Answer:
The eruptions on the mid-ocean ridge create new ocean floor made of basalt rocks, which then spread literally from the ridge and this newest crust slowly pushes the plate away from the ridge, which is called ‘sea-floor spreading’.

Question 12.
What is Lithosphere?
Answer:
Lithosphere is the solid crust or the hard top part of the Earth. It is made up of rocks and minerals. It is covered with a thick layer of soil.

Question 13.
How many major plates are there on the earth? What are they?
Answer:
There are six major plates on the earth. They are African, North American, South American, Indo Australian, Antarctic, Eurasian and Pacific plates.

Question 14.
What is meant by intrusive landforms?
Answer:
Intrusive landforms :
Some part of the lava may not reach the surface and may cool under the surface and become rocks; These are called ‘intrusive landforms’.

Question 15.
Which are called ‘Third order landforms?
Answer:
The shaping of the landforms by wind and water is called ‘Third order landforms’ by geographers.

Question 16.
How is lithosphere useful to mankind?
Answer:

• Lithosphere is the solid crust or the hard top part of the earth.
• When it heats due to sunrays or cools down, it influences air and water too.
• We and most other living beings live on this realm.
• We use the rocks and soils and other things found in this hard crust in many ways.

Question 17.
What is the impact of vegetation on lithosphere?
Answer:

• Trees, plants and grass constitute vegetation.
• Vegetation contribute to the weathering of rocks by driving roots into fine cracks or holes in the rocks.
• They also enable water and moisture to enter into rocks which further enable weathering.
• On the other hand plant or grass cover on soils prevent easy denudation or transportation of soil by wind or water.

Question 18.
Which processes cause the formation of ‘Third Order landforms’?
Answer:

• The shaping of landforms by wind and water are called ‘third order landforms’.
• They include carved mountains, valleys, deltas, sand dunes, etc.
• Processes like weathering, erosion, transportation, and deposition are largely responsible for these landforms.

Question 19.
What do you mean by geomorphic cycle?
Answer:

• Landforms continuously keep on changing due to denudation activities.
• But these changes occur very slowly.
• The structure of mountains, plateaus and plains keep on changing through process known as ‘erosion cycle’ or ‘geomorphic cycle’.

Question 20.
How are gorges formed?
Answer:

• A gorge is almost equal in width at its top as well as its bottom.
• The Byson gorge in Andhra Pradesh on the Godavari, Indus gorge in Kashmir etc., are examples.
• Where the rocks are very hard, the river cuts a narrow valley, the sides are so steep that these ‘gorges’ are formed.

Question 21.
What is a canyon?
Answer:

• A canyon is characterised by steep like side slopes and may be as deep as a gorge.
• A canyon is wider at its top than bottom.

Question 22.
How ocean rocks or crust are formed?
Answer:
These are formed by lava rising up from the mantle. The eruptions on the ridges create new ocean floor made of basalt rocks, which then spreads laterally from the ridge. The first order landforms such as oceans and continents are formed at the time when the hot earth was cooling. While the earth’s interior continued to cool, it contracted and the outer crust wrinkled forming ridges i.e., mountains and basins i.e., oceans.

The second order landforms such as plains, plateaus and mountains are formed as a result of the internal processes of the earth. The third order landforms such as carved mountains, valleys, deltas, sand dunes are formed as a result of the shaping of the land forms by wind, water.

Question 23.
What are the four main “realms” of the earth? Explain how a cement factory world impact the various “realms”.
Answer:

• Realms are areas which have some common features.
• There are four major natural realms on the earth.
• They are :
  1. Lithosphere,
  2. Hydrosphere,
  3. Atmosphere and
  4. Biosphere.
• Cement factory is a mineral based industry.
• Unscientific way of mining may lead to earthquakes.
• Excessive emission of gases and dust may lead to air pollution.
• Heating of limestone and clay may emit mercury which may damage the brains of the children.

Question 24.
Write about “Plate tectonics”.
(OR)
What is plate tectonics?
Answer:

• The region where the two plates meet and push each other, a lot of pressure is exerted.
• One plate is pushed under into the mantle while the other plate is pushed up, to form a chain of mountains.
• This movement of plates is called ‘Plate tectonics’.

Question 25.
What are the two kinds of changes happening in the Lithosphere?
Answer:

• There are two kinds of changes taking place in the lithosphere.
• They are :
  a. The slow movement
  b. The sudden movement.
  3) The slow movement leads to the formation of the crust.
  4) The sudden movements (eruption of volcanoes and earthquakes) can be destructive and cause much damage.

Question 26.
How are Igneous rocks formed?
Answer:

• When volcano erupts, the molten material (also accompanied by steam, smoke and various gases) comes out from the depths of the earth.
• The molten materials cool on the earth and form hard rocks called “Igneous rocks”.

Question 27.
Write about “Intrusive landforms” and “Extrusive landforms”.
Answer:

• When volcano erupts, some part of the lava may not reach the surface and may cool under the surface and become rocks which are called “intrusive landforms”.
• A part of the lava which pours on the surface of the earth forms the “extrusive landforms”.

Question 28.
List out landforms originated due to the work of waves.
Answer:

• The erosion and deposition by the sea waves give rise to coastal landforms.
• “Sea Arches”, “Sea Cliff’, Cape, Bay and beaches are formed due to the work of the waves.

Question 29.
From which Greek word is the word Hydrosphere derived?
Answer:
It comes from the Greek word ‘hudor’ meaning water.

Question 30.
Write about the word Atmosphere.
Answer:
“Atmosphere” is derived from two greek words “atmos” means vapour and “sphaira” means sphere or ball.

Question 31.
Name few volcanoes that are situated in India.
Answer:
The Barren islands, and Narcondam are volcanoes situated in India.

Question 32.
What is weathering?
Answer:
The gradual disintegration of rocks by atmospheric forces or weather forces is called weathering.

Question 33.
What is erosion?
Answer:
The active wearing away of the earth’s surface, by different agents, is called erosion.

Question 34.
“The Earth is a deeply interconnected system” – Interpret the statement.
Answer:
The Earth consists of four major realms.

1. Lithosphere,
2. Hydrosphere,
3. Atmosphere and
4. Biosphere.

All these four are interrelated. All these four spheres together help the birth, existence, and continuance of life on Earth. Life needs the presence of all the other three realms land, water, and air. Life resides in the intersection of the three natural spheres. Life also actively changes the three other realms.

We cannot think of one realm without the crucial role of others. We cannot tamper with one aspect of it without affecting everything around us including ourselves. Thus we can say that the Earth is a deeply inter connected system.

Question 35.
“One day in very distant future the land you are standing upon will go under the Himalayas” – Interpret the above statement.
Answer:
At the margins of the plates where one plate meets another often the incoming plate dips under the stable plate. In fact the incoming plate actually goes into the mantle of the earth and becomes molten due to the heat of the mantle.

The plate thus going under into the mantle actually pulls the rest of the plate with it. For example, the Indian plate pushes the Eurasian plate and goes under if where the Himalayan mountains are.

Thus one day in very distant future the land we are standing upon will go under the Himalayas and join the mantle.

Question 36.
“The low lands what we see today were once mountains and plateaus” – Explain.
Answer:
External forces like water and air work vigorously to wear away the surface and the interaction of these constructive and destructive forces gives rise to the great diversity of present day landforms. These external processes on one hand wear away the surface of the rocks and mountains then they transport the wornout particles and deposit them in low lands and basins.

The processes of wearing away and deposition cause a general leveling of the surface. Processes like weathering, erosion, transportation and deposition are largely responsible for these landforms. It is known as denudation process.

Denudation is a continuous process. The landforms continuously keep on changing due to denudation activities. But these changes occur very slowly. Thus the low lands what we see today were once mountains and plateaus.

Question 37.
Read the paragraph and answer the following questions.
In some cases, where the rocks are very hard, the river cuts a very narrow valley, the sides are so steep that ‘Gorges’ are formed. The Byson gorge in A.P. on the Godavari, Indus Gorge in Kashmir are examples of this. Another important erosion form is Canyon. A Canyon is characterized by steep side slopes and may be as deep as a gorge. A gorge is almost equal in width at its top as well as its bottom.
1) Write any two similarities between gorges and canyons?
Answer:
a) It is as deep as gorge.
b) Both are formed with work of water.

2) Write any two differences between gorges and canyons?
Answer:
a) Canyon has a steep like side slope whereas gorge is too steep without side slope.
b) Canyon is wider at the top than at the bottom. Whereas Gorge is almost equal in width at its top as well as at its bottom.

3) Give an example of canyon.
Answer:
The Grand canyon on river Colorado.

4) How are gorges useful ?
Answer:
Gorges are suitable for construction of dams.

Question 38.
Last year (2015) Nepal witnessed a devastating earthquake. Learn about it.
Answer:

• Earthquake occured on 25th April 2015 and after shocks were felt on 12 May, 26th April, and 25th November of 2015.
• With a magnitude ranging from 7.8 to 8.1 on Richter scale, it caused a huge damage of about $ 5 billion.
• Nepal suffered 8,857 deaths and 21,952 persons were injured along with India, China, and Bangladesh.
• It’s hypocenter was at a depth of 8.21 cm and with epicenter was at east of district of hamjung.
• UNESCO world heritage sites in Khatmandu valleys and temples were damaged.
• It also triggered avalanche on Mount Everest causing as many as 200 deaths.
• It was believed to be the worst earthquake. Nepal suffered after 1934 Nepal-Bihar earthquake.

Question 39.
1. Locate different continents and oceans on the given world map.
Answer:

1. Asia
2. Europe
3. Africa
4. North America
5. South America
6. Australia
7. Pacific Ocean
8. Indian Ocean
9. Antarctic Ocean
10. Atlantic Ocean
11. Arctic Ocean

Question 40.
Observe the map and answer the following questions.

Which parts of India lie near plate margins?
Answer:

• The states of Gujarat, Rajasthan, Jammu and Kashmir lie near plate margins.
• So these areas are earthquake prone areas.

Question 41.
Label the patrs to the given diagram.
Answer:

1. Magma chamber
2. Lava
3. Central vent
4. Layers of lava and ash from past eruptions
5. Side vent

Question 42.
Why do you think glaciers make U-shaped valleys while rivers make V-shaped valleys?
Answer:
The shape of the trail left by the glacier is a function of the ice’s pressure on the ground. So if you look at the cross-section of a glacier is the laziest pattern the glacier can make, i. e. U. So the glaciers make U-shaped valleys.

In the high mountains, the flow of a river is very swift as it descends the steep slopes and it exerts a great force in cutting the mountain vertically. As a result a deep valley develops, narrow at the bottom and wide at the top. Thus V-shaped valleys are formed.

Question 43.
Appreciate the benefit with the eruption of a volcano?
Answer:

• There are various benefits with the eruption of volcano.
• Fertile soils are formed, like ones in deccan plateau.
• Valuable minerals from interior of the earth were brought to the surface or nearer to it.
• The soils formed like this are proved to be most populous areas, like in Java island.

AP State Syllabus AP Board 9th Class Physical Science Solutions Chapter 1 Motion Textbook Questions and Answers.

AP State Syllabus 9th Class Physical Science Solutions 1st Lesson Motion

9th Class Physical Science 1st Lesson Motion Textbook Questions and Answers

Improve Your Learning

Question 1.
As shown in following figure, a point traverses the curved path.
Draw the displacement vector from given points A to B.

Answer:

As the point traverses from A to B, the displacement is the shortest distance between A and B. Hence the displacement vector will be as follows.

Question 2.
“She moves at a constant speed in a constant direction.” Rephrase the same sentence in fewer words using concepts related to motion. (AS 1)
Answer:
“She moves with constant velocity”.

Reason :
Constant speed in a constant direction is nothing but ‘constant velocity’.

Question 3.
What is the average speed of a Cheetah that sprints 100 m in 4 sec? What if it sprints 50 m in 2 sec? (AS 1, AS7)
Answer:

Question 4.
Correct your friend who says, “The car rounded the curve at a constant velocity of 70 km/h”. (AS 1)
Answer:
“The car rounded the curve at a constant speed of 70 km/h”.

Reason :
In a circular motion, speed remains constant but velocity changes.

Question 5.
Suppose that the three balls shown in figure below start simultaneously from the top of the hills. Which one reaches the bottom first? Explain.

Answer:
Ball from first hill reaches the bottom first.
Reason :

1. In the first hill, the ball has uniform rectilinear motion.
2. So, the speed and velocity have same magnitude and direction.
3. In the second and third hills, the ball takes curved path.
4. So, the direction of velocity changes.

Question 6.
In the figure given below distance vs time graphs showing motion of two cars A and B are given. Which car moves fast? (AS 1)

Answer:
Car A moves fast.

Reason :

1. If we draw perpendiculars to X and Y axes from A and B respectively, we can observe that A covers large distance (S₁) within a short time (t₁).
2. Find the slopes of the lines OA and OB at any instant. Slope of OA is high. Hence car A moves faster.

Question 7.
Draw the distance vs time graph when the speed of a body increases uniformly. (AS 5)
Answer:
Let us consider a car moves as shown in the table.

Now draw a s-t graph.

Question 8.
Draw the distance-time graph when its speed decreases uniformly. (AS 5)
Answer:
Let us consider the movement of a car after applying brakes.

Now draw distance-time graph.

Question 9.
A car travels at a speed of 80 km/h during the first half of its running time and at 40 km/h during the other half. Find the average speed of the car. (AS 1, AS 7)
Answer:
Let the total running time = x hrs

Question 10.
A car covers half the distance at a speed of 50 km/h and the other half at 40 km/h. Find the average speed of the car. (AS 1, AS 7)
Answer:
Let the total distance = x km.
First half is covered with a speed of 50 km/h.

Question 11.
Derive the equation for uniform accelerated motion for the displacement covered in its n^th second of its motion. (s_n = u + a ( n – \(\frac{1}{2}\)) (AS 1)
Answer:
We know that distance travelled by an object in t seconds Is s = ut + \(\frac{1}{2}\) at²
∴ Distance travelled in ‘n’ seconds, s_{(n sec)} = un + \(\frac{1}{2}\)an² ………. (1)
Distance travelled in (n – 1) seconds, s_{(n – 1)} = u(n – 1) + \(\frac{1}{2}\) a(n – 1)² …….. (2)

Question 12.
A particle covers 10m in first 5 sec and 10m in next 3 sec. Assuming constant acceleration. Find initial speed, acceleration and distance covered in next 2 sec. (AS 1, AS 7)
Answer:
Distance covered in first 5 sec = 10

To find the distance covered in next 2 sec, we have to find the initial speed after 8 sec
i.e., the final velocity after 8 sec.

Question 13.
A car starts from rest and travels with uniform acceleration ‘α’, for some time and then with uniform retardation ‘β’ and comes to rest. The time of motion is “t”. Find the maximum velocity attained by it. (αβt/(α+β)) (AS 1, AS 7)
Answer:
Acceleration a = a m/sec²
Initial speed u = 0 m/sec
Let the time be t₁ sec.
From equation v = u + at
⇒ v = 0 + αt₁
\(\therefore \mathrm{t}_{1}=\frac{\mathrm{v}}{\alpha} \mathrm{sec}\)
Retardation a = – β m/sec²
Initial speed ‘u’ is equal to the final
velocity with acceleration ‘α’
= u = αt₁ m/sec
Final velocity v = 0 m/sec
Let the time be t₂ sec

Question 14.
A man is 48m behind a bus which is at rest. The bus starts accelerating at the rate of 1 m/s², at the same time the man starts running with uniform velocity of 10 m/s. What is the minimum time in which the man catches the bus? (AS 1, AS 7)
Answer:
Bus is at rest.
∴ u = 0; a = 1 m/sec²
Let the bus cover the distance ‘s’ in ‘n’ seconds.

A man running with uniform velocity, v = 10 m/sec.
Distance covered by man in n seconds = 10 nm.
But after ‘n’ seconds the man catches the bus.

∴ The minimum time in which the man catches the bus is 8 sec.

Question 15.
A body leaving a certain point “O” moves with a constant acceleration. At the end of the fifth second, its velocity is 1.5 m/s. At the end of the sixth second, the body stops and then begins to move backwards. Find the distance traversed by the body before it stops. Determine the velocity with which the body returns to point “0”. (AS 1)
Answer:
Velocity in 5^th sec = 1.5 m/sec ; The body comes to rest in 6^th sec.
∴ Final velocity in 6^th sec, v = 0
∴ Acceleration in 6^th sec is v = u + at ⇒ 0 = 1.5 + a. 1 ⇒ a = -1.5 m/sec²
[The velocity in 5^th sec becomes the initial velocity for 6^th sec]

After 6 sec, the body comes to rest.
∴ v = 0, a = -1.5 m/sec², u = ?, t = 6 sec.
v = u + at ⇒ 0 = u – 1.5 × 6 ⇒ u = 9 m/sec.
∴ Distance traversed by the body in 6 sec. i.e., before it stops.
s = ut + \(\frac{1}{2}\) at² = 9 × 6 + \(\frac{1}{2}\) × – 1.5 × 6² = 54 – 27 = 27m.
For backward journey,
u = 0 m/sec, t = 6 sec, a = -1.5 m/sec²
v = u + at ⇒ v = 0 – 1.5 × 6 ⇒ v = – 9
∴ Velocity for backward journey is – 9 m/sec.

Question 16.
Distinguish between speed and velocity.(AS 1)
Answer:

Question 17.
What do you mean by constant acceleration? ((AS 1)
Answer:

• Acceleration is the rate of change of velocity.
  2
• It gives an idea how quickly velocity of a body is changing.
• Acceleration is uniform, when in equal intervals of time, equal changes of velocity occurs.
• For example, while driving a car, if we steadily increase the velocity from 30 km/h to 35 km/h in 1 sec and 35 km/h to 40 km/h in the next second and so on. In this case the acceleration is 5km/h, is said to be constant acceleration.
  

Question 18.
When the velocity is constant, can the average velocity over any time interval differ from instantaneous velocity at any instant ? If so, give an example; if not, explain why. (AS 2, AS 1)
Answer:
No. Here velocity is constant.
∴ Average velocity over any time interval is same and the instantaneous velocity at any instant is same.

Ex : Let us consider a car moves on a straight road with constant velocity say 10 m/s.
1) Now let the distance covered (AB) by the car in 1 s = 10 m.

2) Distance covered in 2s (AC) = 20 m.
Average velocity from A to C is \(\frac{20 m}{2 s}\) = 10 m/s.

3) Instantaneous velocity at A or B or C at any point = 10 m/s.

Question 19.
Can the direction of velocity of an object reverse when its acceleration is constant? If so give an example; if not, explain why? (AS 2, AS 1)
Answer:
Yes. In case of a vertically projected body, while the body is moving up, the direction of velocity is upward, whereas while it is falling down, the direction of velocity is downward. Acceleration in both the cases is constant (numerically).

Question 20.
A point mass starts moving in a straight line with constant acceleration V’. At a time t after the beginning of motion, the acceleration changes sign, without change in magnitude. Determine the time t0 from the beginning of the motion in which the point mass returns to the initial position. (AS 1)
Answer:

Question 21.
Consider a train which can accelerate with an acceleration of 20 cm/s² and slow down with deceleration of 100 cm/s². Find the minimum time for the train to travel between the stations 2.7 km apart. (AS 1)
Answer:
Let the Acceleration of the train a = 20 cm/s²
Deceleration of the train β = 100 cm/s²
Distance between the two stations s = 2.7 km = 27 × 10⁴ cm
Let the minimum time for the train to travel between the two stations is t sec.

Question 22.
You may have heard the story of the race between the rabbit and tortoise. They started from same point simultaneously with constant speeds. During the journey, rabbit took rest somewhere along the way for a while. But the tortoise moved steadily with lesser speed and reached the finishing point before rabbit. Rabbit woke up and ran, but rabbit realized that the tortoise had won the race. Draw distance vs time graph for this story. (AS 5)
Answer:

1. OX – movement of tortoise.
2. OABC – movement of rabbit
3. Rabbit and tortoise start at O’.
4. After time tj rabbit is at A and tortoise is at P.
5. Rabbit takes rest up to time t₂.
6. After time t₂, tortoise is at Q, but rabbit has no displacement.
7. After time t₃, the tortoise reaches the destination ‘X’.
8. But rabbit reaches the destination after time t₄.

Question 23.
A train of length 50 m is moving with a constant speed of 10 m/s. Calculate the time taken by the train to cross an electric pole and a bridge of length 250 m. (AS 1)
Answer:
Length of the train 50 m.; Speed of the train v = 10 m/s.
Distance travelled while crossing an electric pole = Length of the train = s = 50 m.
∴ Time taken to cross the electric pole ‘t’ = \(\frac{s}{v} \Rightarrow t=\frac{50}{10}\) = 5 s.
Length of the bridge = 250 m.
Distance travelled while crossing the bridge = Length of train + Length of bridge
= 50 + 250 = 300 m.
∴ Time taken to cross the bridge = \(\frac{300 \mathrm{~m}}{10 \mathrm{~m} / \mathrm{s}}\) = 30 sec.

Question 24.
Two trains each of having a speed of 30 km/h are headed at each other in opposite direction on the same track. A bird flies off one train to another with a constant speed of 60 km/h when they are 60 km apart till before they crash. Find the distance covered by the bird and how many trips the bird can make from one train to the other before they crash. (AS 1)
Answer:
Speed of each train = 30 km/hr
Speed of the bird = 60 km/hr
Distance between the two trains = 60 km
These two trains crash in one hour.
The bird flies a distance of 60 km till before the two trains crash.
The bird can make number of trips (infinity) before they crash.

Question 25.
A Stone dropped from top of a well reaches the surface of water in 2 seconds, find the velocity of stone while it touches the surface of water and what is the depth of the water surface from top of well (g=10m/s²) (Using V = U + at, S = Ut + 1/2 at²)
Answer:
Given that
t = 2s
u = 0 m/s [∵ free fall body]
v = ?
Depth s = ?
a = g = 10 m/s²

i) v = u + at
v = 0 + 10 × 2 = 20 m/s

ii) s = ut + – \(\frac{1}{2}\)at²
= 0 + \(\frac{1}{2}\) × 10 × 2²
= \(\frac{1}{2}\) × 10 × 4
= 20 m
Hence, velocity of stone while it touches the surface of water = 20 m/s
Depth of the water surface from the top of well = 20 m.

Question 26.
An object moving with 6m per second execute an acceleration 2 m/s² in next 3 seconds. How much distance it covered? (s = ut + 1/2 at²)
Answer:
u = 6 m/s; t = 3 sec; a = 2 m/s²
s = ut + \(\frac{1}{2}\) at²
= 6 × 3 + \(\frac{1}{2}\) × 2 × 3² = 18 + 9 = 27 m
The object covers 27 m in 3 sec.

Question 27.
A car stopped after travelling distance 8 m due to applying brakes at the speed of 40 m/s. Find acceleration and retardation of car in that period, (v² – u² = 2as)
Answer:
Here u = 40 m/s; v = 0 (vehical stopped); s = 8 m; a =?
v² – u² = 2as 0 – 40² = 2 × a × 8
a = \(\frac{-(40)(40)}{2 \times 8}\) =-100m/s
Acceleration = 100 m/s² with retordation on (-sign).

9th Class Physical Science 1st Lesson Motion InText Questions and Answers

9th Class Physical Science Textbook Page No. 1

Question 1.
If earth is in motion, why don’t we directly perceive the motion of the earth?
Answer:
Earth is in motion. We, the people on the earth also move with a speed equal to that of the earth. We cannot directly perceive the motion of the earth, because of this.

Question 2.
Are the walls of your classroom at rest or in motion? Why?
Answer:
The walls are at rest in view of our observation. When we discuss this in view of the motion of the earth, the walls are also in motion.

Question 3.
Have you ever experienced that the train in which you sit appears to move when it is at rest? Why?
Answer:
This happens when we sit in a stationary train and, the train on another track starts moving.

9th Class Physical Science Textbook Page No. 2

Question 4.
Why do we observe these changes?

Answer:
These changes are due to the point of observation. We know that earth is a sphere, the upward direction of the vertical position on its surface decisively depends upon the place on the earth’s surface, where the vertical is drawn.

Question 5.
Are the terms relative or not?
Answer:
The terms “longer”, “shorter”; “up” and “down”, etc. are relative to each other.

9th Class Physical Science Textbook Page No. 4

Question 6.
What answer may the passenger give to the driver?
Answer:
The car is in motion with respect to the observer on the road, but at rest with respect to the passenger. Because motion is a combined property of the observer and the body which is being observed.

Question 7.
How do we understand motion?
Answer:
A body is said to be in motion when its position is changing continuously with time relative to an observer.

9th Class Physical Science Textbook Page No. 6

Question 8.
Can you measure the average speed and average velocity?
Answer:
Yes, we can measure the average speed and average velocity.

Question 9.
How can you differentiate speed and average velocity?
Answer:

1. Speed gives the idea of how fast the body moves.
2. Velocity is the speed of an object in a specified direction.

9th Class Physical Science Textbook Page No. 7

Question 10.
Can you find the speed of the car at a particular instant of time?
Answer:
Yes, we can find the speed of the car at any instant of time by looking at its speedometer

Question 11.
What is the speed of the car at the instant of time ‘t₃‘ for given motion?
Answer:

The instantaneous speed is represented by the slope of the curve at a given instant of time. We can find the slope of the curve at any point on it by drawing a tangent to the curve at that point. The slope of the curve gives speed of the car at that instant.

9th Class Physical Science Textbook Page No. 8

Question 12.
In what direction does an object move? Distance vs time graph
Answer:
The object moves in the direction tangential to the direction of the motion of the string.

Question 13.
Which motion is called uniform? Why?
Answer:
The motion of the body is said to be in uniform when its velocity is constant.

9th Class Physical Science Textbook Page No. 9

Question 14.
What is the shape of the graph?
Answer:

The shape of the graph for a body which is in uniform motion is a straight line as shown in the figure.

9th Class Physical Science Textbook Page No. 10

Question 15.
a) What is the shape of the graph?
Answer:
It is a curve.

b) Is it a straight line or not? Why?
Answer:
The graph is not a straight line because the speed is changing irregularly.

Question 16.
Draw velocity vectors in the given figure at times t = 0, 1s, 2s, 3s.
Answer:

From the graph, we conclude that when the ball moves down the inclined plane its speed increases gradually but its direction remains constant.

9th Class Physical Science Textbook Page No. 11

Question 17.
Draw velocity vectors at times t = 1s, 2s, 3s in the given figure.
Answer:

From the graph, we conclude that when the ball moves up the inclined plane its speed decreases gradually, but the direction of motion remains constant.

Question 18.
Can you give few examples for motion of an object where its speed remains constant but velocity changes?
Answer:
For the bodies which are in uniform in circular motion the speed remain constant but velocity change. Ex : Rotation of earth, revolution of moon around the earth, etc.

Question 19.
Is the direction of motion constant? How?
Answer:
No, the direction of motion also changes continuously.

Question 20.
Can you give some more examples where speed and direction simultaneously change?
Answer:
Motion of a rocket, horizontally projected body, kicked football, a cricket ball bowled by a bowler, etc.

9th Class Physical Science Textbook Page No. 12

Question 21.
What is acceleration? How can we know that a body is accelerating?
Answer:

1. Acceleration gives an idea how quickly velocity of a body changing.
2. It is equal to the rate of change in velocity.
3. While travelling in a bus or car, when the driver presses the accelerator, the passen¬gers sitting in the bus experience acceleration. Their bodies press against the seats due to acceleration.

Question 22.
At which point is the speed maximum?
Answer:
At B, the speed will be maximum.

Question 23.
Does the object in motion possess acceleration or not?
Answer:
Any object which is in motion possesses acceleration.

9th Class Physical Science Textbook Page No. 5

Question 24.
What is the displacement of the body if it returns to the same point from where it started? Give one example from daily life.
Answer:
When a body returns to the same point where it is started, then the displacement is zero.
Ex: A man starts from his home, goes to a market and returns home. Then his displacement is zero.

Question 25.
When do the distance and magnitude of displacement become equal?
Answer:
The distance and the magnitude of displacement become equal when the body moves along a straight line in one direction.

9th Class Physical Science Textbook Page No. 6

Question 26.
What is the average speed of the car if it covers 200 km in 5 h?
Answer:
Distance = 200 km ; Time = 5 h

Question 27.
When does the average velocity become zero?
Answer:
The average velocity of a body becomes zero when its displacement is zero.

Question 28.
A man used his car. The initial and final odometer readings are 4849 and 5549 respectively. The journey time is 25h. What is his average speed during the journey?
Answer:
Distance covered = 5549 – 4849 = 700 km.
Time = 25h.

9th Class Physical Science Textbook Page No. 9

Question 29.
Very often you must have seen traffic police stopping motorists or scooter drivers who drive fast and fine them. Does fine for speeding depend on average speed or instantaneous speed? Explain.
Answer:
Instantaneous speed.

Question 30.
One airplane travels due north at 300 km/h and another airplane travels due south at 300 km/h. Are their speeds the same? Are their velocities the same? Explain.
Answer:

1. Speed is same.
2. Velocities are same in magnitude but differs in direction in the observer’s point of view.

Question 31.
The speedometer of the car indicates a constant reading. Is the car in uniform motion? Explain.
Answer:
Yes.

1. The indicator in speedometer changes its position even for a small change in speed.
2. As it indicates a constant reading, the car moves equal distances at equal intervals of time.
3. Hence the motion is uniform.

9th Class Physical Science Textbook Page No. 11

Question 32.
An ant is moving on the surface of a ball. Does it’s velocity change or not? Explain.
Answer:
Velocity changes.
As the ant is moving on the surface of a ball, it has to go in circular motion.

Question 33.
Give an example of motion where there is a change only in speed but no change in direction of motion.
Answer:
Motion of a bus on the road.

9th Class Physical Science Textbook Page No. 13

Question 34.
What is the acceleration of a race car that moves at constant velocity of 300 km/h?
Answer:
Velocity = 300 km/h = \(300 \times \frac{5}{18}=\frac{500}{6}\) = 83.33 m/sec
As the velocity is constant, the acceleration is also constant.
∴ Acceleration = 83.33 m/sec².

Question 35.
Which has the greater acceleration, an airplane, that goes from 1000 km/h to 1005 km/h in 10s or a skateboard that goes from zero to 5km/h in 1 second?
Answer:

Question 36.
What is the deceleration of a vehicle moving in a straight line that changes its velocity from 100 km/h to a dead stop in 10 sec?
Answer:

Question 37.
Correct your Mend who says “Acceleration gives an idea of how fast the position changes.”
Answer:
“Acceleration gives the idea of how fast the position changes in a given direction.”

9th Class Physical Science 1st Lesson Heat Activities

Activity 1 Distance and Displacement

Question 1.
Draw a graph showing the difference between distance and displacement.
Answer:

• Take a ball and throw it into the air with some angle to the horizontal.
• Observe its path and draw it on paper.
• The figure shows the path taken by the ball.
• The distance ASB gives the distance travelled by the ball.
• The length of \(\overrightarrow{\mathrm{AB}}\) gives the displacement of the ball.

Displacement:
Displacement is the shortest distance between initial and final points in a specified direction represented by a vector.

Distance :
Distance is the length of the path traversed by an object in a given time interval.

Activitie – 2 Drawing displacement vectors

Question 2.
Draw displacement vectors from A to B in the following situations.

Answer:

Activitie – 3 Measuring the average speed

Question 3.
How can the average speed be measured?
Answer:

1. Select two positions (say A and B) 50 meters apart in the ground.
2. Ask some students to stand at point A.
3. Ask another group of students with stop watches to stand at B.
4. When you clap your hand, the students at A start running towards the point B in any direction or path.
5. At the same time the students at B start their stop watches.
6. Observe that for each runner there is a student at B to measure the time taken for completing the race.
7. Note the time taken by each student to cover the distance between the points A and B in the table given below.
   

   Student	Time taken to reach B (Sec.)	Average speed (50 ft) m/s
   A1	t1	………
   A2	t2	………
   A3	t3	………

8. The student who took the least time to reach B (from A) is said to be the fastest runner.
9. The student who is fastest runner has the greatest average speed.
10. Thus we measure the average speed of any moving body.

Activity – 4 Observing the direction of motion of a body

Question 4.
Show that the direction of velocity is tangent to the path at a point of interest when a body is in uniform circular motion.
Answer:

• Carefully whirl a small object on the end of the string in the horizontal plane.
• Release the object while it is whirling on the string.
• We observe that the body along the tangent at the point where we released the body.
• Try to release the object at different points on the circle and observe the direction of motion of object after it has been released form the string.
• We will notice that the object moves on a straight line along the tangent to the circle at the point where we released it.

Activity – 5 Understanding uniform motion

Question 5.
Describe uniform motion.
Answer:
1) Consider a cyclist moving on a straight road.
2) The distance covered by him with respect to time is given in the following table.

3) Draw distance vs time graph for the given values in the table.

4) The graph will be as shown in the figure.
5) The straight line graph shows that the cyclist covers equal distances in equal inter¬vals of time.
6) If the direction of motion of the cyclist is assumed as constant, then we conclude that velocity is constant.
7) The motion of the body is said to be uniform when its velocity is constant.

Activity – 6 Observing the motion of a ball on an inclined plane

Question 6.
Describe an activity to explain the situation that “the speed changes but the direction of motion remains constant”.
Answer:
1) Set up an inclined plane as shown in the figure.
2) Take a ball and release it from the top of the inclined plane.
3) The positions of the ball at various times are shown in the figure given below.

4) On close observation we find that when the ball moves down on the inclined plane, its speed increases gradually, and the direction of motion remains constant on inclined plane.
5) Now push the ball till it acquires certain speed and release it with that speed from the bottom of the inclined plane.

6) We observe that the ball moves upward to a certain distance and comes back to the bottom.
7) From this we conclude that the speed changes but the direction of motion remains constant.

Activity – 7 Observing uniform circular motion

Question 7.
Explain with an example where “speed remains constant, but its velocity changes”.
Answer:

• Whirl continuously a stone which is tied to the end of the string.
• Draw its path of motion and velocity vectors at different positions as shown in figure.
• Assume that the speed of stone is constant.
• We observe that the path of the stone is a circle, and the direction of velocity changes at every instant of time, but the speed is constant.
• In this activity, we observe that though speed remains constant, its velocity changes.

Activity – 8 Observing the motion of an object thrown into air

Question 8.
Explain an activity to observe where speed and direction of motion change continuously.
Answer:

• Throw a stone into the air by making some angle with the horizontal.
• The path of the stone and velocity vectors are as shown in the figure.
• Here we observe that the speed of stone is not uniform as it traverses different distances at different intervals of time and finally comes to rest.
• The direction of motion is also not constant, as shown by the velocity vectors.
• In this activity, we noticed that the speed and direc¬tion of motion both change continuously.

Lab Activity

Question 9.
Describe an activity to find the acceleration and velocity of an object moving on inclined track.
Answer:
Aim : To find the acceleration and velocity of an object moving on an inclined track. Materials required: Glass marbles, book, digital clock, long plastic tubes and steel plate.
Procedure:

• Take a long plastic U type flat electrical wire cassing channel of length nearly 200 cm. Use this channel as track.
• Mark the readings in cm, along the track.
• Place one end of the track on a book and the other end on the floor.
• Keep a steel plate on the floor at the bottom of the track.
• Consider the reading at the bottom of the track as zero.
• Take a marble having enough size to travel in the track freely.
• Now release the marble freely from a certain distance say 40 cm.
• Start the digital clock when the marble is released.
• It moves down on the track and strikes the steel plate.
• Stop the digital clock when a sound is produced.
• Repeat the same experiment for the same distance 2 to 3 times and note the values of times in the table.

• Repeat the same experiment or various distances.
• Draw s -1 graph for above values.
• Do the above experiment by various slopes of the track and find acceleration in each case.

Conclusions :

1. As the slope increases, acceleration increases.
2. When iron block is used, we obtain the same conclusion as above. (The numerical values are less than the numerical values when marble is used)

AP State Syllabus AP Board 9th Class Physical Science Solutions Chapter 2 Laws of Motion Textbook Questions and Answers.

AP State Syllabus 9th Class Physical Science Solutions 2nd Lesson Laws of Motion

9th Class Physical Science 2nd Lesson Laws of Motion Textbook Questions and Answers

Improve Your Learning

Question 1.
Explain the reasons for the following. (AS 1)
a) When a carpet is beaten with a stick, dust comes out of it.
Answer:

1. The dust particles in the carpet are at rest.
2. When the carpet is beaten with a stick, the state of rest of the dust particles is disturbed.
3. Due to inertia, the dust particles comes out.

b) Luggage kept on the roof of a bus is tied with a rope.
Answer:

1. Luggage kept on the roof of a bus is in the state of rest.
2. As the bus moves, the luggage also moves with a velocity equal to the velocity of the bus.
3. If the bus suddenly stops, the luggage resists to change its state of motion.
4. Hence due to inertia it will fall down.
5. To avoid this, the luggage is tied with a rope.

c) A pace bowler in cricket runs in from a long distance before he bowls.
Answer:

1. When he runs in from a long distance, he gains momentum of inertia.
2. Due to this larger inertia, larger force is applied in a short interval of time.
3. Hence the momentum will be more.

Question 2.
Two objects have masses 8 kg and 25 kg. Which one has more inertia? Why? (AS 1)
Answer:

1. The object with mass 25 kg has more inertia.
2. The resistance to change the state of object will be more for a body of larger mass.

Question 3.
Keep a small rectangular shaped piece of paper on the edge of a table and place an old five rupee coin on its surface vertically as shown in the figure below. Now give a quick push to the paper with your finger. How do you explain inertia with this experiment?

Answer:

1. The coin and the paper are in inertia of rest.
2. When we give a quick push to the paper, paper comes to inertia of motion and the coin remains in its original state i.e., inertia of rest.
3. As a result, the paper will come out and the coin remains on the table without changing its position.

Question 4.
If a car is travelling westwards with a.constant speed of 20 m/s, what is the resultant force acting on it? (AS 1, AS 7)
Answer:

1. A car is moving with a constant speed.
2. Hence the net force on the car is zero both in horizontal and vertical directions.

Question 5.
What is the momentum of a 6.0 kg bowling ball with a velocity of 2.2 m/s? (AS 1)
Answer:
Mass of the ball (m) = 6.0 kg
Velocity of the ball (v) = 2.2 m/s
Momentum (p) = nv = 6.0 kg × 2.2 m/s = 13.2 kg m/s (or) 13.2 N-s

Question 6.
Two people push a car for 3 sec, with a combined net force of 200 N. (AS 1)
a) Calculate the impulse provided to the car.
Answer:
F_net = 200 N ; ∆t =3 sec
Impulse ∆p = F_net. ∆t = 200 × 3 = 600 N – sec.

b) If the car has a mass of 1200 kg, what will be its change in velocity?
Answer:
Mass of the car (m) = 1200 kg.; Net force (F_net) = 200 N
Time ∆t = 3 sec. ; Change in velocity ∆v =?

Question 7.
What force is required to produce an acceleration of 3 m/sec2 in an object of mass 0.7 kg? (AS 1)
Answer:
Mass of the object (m) = 0.7 kg.; Acceleration (a) = 3 m/sec²
Force required (F) = ?
F = ma = 0.7 x 3 = 2.1 N

Question 8.
A force acts for 0.2 sec on an object having mass 1.4 kg initially at rest. The force stops to act but the object moves through 4 m in the next 2 seconds, find the magnitude of the force. (AS 1)
Answer:

Velocity after 0.2 sec v = u + at = 0 + 0.2 a = 0.2a ……….. (1)
After 0.2 s, the body moves with uniform velocity, acceleration is zero, because force is removed.
∴ Velocity v = \(\frac{s}{t}=\frac{4}{2}\) =2 m/s. ………. (2)
From (1) & (2)
v = 0.2a ⇒ 2 = 0.2a
⇒ a = \(\frac{2}{0.2}\) = 10 m/s²
∴ Force applied F = ma = 1.4 kg × 10 m/s² = 14 N.

Question 9.
An object of mass 5 kg is moving with a velocity of 10 ms^-1. A force is applied so that in 15 s, it attains a velocity of 25 ms^-1. What is the force applied on the object? (AS 1)
Answer:
Mass (m) = 5 kg ; Initial velocity (u) = 10 m/s.; Time (t) = 15 s
Final velocity (v) = 25 m/s.
Acceleration a = \(=\frac{v-u}{t}=\frac{25-10}{15}=\frac{15}{15}=1 \mathrm{~m} / \mathrm{s}^{2}\).
Force applied on the object F = ma = 5 × 1=5 N.

Question 10.
Find the acceleration of body of mass 2 kg from the figures shown. (AS 1)

Answer:
1) Force 30 N is acting downwards on weight of (2 × 10) = 20 kg.
The acceleration a = \(\frac{30-20}{2}=\frac{10}{2}\) = 5 m/s²

2) m₁ = 2 kg, m₂ = 3 kg.
m₂ pulls the body mt with a weight 3 × 10 = 30 N.
∴ Acceleration of m₁ = \(\frac{30-20}{3+2}=\frac{10}{5}\)
= 2 m/s².

Question 11.
Take some identical marbles. Make a path or a track keeping your notebooks on either side so as to make a path in which marbles can move. Now use one marble to hit the other marbles. Take two, three marbles and make them to hit the other marbles. What can you explain from your observations? (AS 5)
Answer:

1. When one marble is hit by another marble, both the marbles move with some velocity.
2. When the marble is hit by two, three marbles, all marbles move with a velocity which is more than in the previous case.
3. As we are hitting with more marbles, the mass increases. So that the net momentum also increases.

Question 12.
A man of mass 30 kg uses a rope to climb which bears only 450 N. What is the maximum acceleration with which he can climb safely? (AS 1, AS 7)
Answer:
Mass m = 30 kg. ; Force F = 450 N
Acceleration a = ?
F = ma
∴ a = \(\frac{\mathrm{F}}{\mathrm{m}}=\frac{450}{30}\) =15 m/sec²
∴ The required acceleration =15 m/sec²

Question 13.
An vehicle has a mass of 1500 kg. What must be the force between the vehicle and the road if the vehicle is to be stopped with a negative acceleration of 1.7 m/sec²? (AS 1, AS 7)
Answer:
Mass of the vehicle, m = 1500 kg.; Acceleration (-a) = 1.7 m/sec²
Force, F =?
F = m (-a) = 1500 × (-1.7) = ( – ) 2550 N
∴ The force between the vehicle and road is 2550 N, in the direction opposite to that of the vehicle.

Question 14.
If a fly collides with the windshield of a fast moving bus, is the impact force experienced, same for the fly and the bus? Why? (AS 1, AS 2)
Answer:
The impact force experienced by the fly will be more, because the mass of fly is negligible when compared to the mass of the bus.

Question 15.
A truck is moving under a hopper with a constant speed of 20 m/sec. Sand falls on the truck at a rate 20 kg/s. What is the force acting on the truck due to falling of sand? (AS 1, AS 7)
Answer:
Mass of the sand falling on the truck in 1 sec = 20 kg
Constant speed of the truck = 20 m/s
Acceleration in 1 sec, a = \(\frac{\Delta v}{\Delta t}=\frac{20}{1}\) = 20 m/sec²
Force applied on the truck, F = ma = 20 kg x 20 m/sec² = 400 N

Question 16.
Two rubber bands stretched to the standard length cause an object to accelerate at 2 m/sec². Suppose another object with twice the mass is pulled by four rubber bands stretched to the standard length. What is the acceleration of the second object? (AS 1)
Answer:
First object:
Let the force applied by two rubber bands = F₁ Newton
Mass of the object = m₁ kg; Acceleration a₁ = 2 m/sec²
We know F = ma
F₁ = m₁ × 2
⇒ F₁ = 2m₁ …….(1)

Second object:
The force applied by 4 rubber bands = 2F₁ Newton
Mass of the object = 2m₁ kg ; Acceleration a₂ =?
We know F = ma
2F₁ = 2m₁. a₂

∴ Acceleration of the second object = 2 m/sec²

Question 17.
Illustrate an example of each of the three laws of motion. (AS 1)
Answer:
First law of motion :
A body continues its state of rest or of uniform motion unless a net force acts on it.
Ex:

1. When the bus which is at rest begins to move suddenly, the person standing in the bus falls backward.
2. When you are travelling in bus, the sudden stop of the bus makes you fall forward.

Second law of motion :
The rate of change of momentum of a body is directly proportional to the net force acting on it and it takes place in the direction of net force.
Ex : Place a ball on the veranda and push it gently. Then the ball accelerates from rest. Thus, we can say that force is an action which produces acceleration.

Third law of motion :
If one object exerts a force on the other object, the second object exerts a force on the first one with equal magnitude but in opposite direction.

Ex :

1. When birds fly, they push the air downwards with their wings, and the air pushes back the bird in opposite upward direction.
2. When a fish swims in water, the fish pushes the water back and the water pushes the fish with equal force but in opposite direction.
3. A rocket accelerates by expelling gas at high velocity. The reaction force of the gas on the rocket accelerates the rocket in a direction opposite to the expelled gases.

Question 18.
Two ice-skaters initially at rest, push of each other. If one skater whose mass is 60 kg has a velocity of 2 m/s. What is the velocity of other skater whose mass is 40 kg? (AS 1, AS 7)
Answer:
Mass of first skater m₁ = 60 kg.;
Velocity of first skater v₁ = 2 m/s.
Mass of second skater m₂ = 40 kg.; Velocity of second skater v₂ =?
As the two skaters push each other, the resultant momentum will become zero.
The resultant momentum m₁v₁ + m₂v₂ = 0

∴ Velocity of second skater is 3 m/s, but in the direction opposite to the first skater.

Question 19.
A passenger in moving train tosses a coin which falls behind him. It means that the motion of the train is (AS 7)
a) Accelerated
b) Uniform
c) Retarded
d) Circular motion
Answer:
a) Accelerated

Question 20.
A horse continues to apply a force in order to move a cart with a constant speed. Explain. (AS 1)
Answer:

1. The cart moves when the force (in the form of pulling) is applied by the horse.
2. As the horse and cart are moving, the net momentum will be zero at any instance of time.
3. Hence when the horse comes to rest, the cart also comes to rest.
4. To avoid this and to move the cart with a constant speed, the horse must apply force continuously.

Question 21.
A force of 5 N produces an acceleration of 8 m/sec² on a mass m, and an acceleration of 24 m/sec² on a mass m₂. What acceleration would the same force provide If both the masses are tied together? (AS 1)
Answer:
For the first mass (m₁)
Force F = 5 N
Acceleration a = 8 m/s²
We know, F = ma
5 = m, . 8
m₁= \(\frac{5}{8}\) kg

For the second mass (m₂)
Force F = 5 N
Acceleration a = 24 m/sec²
We know, F = ma
5 = m₂.24
m₂ = \(\frac{5}{24}\) kg
When both the masses are tied together and the same force is applied, then

Question 22.
A hammer of mass 400 g, moving at 30 m/s, strikes a nail. The nail stops the hammer in a very short time of 0.01 s. What is the force of the nail on the hammer? (AS 1)
Answer:
Mass of the hammer (m) = 400 g = 0.4 kg. ; Velocity of the hammer (v) = 30 m/s.
Momentum (∆p) = 30 × 0.4 N – s.
The nail stops the hammer with in a time 0.01 s.
∴ ∆t = 0.01 s.
The stopping force of the nail on the hammer.

Question 23.
System is shown in figure. Assume there is no friction. Find the acceleration of the liloc-ks-and tension in the string. Take g = 10 m/s² (AS 1)

Answer:
m₁ = 3 kg, m₂ = 3 kg.
1) Acceleration ’a’ and tension T on m₁ are shown in figure.
2) Acceleration a and tension T will be as shown in figure.

Normal force = weight 3s – T = 3a ………… (2)
∴ only tension applied
Tension T = 3 kg × a = 3a
From (1) & (2)
3g – 3a = 3a ⇒ 3g = 6a ⇒ a = \(\frac{3 g}{6}=\frac{3 \times 10}{6}\) = 5 m/s².
Tension T = 3a = 3 × 5 = 15 N.

Question 24.
Three identical blocks, each of mass 10 kg, are pulled as shown on the hoii ;ontal frictionless surface. If the tension (F) in the rope is 30 N, what is the acceleration oi each block? And what are the tensions in the other ropes? (Neglect the masses of the ropes) (AS 1)

Answer:
Three blocks, each of mass 10 kg are pulled by a rope.
∴ Total mass = 10 + 10 + 10 = 30 kg
Force applied by the rope, F = 30 N
∴ Acceleration of each block, a = \(\frac{F}{m}=\frac{30}{30}\) = 1 m/sec².

Tension in first rope (T₁)
First rope pulls only one block whose mass is 10 kg with an acceleration 1 m/sec².
∴ F = ma = 10 kg × 1 m/sec² = 10 N

Tension in second rope (T₂)
Second rope pulls two blocks, each of mass 10 kg.
∴ Total mass = 10 + 10 = 20 kg.
Acceleration, a = 1 m/sec²
Force, F = ma = 20 × 1 = 20 N

Question 25.
A ball of mass’m’ moves perpendicularly to a wall with a speed v, strikes it and rebounds with the same speed in the opposite direction. What is the direction and magnitude of the average force acting on the ball due to the wall? (AS 7)
Answer:
According to the Newton s third law of motion,
Force exerted by ball on the wall = – (Force exerts by the wall on the ball)
∴ F_B.W = – F_W.B
Force exerted by ball :
Mass of ball = m, speed = v, F_BW = ma = \(\frac{\mathrm{m} \cdot \mathrm{v}}{\mathrm{t}}\)
As the wall is at rest and exerts some force on the ball of mass m, then it moves in the other direction with the same speed.

Question 26.
Divya observed a horse pulling a cart. She thought that cart also pulls the horse with same force in opposite direction. As per third law of motion, the cart should not move forward. But her observation of moving cart raised some questions in her mind. Can you guess what questions are raised in her mind? (AS 2)
Answer:

• According to Newton’s third law, when horse pulls a cart, the cart also pulls the horse with same force but in opposite direction. So the cart has to stop. Why is the cart moving?
• What is the effect of friction of ground on the cart and horse?
• Does the cart continue to move even if the horse stops pulling it?
• What makes the cart to move continuously?
• Does it become an isolated system?
• What is the action and reaction in this system?

Question 27.
How do you appreciate Galileo’s thought of “any moving body continues in the stale only until some external force acts on it”, which is contradiction to the Aristotle’s belief of “any moving body naturally comes to rest”? (AS 6)
Answer:

• Science is dynamic.
• All theories can change time to time so that the science and technology will be developed.
• Aristotle’s belief proved to be wrong only by the experiments conducted by Galileo.
• So anybody can challenge the existing theories with proper experimentation.
• Aristotle’s and Galileo’s contradictory thought lead Newton to propose most popular laws of motion.
• Newton’s third law of motion is the basic principle in rocket launching.
• Nowadays we are enjoying the results of satellites launched by rockets.
• Hence comfortable life is the effort on experiments, theories, and calculations made by scientists with a zeal to invent new.

9th Class Physical Science 2nd Lesson Laws of Motion InText Questions and Answers

9th Class Physical Science Textbook Page No. 24

Question 1.
Do all the bodies have the same inertia?
Answer:
The inertia of all bodies is not same. It depends on the mass of the object.

Question 2.
What factors can decide the inertia of a body?
Answer:
Mass is the factor, which decides the inertia of a body.

9th Class Physical Science Textbook Page No. 26

Question 3.
Is the acceleration increased when net force is increased?
Answer:
Yes, the acceleration increased, as we increased the net force without changing mass of the object.

9th Class Physical Science Textbook Page No. 29

Question 4.
What do you notice from the readings in the spring balances?
Answer:
The two spring balances stretch up to a certain limit equally.

Question 5.
Are the readings of two spring balances the same?
Answer:
Yes, the readings of two spring balances are equal.

Question 6.
Are we able to make the spring balances to show different readings by pulling them simultaneously in opposite directions? Why not?
Answer:
When same force is applied in both the directions, we are unable to make the spring balances to show different readings because the action and reaction are same in magnitude and opposite in direction. When we use two forces with different magnitudes, then the spring balances can show different readings.

9th Class Physical Science Textbook Page No. 30

Question 7.
Does the rocket exert a force on the gas expelled from it?
Answer:
The rocket also exerts a force on the gas expelled from it.

9th Class Physical Science Textbook Page No. 32

Question 8.
Why does a pole vault jumper land on thick mats of foam?
Answer:
A thick mat of foam reduces the force of impact of the jumper, so that he doesn’t have any damage to his body.

Question 9.
Is it safe to jump on sand rather than a cement floor? Why?
Answer:

• It is safe to jump on sand rather than a cement floor.
• A soft and more cushioned landing surface provides a greater stopping distance because of the longer time taken to stop.

9th Class Physical Science Textbook Page No. 24

Question 10.
You may have seen the trick where a tablecloth is jerked from a table, leaving the dishes that were on the cloth nearly in their original positions.
a) What do you need to perform this successfully?
Answer:
We need a table, a cloth and some massive objects to perform this activity. The performer drag the cloth from the table very skillfully.

b) Which cloth should we use? Is it cloth made of thick cotton or thin silk?
Answer:
We have to use a thin silk cloth to perform this activity.

c) Should the dishes possess large mass or small mass?
Answer:
The dishes must possess large mass. We should not use lighter objects like plastic cups, etc.

d) Is it better to pull the cloth with a large force or pull it with a gentle and steady force?
Answer:
The cloth must be pulled with a gentle force, but with a sudden jerk.

Question 11.
What is the velocity of a small object that has separated from a rocket moving in free space with velocity 10 km/s?
Answer:
When a small object is separated from another object which is moving with a certain velocity. The small object also moves with a velocity equal to that of the object from which it is separated. Hence, the speed of the small object is 10 km/s.

9th Class Physical Science Textbook Page No. 27

Question 12.
Observe the following diagram.

What is the upper limit of weight that a strong man of mass 80 kg can lift as shown in figure?
Answer:
Total force mg = N + T (N = normal force, T = tension)
As the person is standing on the floor, the normal force N = 0.
80 = 0 + T
∴ T = 80
∴ The upper limit of the weight that the person in the figure can lift is 80 kg.

Question 13.
What is the momentum of a ceiling fan when it is rotating?
Answer:
Ceiling fan when it is rotating, possesses angular momentum.
Angular momentum L = mvr or mr²ω.

Question 14.
Is it possible to move in a curved path in the absence of a net force?
Answer:
A body comes into curved path, when centripetal force real force acts on it. Immediately after coming into curved path, an imaginary force which acts away from the centre i.e., centrifugal force comes into existence. These two forces are equal in magnitude and opposite in direction. Hence the net force is zero. So it is possible to move in a curved path in the absence of a net force.

Question 15.
Prove that the tension throughout the string is uniform when the mass of string is considered to be zero.
Answer:

Let a body of mass m is suspended through a string. The weight of the object mg acts downwards. Now tension in the string T = mg + m_sg when m_s is the mass of the string.
Here m_s is considered as zero.
Hence T_A= mg + 0 = mg; T_B = mg ; T_C = mg ; T_D = mg
∴ The tension throughout the string is uniform when the mass of string is considered to be zero.

9th Class Physical Science Textbook Page No. 31

Question 16.
The force exerted by the earth on the ball is 8 N. What is the force on the earth by the ball?
Answer:

• The force exerted by the earth on the ball is 8 N.
• The force exerted by the ball on the earth is – 8 N.

“According to Newton’s third law, if a body A exerted a force p on another body B, the B exerts a force -p on A, the two forces acting along the same line”.

Question 17.
A block is placed on the horizontal surface. There are two forces acting on the block. One, the downward pull of gravity and other a normal force acting on it. Are these forces equal and opposite? Do they form action – reaction pair? Discuss with your friends.
Answer:
These two forces form action-reaction pair.

Question 18.
Why is it difficult for a fire fighter to hold a hose that ejects large amount of water at high speed?
Answer:
A large amount of water with high speed ejects from the hose of a fire engine, produces a large force in forward direction. According to action-reaction, the hose moves back with the same force. But the fire fighter has to resist that reaction force. Hence it becomes very difficult for him.

9th Class Physical Science Textbook Page No. 33

Question 19.
A meteorite burns in the atmosphere before it reaches the earth’s surface. What happens to its momentum?
Answer:
The momentum of the meteorite becomes zero. It doesn’t touch the ground as it burns in the atmosphere. So no mass of the meteorite hits the ground.

Question 20.
As you throw a heavy ball upward, is there any change in the normal force on your feet?
Answer:
The normal force on the feet changes its direction and acts in upward direction. As a result we raise our foot while throwing the ball.

Question 21.
When a coconut falls from a tree and strikes the ground without bouncing. What happens to its momentum?
Answer:
Its momentum doesn’t change but its impact force will be very less because it is not bouncing.

Question 22.
Air bags are used in’the cars for safety. Why?
Answer:
When a car hits another vehicle, the air bags immediately comes in between the persons in the car and the wind shield of the car, to prevent damage to life of passengers.

9th Class Physical Science 2nd Lesson Laws of Motion Activities

Activity – 1

Question 1.
Explain the motion of a pen cap kept on a thick paper ring.
Answer:

1. Make a circular strip from a thick paper.
2. Balance the hoop on the centre of the mouth of the bottle.
3. Now balance a pen cap on the paper hoop aligning it on the centre of the bottle’s mouth.
4. Give the paper hoop a sharp push with your finger as fast as you can.
5. We observe that the pen cap suddenly falls into the bottle.
6. As we push paper hoop, we applied force on the paper hoop. So it changed its state from rest to motion.
7. Pen cap cannot change its state of rest.
8. Due to gravitational force, the pen cap falls into the bottle.

Activity – 2

Question 2.
Explain the motion of the carrom coins hit by a striker.
Answer:

1. Make a stack of carrom coins on the carrom board.
2. Give a sharp hit at the bottom of the stack with striker.
3. We can find that the bottom coin will be removed from the stack.
4. The other coins in the stack will slide down.
5. When we apply force on the bottom coin, the coin will move, due to change in the state of rest.
6. The stack of remaining coins does not fall vertically due to inertia.

Activity – 3

Question 3.
Show that the object with larger mass has greater inertia.
Answer:

1. Take two rectangular wooden blocks with different masses.
2. Place them on a straight line drawn on a floor.
3. Give the same push at the same time to both the blocks with the help of a wooden scale.
4. We observe that the block with small mass will accelerate more and goes farther.
5. The block with large mass accelerates less and moves shorter, due to high inertia.
6. This shows that the bodies of higher mass have high inertia.

Activity – 4

Question 4.
Show that the larger the net force greater the acceleration.
Answer:

1. Gently push a block of ice on a smooth surface and observe how the object speeds up, in other words how it accelerates.
2. Now increase the net force and observe change in its speed.

Observation : The acceleration increases.

Conclusion : If the net force is larger, then the accelerations greater.

Activity – 5

Question 5.
Show that the larger the mass smaller the acceleration.
Answer:

1. Apply a force on an ice block.
2. It undergoes some acceleration.
3. Now take a block of ice with greater mass.
4. Then apply almost the same force on the ice block which has greater mass.

Observations :

1. In both cases the object accelerates.
2. But we can observe in the second case, it will not speed up as quickly as before.

Conclusion : If the mass is larger, then the acceleration is smaller.

Activity – 6

Question 6.
Pulling two spring balances.
Answer:
Let’s take two spring balances of equal calibrations. Connect the two spring balances as shown in figure. Pull the spring balances in opposite directions as shown in figure.

Observation :
There is no change in the reading of spring balances. We are not able to make the spring balances to show different readings by pulling them simultaneously in opposite directions.

Conclusion :
According to third law of motion, when an object exerts a force on the other object, the second object also exerts a force on the first one which is equal in magnitude but opposite in direction.

The two opposing forces are known as action and reaction pair. Newton’s third law explains what happens when one object exerts a force on another object.

Activity – 7

Question 7.
Describe the preparation of a balloon rocket. What is the principle involved in it?
Answer:

Preparation of a balloon rocket :

1. Inflate a balloon and press its neck with fingers to prevent air escaping from it.
2. Pass a thread through a straw and tape the balloon on the straw.
3. Hold one end of the thread and ask your friend to hold the other end of the thread.
4. Now release air from balloon by removing fingers from the neck of the balloon.
5. The balloon moves like a rocket towards the other end

Principle involved in it:

1. Newton’s third law of motion is the principle.
2. As the air in the balloon moves backward, the balloon moves forward.

Lab Activity

Question 8.
Describe an activity to study the action and reaction forces acting on two different objects.
Answer:
Aim : To show the action and reaction forces acting on two different objects.

Material required : Test tube, rubber cork cap, Bunsen burner, laboratory stand and thread.

Procedure :

1. Take a test tube and put a small amount of water in it.
2. Place a rubber cork cap at its mouth to close it.
3. Now suspend the test tube horizontally to a stand with the help of two strings.
4. Heat the test tube with a bunsen burner until water vapourize and the rubber cork cap blows out.

Observations :

1. Observe the movement of test tube when cork cap blows out.
2. As the cork cap blows out in forward direction, the test tube recoils back.
3. We can observe the velocities of cork cap and recoil of test tube to be same.

Activity – 8

Question 9.
Show that the impulse will be less on a soft and cushioned surface.
Answer:

• Take two eggs.
• Drop them from a certain height, so that one egg falls on a concrete floor and the other on a cushioned pillow.
• We observe that the egg that falls on a concrete floor will break.

• The reason is large force acts on the egg for short interval of time.
  ∆p = F_net∆t
• The egg which falls on a cushioned pillow doesn’t break, because a smaller force acts on the egg for a longer time.
  ∆p= F_net ∆t
• This shows that the impulse (∆P) will be less on a soft and cushioned surface.

Note : Even if the ∆p is the same in both cases, the magnitude of the net force (F_{net</sub) acting on the egg determines whether the egg will break or not.}

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 10 Prices and Cost of Living.

AP State Syllabus 9th Class Social Studies Important Questions 10th Lesson Prices and Cost of Living

9th Class Social 10th Lesson Prices and Cost of Living 2 Marks Important Questions and Answers

Question 1.
“Public distribution system is one of the government programme to eradicate poverty. But one aspect of this programme is that it is not reaching the eligible people”.
Suggest the measures for better implementation of public distribution system? (SA-III : 2015-16)
Answer:
The following measures should be taken to improve the present Public Distribution System (PDS).

1. Implementation of measures such as door step delivery of food grains.
2. Improving viability of fair price shop operations.
3. Greater monitoring and vigilance.
4. Improve food grains off take.
5. Correct identification of beneficiaries.
6. Smart system communication like information provided to consumers by SMS about rations.

9th Class Social 10th Lesson Prices and Cost of Living Important Questions and Answers

Question 1.
What is inflation? Explain.
Answer:

• Continuous rise in prices of goods is known as inflation.
• The value of money also decreases with inflation.
• With more money also we could buy less goods only.
• This in turn increases the expenditure.
• Thus lower inflation is always better.

Question 2.
Who do you think are not affected by rising prices?
Answer:

• Not everyone is affected by rising prices.
• Extremely rich persons are not affected by rising prices.
• People those, who are working in corporate sector do not get affected by rising prices.

Question 3.
What is a price index? How is it useful?
Answer:

• Change in price is measured with the help of a statistical device referred to as price index.
• Change in prices of one good does not affect all goods and services in the same way.
• So we use index numbers of prices to measure the overall change in prices.
• Index numbers tell us about changes in the sum total of a set of items over time.

Question 4.
Read the following passage and answer the questions given below.

i) Why does the government fix prices under APM?
Answer:
For preventing hoarding and keeping the prices of essential commodities within reasonable levels and to facilitate their availability, the government fixes the prices.

ii) Which goods are subsidised by the government?
Answer:
Goods such as kerosene, diesel, liquid petroleum gas, compressed natural gas, piped natural gas are examples of goods which are partly or solely subsidised by the government.

Question 5.
Estimating Consumer Price Index
This is an example of how CPI can be constructed. Let us assume that your family buys rice, onions, dal, and gas cylinder.

1) How much more do we have to pay compared to last month?
Answer:
The expenditure has been increased by Rs. 350.

2) What is the percentage of increase?
Answer:
Percentage = \(\frac{350}{1500}\) × 100 = 23.3%

Question 6.
What is a budget? How does the government meet the deficit in the budget?
Answer:

• Budget is the financial statement which shows the anticipated incomes and expenditure of a family, or an institution or a state or any central government.
• When expenditures are more than incomes, then it is called a deficit budget.
• The government levies taxes on people to meet the deficit.

Question 7.
Nowadays there is rise in prices, why do people appear agitated and worried with it?
Answer:

• Nowadays rise in prices is common.
• People are always worried about rise in prices.
• It affects their consumption and they have to pay more for everything.
• Petrol prices increase, bus and auto fares increase, prices of groceries, vegetables, and milk increase, doctors fee increase and soon.
• Thus people always appear to be agitated about the rise in prices.

Question 8.
Prices of agricultural goods/products are volatile. What initiatives are taken by government to help farmers?
Answer:

• Government regulates traders in agricultural products/goods.
• It procures through Food Corporation of India, rice and wheat from farmers using Minimum Support Price (MSP).
• Traders also need to pay MSP.
• It also fixes price for sugarcane procured to make sugar in cooperative sugar mills.
• In these ways government try to regulate prices of agricultural products/goods in the market.

Question 9.
Why should the government give subsidies? On which items generally subsidies are given?
Answer:

• The government generally gives subsidies to keep the prices of essential commodities within the resonable levels.
• Goods such as kerosene, diesel, liquid petroleum gas, compressed natural gas, and piped natural gas are examples of goods whose prices are partly or solely subsidised by the government.

Question 10.
What measures are taken by government to control prices or reduce inflation?
Answer:

• To control unscrupulous rise in prices of essential goods in market, government supplies food items at subsidised prices through Public Distribution System.
• For preventing hoarding and keeping prices at reasonable level, government fixes prices of commodities like kerosene, diesel, gas, etc. through various laws.
• When there is price rise, RBI reduces the money circulation in the economy.
• Then it poses taxes on high-income groups and on many consumer goods.
• Government also uses Import – Export policy to regulate the prices of essential goods.
• Government also use legal mechanism whenever traders create shortage by hoarding.

SCERT AP Board 9th Class Social Solutions 2nd Lesson The Natural Realms of the Earth Textbook Questions and Answers.

AP State Syllabus 9th Class Social Studies Solutions 2nd Lesson The Natural Realms of the Earth

9th Class Social Studies 2nd Lesson The Natural Realms of the Earth Textbook Questions and Answers

Improve Your Learning

Question 1.
Fill in the blanks.
a) Hydrosphere is related to …………………….. .
b) Lithosphere is related to …………………….. .
c) Atmosphere is related to …………………….. .
d) Biosphere is related to …………………….. .
Answer:
a) water mass
b) land mass
c) air mass
d) life

Question 2.
Find the odd one out in the context of lithosphere and give reasons for your choice.
Byson gorge; Grand Canyon; Ozone; Thar desert.
Answer:
Out of these four ozone is the odd one.
Reasons:

1. Byson gorge and Grand canyon are hilly areas.
2. Rivers flow through them.
3. Plants and trees are present there.
4. Thar desert is a vast sand desert, with no water. It has thorny bushes and some kinds of desert plantations.
5. Above three are landforms.
6. But Ozone is an inorganic molecule with the chemical formula 03. It is a pale blue gas with a distinctively pungent smell. Ozone’s 03 formula was determined in 1865.

Question 3.
How is the Lithosphere formed?
Answer:

• The solid crust or the hard top part of the earth is called lithosphere.
• The crust is made up of rocks and minerals and covered with a thick layer of soil.
• It is uneven and has high mountains, plateaus, plains, and very deep basins.
• Many of these features are shaped by internal and external processes.
• The slow movements inside the earth lead to the formation of the crust.
• The sudden movements can damage and lead to changes in landforms.
• The processes originating from the depths of the earth like earthquakes and the volcanic eruptions play important role in shaping the surface of the earth.
• The external sources like wind, water, glaciers, and waves also play prominent role in shaping the lithosphere.

Question 4.
How are the continental plates formed and how are they eventually destroyed?
Answer:

• In the beginning, probably all continents were held together.
• Later the earth’s lithosphere is broken up into several pieces, just like the pieces of a large jigsaw puzzle and thus continental plates formed.
• These pieces, on which all the continents and oceans are actually situated, are called “Plates”.
• They float on soft layer of the mantle.
• There are about seven major plates and several minor plates on the earth.
• As the plates move, they push, pull, slide, rise, sink, bend and break.
• Sometimes one plate meets another, the incoming plate dips under the stable plate.
• In fact the incoming plate actually goes into the mantle of the earth and becomes molten due to the heat of the mantle.
• That is how some plates are eventually destroyed.

Question 5.
List out the landforms formed due to the river work. (AS1)
Answer:
Many landforms are formed due to the work of the river. They are
1. V – shaped valley:
The flow of a river is very swift as it descends the steep slopes and it exerts a great force in cutting the mountain vertically. As a result a deep valley develops, narrow at the bottom and wide at the top. This is called V – shaped valley.

2. Gorge:
Where the rocks are very hard, the river cuts a narrow valley with steep sides called Gorges.

3. Canyon:
A deep valley with steep like slopes and is wider at its top than at the bottom is called a Canyon.

4. A plunge pool:
The water falls with great force and dig out the rock beneath to form a plunge pool.

5. Plain:
When the river is in floods it cuts the soil and when it is not in flood it deposits silt and thus forms vast flood plains.

6. Meanders:
As a result of the deposition by floods the river bed becomes too high, the river constantly changes its course and cuts new path and forms gentle snake like meanders.

7. Ox-bow lakes:
Due to the deposition along the sides of the meanders, the ends of the meander loop comes closer and closer. In the course of time the meander loop cuts off from the river and forms a cut off lake which is called ox-bow lake.

8. Delta:
When a river reaches the sea, the fine material is deposited at its mouth forming a delta (∆).

9. Ozone:
Ozone is an inorganic molecule with the chemical formula 03. It is a pale blue gas with a distinctively pungent smell. Ozone’s 03 formula was determined in 1865.

Question 6.
Create a table as given below and fill information. And write a small paragraph to explain the similarities and differences you can think of in the context of earth’s external changes, (if there is no information available in the text, leave those columns blank)

Answer:
Wind:
Wind takes many forms and carries away the surface of the land in the higher places.

Water :

1. Water reacts with the chemicals of the rocks and further weakens the rock.
   Water acts as moving agent of the earth.

Glacier :

1. The ice on these glaciers melt throughout the year and flows to low areas as rivers and streams.
2. They also erode, transport and deposit rock materials.

Two forces, weathering and erosion, are constantly at work building up and moving rocks making up the earth’s crust.

Weathering causes rocks to fragment, crack, crumble, or break down physically and chemically.

Erosion loosens and carries away the rock debris formed by weathering. Over time these two forces, working together, change the shape of the land.

Question 7.
Why are Glaciers not found in your surroundings?
Answer:
Glaciers are most commonly found above snow line i.e., regions of high snow fall in winter and cool temperatures in summer. These conditions allow more snow to accumulate on the glacier in the winter that will melt in the summer. This is why most glaciers are found either in mountainous areas or the polar regions.

We are in the state of Andhra Pradesh. It is a semi-arid area and has a predominantly hot and dry climate. Summers start in March, and peak in May with average high temperatures in the 42°C range. A dry, mild winter starts in late November and lasts until early February with little humidity and average temperatures in the 22°C – 23°C range. In such hot and dry conditions glaciers are not formed. So we cannot find glaciers in our surroundings.

Question 8.
How are Beaches formed and name some Beaches?
Answer:
Formation of Beaches:

1. Sea water contains sediments like sand, pebbles, etc.
2. Beaches form as waves deposit these sediment on the shore.
3. The wind pushes these sediments on the shore and inland.
4. This creates an area of sand particles finally form a beach.

Names of some beaches :

1. Diu Beach
2. Manori Beach, Mumbai
3. Versova Beach, Mumbai
4. Mivamar Beach, Panaji
5. Karwar Beach, Karnataka
6. Fort Kochi, Cochin
7. Kovalam Beach, Trivandrum
8. Marina Beach, Chennai
9. R.K. Beach, Visakhapatnam
10. Chandipur Beach, Odisha.

Question 9.
How is the human lifestyle responsible for extension of deserts?
Answer:

• Desertification can be considered as a set of biological, chemical, and physical processes which converge to create desert-like conditions.
• Desertification is a social problem involving people at all stages as a cause and as victims.
• The anthropogenic (human) causes of desertification are over cultivation, over grazing, deforestation and poor irrigation practices.
• These factors are fuelled by local forces such as poverty and population pressure.
• Increase in temperature leads to drying out of water and it further causes to expansion of deserts.
• Mismanagement of dry land ecosystems by humans can cause desertification.
• Poor land use and overgrazing are significant factors for the expansion of deserts.
• Thus activities of human beings lead to the extension of deserts.

Question 10.
Find out the order of the landforms for the following.

Answer:

Question 11.
Draw the map of world plates by observing map 2.
Answer:

Question 12.
Read the para under the title ‘Erosion’ on page 20 and comment on it.

Answer:
Erosion is the process by which soil and rock are removed from the earth’s surface by exogenic processes such as wind or water flow, and then transported andsdeposited on their locations while erosion is a natural process. Human activities have increased by 10 – 40 times the rate of which erosion is occuring globally.

Question 13.
Collect newspaper or magazine articles and news on earthquakes and volcanoes.
Prepare an illustrated file on these – how do they happen and how they affect human life.
Answer:
Student’s activity.
Ex: Earthquakes:
The earth’s surface is formed of massive slabs of rock called plates. These are called tectonic plates, are always moving. Sometimes they just slide past one another. At another time they actually collide with one another. Plate movements cause the build up of tremendous quantities of energy in the rock. When the energy is released, it produces vibrations that travel through the rock, leading to earthquakes. During earthquakes, faults, or giant cracks, are produced by the pressure of moving rocks.

Volcanoes:
Deep within the earth it is so hot that some rocks slowly melt and become a thick flowing substance called magma. Because it is lighter than the solid rock around it, magma rises and collects in magma chambers. Eventually some of the magma pushes through vents and fissures in the earth’s surface. Then a volcanic eruption occurs.

Their effect on human life :

1. Major earthquakes and volcano eruption can affect human life.
2. Roads can be damaged and delivery of food can be disrupted.
3. Clean, drinking water may not be available.
4. Sewer system may leave, causing diseases.
5. Gas line could leak, causing health issue.
6. All the surroundings can get covered with ash.
7. Communication system fails.
8. They destroy property and threaten human lives.

9th Class Social Studies 2nd Lesson The Natural Realms of the Earth InText Questions and Answers

Question 1.
Why do you think the rock is harder inside than outside? (Text Book Page No. 20)
Answer:

• The gradual disintegration of rocks is caused by atmosphere forces.
• The rocks when exposed to heat expand and contract when cooled down.
• As surface rock contracts and expands and contracts again, it gradually becomes brittle and begins to break down.
• Water reacts with the chemicals in the rock and further weakens it.
• These processes by which the rocks are weakened and broken are called ‘weathering’.
• It is easier to chip small pieces of rock from the outer layer rather than from the core of the rock.
• Thus we can say the rocks are harder inside than outside.

Question 2.
Expalin how are the waterfalls are useful. (Text Book Page No. 22)
Answer:

• The most noted advantage of waterfalls is their ability to produce hydroelectric power.
• As it descends the steep slopes the waterfall exerts a great force and cuts mountains vertically and forms V-shaped valleys, gorges and canyons.
• These attract many tourists throughout the world and earn a lot of foreign exchange.
• Waterfalls put oxygen into the water which first helps the fish breathe well.

Question 3.
Can you discuss in the class how the following human actions impact the lithosphere?
i) Mining
ii) Building cities with bricks and cement
iii) Agriculture
iv) Dams (Text Book Page No. 25)
(OR)
‘Human actions like mining, building cities with bricks and cement, agriculture and dams are impacting the lithosphere’ – Comment on it. Mra
Answer:
i) Impact of mining on lithosphere :

• Mining disturbs and removes the rocks, ores and minerals in the geosphere.
• It leaves huge gaping holes in the earth.
• The mine tailings are pulled up in large mounds on the surface of the geosphere.
• Subsidence is an effect that occurs above a deep mine.
• The deep mines cause redistribution of the existing tectonic stress field disturbed by the excavation process.
• High stresses exist inside tectonic plates and they are sensitive to any perturbations.
• In case of mining the mass removal causes fault zones and eventually earthquakes.

ii) Impact of building cities with brick and cement on lithosphere:
Constructing buildings with cement and bricks has a lot of negative effects.

• Concrete used to create hard surfaces causes to surface turn off and it can cause heavy soil erosion.
• Constructing the buildings with cement, bricks and concrete have different thermal and hydrological properties. These cause the surface absorbs and stores heat and water.

iii) Impact of agriculture on lithosphere:
Man has been trying to manipulate more and more of nature and exploit this natural resource by the unscientific practice of agriculture.

• Agriculture causes the depletion of underground acquifiers through overdrafting.
• Under irrigation gives poor soil salinity control which leads to increase soil salinity with consequent build up of toxic salts on soil surface.
• Wide use of agricultural chemicals causes soil pollution.

iv) Impact of dams on lithosphere :

• As a result of dam construction and holding of sediments in reservoirs sediment feeding of down stream channel or shore beaches is prevented.
• Corrosions may occur.
• Rare archaeological and historical places with their exceptional beauties disppear after lying under the reservoir.
• Earthquakes and volcanic activity can be induced by the weight of the reservoir on nearby faulty lines.
• Soil erosion of silt deposited at the edges of reservoirs can seriously damage surrounding vegetation and farmland by sand blow.

Question 4.
Write an imaginary description of the damages that occur due to volcanic eruption in an area. (Text Book Page No. 19)
Answer:

• Volcanic eruption can cause earthquakes, fast floods, mudslides and rock falls.
• Lava can travel very far and burn, bury or damage anything in its path including people, houses and trees.
• The large amount of dust and ash can cause roofs to fall, makes it hard to breathe and is normally very smelly.
• The ground around volcano is not secure and can cause big earthquakes.
• Big volcanic eruptions can change the weather around the world.
• Ash clouds float very high in the air and can cause snow and frost in the summer in a lot of countries.

Question 5.
Compare the Loess Plains with a Delta. What similarities and differences do you see between them? (Text Book Page No. 25)
Answer:
Similarities between Loess Plains and Deltas :

1. Both are the deposits of erosional fine materials on plains.
2. Both loess plains and deltas are fertile lands.

Differences between Loess Plains and Deltas:

1. While loess plains are formed with fine dust blown beyond the deserts, the deltas are formed with fine alluvial material transported by the rivers.
2. While loess plains are formed in the neighbouring lands of the deserts, the deltas are formed at the mouths of the rivers.
3. While loess are fine loam, rich in lime, very coherent and extremely porous, the deltas consist of clayey alluvial soils with a mixture of organic material.
4. While deltas are formed by the action of rivers, the loess plains are formed by the action of winds.

Question 6.
Geologists have found fossils of sea animals on the Himalayas. Some of these are actually worshipped in many homes as ’Salagramas’. How do you think are these^ossil^here on the Himalayas? (Text Book Page No. 17)
Answer:

• The Himalayas are formed by the collision of the Indian and Eurasian land masses which were originally separate.
• This collision uplifts mountains.
• From around 200 million years ago the area between the two separate land masses was covered by the Tethys sea, which was filling with sediments and had sea creatures which left fossils in the sedimentary rocks formed there.
• So the fossils found in the Himalayas are those formed in the ancient sea bed of the Tethys sea, now exposed and pushed up to form mountains.
• Salagramas are usually black coloured spherical fossils found in the sacred river Gandaki.
• The name salagrama refers to the name of the village on the bank of the Gandaki, where the holy stones are picked up.
• Hindus consider these salagramas as an iconic representation of Vishnu and worship these salagramas.

Question 7.
Collect information about the waterfalls in Andhra Pradesh. (Text Book Page No. 22)
Answer:
Waterfalls of Telangana :

1. Ethipothala falls, near Nagarjuna Sagar Dam.
2. Katiki waterfalls – Visakhapatnam district
3. Kailasakona falls – Chittoor district
4. Mallelatheertham – Nallamala forest, Kurnool district
5. Penchalakona falls – Nellore district
6. Rampachodavaram – East Godavari district
7. Talakona falls – Chittoor district
8. Ubbalamadugu or Tada falls – Chittoor district

Question 8.
Collect some of the pictures of waterfalls. (Text Book Page No. 22)
Answer:
Pictures of famous waterfalls :

Question 9.
Gorges are suitable for construction of dams- can you tell why this is so? (Text Book Page No. 21)
Answer:

• Gorges are narrow valleys with steep sides.
• A gorge is almost equal in width at its top as well as its bottom.
• They are suitable for the construction of massive reservoirs.
• The natural valleys formed by the gorges are built up with hard rock.
• The valleys with its steep sides, extensive rocky floors form the natural reservoirs for the dams.
• Constructing the dams at gorges is less expensive because a little concrete work is needed to form the reservoirs.
• In these vast and massive reservoirs a lot of water can be stored.
• Gorges are flood proof. They prevent floods.
• The waterfalls that falls down from great heights into the gorges can rotate large turbines and generate hydroelectricity in large quantities.
• Thus gorges are suitable for the construction of dams.

Question 10.
You have read about mining of minerals like baryte or coal. In what ways do you think does mining affects the lithosphere, hydrosphere and atmosphere? (Text Book Page No. 14)
Answer:

• Mining disturbs and removes the rocks, ores and minerals in the lithosphere leaving huge gaping holes in the earth.
• The mine tailings are piled up in large mounds on the surface of the earth.
• Mining waste when washed into the water ways pollutes the hydrosphere.
• Mining causes air pollution to the atmosphere in several ways.
• The mine might also release poisonous gases that were trapped below the surface.
• Mining affects the biosphere by affecting the other three spheres in an indirect way.

Question 11.
Human beings consume a lot of medicines like anti-biotics to cure sickness. How do you think does it affect the lithosphere, hydrosphere and biosphere? (Text Book Page No. 14)
Answer:

• More than 10,000 tonnes of anti biotics are consumed in Europe each year.
• 30%-60% of them passthrough animals and humans unchanged and reach the ocean.
• These antibiotics can affect the marine ecosystems over a long period, with detrimental effects on natural marine communities of bacteria.
• The presence of antibiotics in the marine environment is worrying as it can reach to humans through the consumption of sea food and fish.
• The marine sediments affected by the antibiotics metabolise both nitrogen and carbon which are linked to both eutrophication and climate problems.

Question 12.
What are the dangers of living on the flood plains? (Text Book Page No. 23)
Answer:

• Flood plains are flood prone areas.
• Massive damage can occur during floods in flood plains.
• Homes, automobiles, buildings, historical monuments, graves, sewer systems, bridges and countless other infrastructure can be destroyed.
• Road ways often suffer. High flooding often claims the lives of drowning victims.
• In flood plains during floods there will be lack of clean drinking water which causes illness and epidemics to spread.
• Thus there are a lot of dangers of living on the flood plains.

Question 13.
Locate the Himalayas, Andes and Rockies mountains. Why were they formed in those locations? Suggest reasons. (Text Book Page No. 17)
Answer:

1) Himalayas
2) Rockies mountains
3) Andes mountains

Reasons:

1. Fold mountains are mountains formed from the folding of the earth’s crust.
2. The Himalayas, the Andes and the Rockies are fold mountains.
3. These fold mountains are formed when two plates move together.
4. The Himalayan mountains were formed by the process of Indian plate pushing the Eurasian plate.
5. The forces of plate tectonics are responsible for the formation of Andes.
6. The Nazce plate and a part of the Antarctica plate have been subducting beneath the South American plate.
7. The Rockey mountains took shape during an intense period of plate tectonic activity that resulted in much of the rugged landscape of the Western North America.
8. The Laramide Orogeny was responsible for raising the Rocky mountains.

Question 14.
You may have noticed that many of the ‘scientific’ terms use Greek words. Why do you think do they use Greek words? Discuss with your teacher. (Text Book Page No. 14)
Answer:
In his communication a scientist is mainly concerned with exact and logical expression of that which he wishes to pass on to another. His purpose is to inform as clearly as possible. Each of his words must have a precise meaning and one meaning only so that there is no risk of confusion or ambiguity. The meanings of many ordinary words of our language are not single and precise. The use of words which are ‘set apart’ from everyday life also enables the scientist to avoid evoking irrelevant and distorting associations.

In addition to precision of meaning and freedom from associations most scientific words by their form and structure they reveal something of their meanings. Many scientific words are built from simpler word-elements usually of Greek origin. Some words are self-explanatory if the Greek roots are known.

Scientific language to be efficient must be universally intelligible. The classical language Greek is so fundamental to the civilised world. The words constructed from this language can easily be learnt to be translated.

So scientific terms use Greek words.

Question 14.
Are all rocks on the earth formed in the mid-ocean ridges? (Text Book Page No. 17)
Answer:
No. All the rocks on the earth are not formed in the mid-ocean ridges. Only ocean rocks or crust are formed of the mid-ocean ridges. These are formed by lava rising up from the mantle. The eruptions on the ridges create new ocean floor made of basalt rocks, which then spreads laterally from the ridge. The first order landforms such as oceans and continents are formed at the time when the hot earth was cooling. While the earth’s interior continued to cool, it contracted and the outer crust wrinkled forming ridges i.e., mountains and basins i.e., oceans. The second order landforms such as plains, plateaus and mountains are formed as a result of the internal processes of the earth. The third order landforms such as carved mountains, valleys, deltas, sand dunes are formed as a result of the shaping of the land forms by wind, water.

Question 15.
Why do you think we don’t feel any of these mighty changes taking place on the earth? Is it because they don’t affect us? Do you think these changes affect us at all? (Text Book Page No. 17)
Answer:

• Two kinds of changes take place in the Lithosphere – first the very slow movements leading to the formation of the crust, movement of the continental plates and their eventual return to the mantle.
• Since these geophysical changes occur over thousands and even millions of years we don’t feel any of these changes.
• Secondly the sudden and dramatic eruption of volcanoes and earthquakes.
• The sudden movements can be destructive and cause much damage. At the same time they also lead to changes in landforms.

Question 16.
Compare the action of the river in the mountains and in the plains. In what ways are they similar and different?
Answer:
Similarities :

1. They carry something when they flow across the two landforms.
2. They have streams in both the areas.
3. They change the surface of the earth.

Differences

From the mountains to delta, a river does not just flow – it changes the surface of the earth.

It cuts rocks, moves boulders, and deposits sediments.
It constantly attempts to carve away all the mountains in its path.

The goal of the river is to create a wide, flat valley which it can flow smoothly towards the ocean.

That is the relation between the mountains and plains.

Question 17.
Why is a flood plain more suited to human habitation compared to mountains? (Text Book Page No. 23)
Answer:
Disadvantages of mountains :

1. High elevation on mountains produces colder climates than at sea level.
2. These colder climates strongly affect the human habitation.
3. Climate of mountains to be used less for agriculture.
4. Abundant water supply.
5. Fertile land – rich for farming and agriculture.
6. Easy to develop than hilly regions.
7. Flood water can be stored temporarily.
8. Many civilizations are flourished on the banks of the rivers.
   These are all more suited to human habitation compared to mountains.

Question 18.
Recall the life of people living in the hills or flood plains that you may have read of. (Text Book Page No. 23)
Answer:
Bison hills are spread in both Bhadradri Kothagudem and W. Godavari districts along either banks of the river Godavari. Many tribal communities live in the hill tracts of this region with their own special life.

These tribals live in small habitations – about 5 to 10 hutments in one place. The habitations are far from each other.

Konda Reddys grow crops in a distinct way called Podu. When rains arrive in June they dibble seeds with the help of digging seeds.

Except for a few months during and after harvest, Konda Reddy women and children are engaged in collection of edible forest produce for subsistence.

There are no rivers or wells in this area. They fetch water from natural springs.

These hill tribes are very few in number but they follow a pattern of life which is very ancient.

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 5 Biosphere.

AP State Syllabus 9th Class Social Studies Important Questions 5th Lesson Biosphere

9th Class Social 5th Lesson Biosphere 1 Mark Important Questions and Answers

Question 1.
Prepare two slogans to support the protection of the environment. (SA-III : 2015-16)
(0R)
Write two slogans on the prevention of environmental pollution.
Answer:

• “Environment is life, pollution is death.”
• Live green, love green, be green.
• Hate pollution, love environment.

Question 2.
Write any two programs on the prevention of environmental pollution to aware people. (SA-II : 2017-18)
Answer:

• Explain to the people who are living in the villages and towns through documentary films about protection of environment.
• Through folk songs and playlets create awareness about protection of environment.

Question 3.
Make some slogans on conservation of forests. (SA-II : 2016-17)
Answer:

• Plant a tree, so that next generation can get air for free.
• Take care of the trees, they will take care of you.
• If you cut a tree, you kill a life.

Question 4.
As a student what activities would you take up to reduce global warming? (SA-I : 2018-19)
Answer:

• Increase the greenery in open and empty places.
• Use the public transport for short distant areas.

Question 5.
Write any two causes for Global warming. (SA-II : 2018-19)
Answer:

1. Deforestation.
2. Emission of green house gases from industries.

Question 6.
Mention any two features of Tropical Deciduous Forests. (SA-I : 2019-20)
Answer:
Features of Tropical Deciduous Forests :

1. Trees shed their leaves in the dry season to conserve water.
2. The hardwood trees found in these forests are sal, teak, neem and shisham.

9th Class Social 5th Lesson Biosphere 2 Marks Important Questions and Answers

Question 1.
How can we protect our forests? (SA-II : 2016-17)
(OR)
Suggest any two ways to protect forests. (SA-II : 2018-19)
Answer:
There are various methods of conserving a forest.

1. The main and important method is declaring the forest area is a reserved forest area due to which it cannot be used for commercial use.
2. By appointing a forest officer who looks on the development of the forest and also looks for the misuse of the forest which he reports to the administration.
3. Afforestation method.
4. Encouraging forest community to protect their own flora.

Question 2.
List 4 ways in which faster depletion of natural resources can be reduced. (SA-I : 2019-20)
Answer:

1. Planting trees in Industrial places and besides roads.
2. Ban on cutting forests.
3. Industrialization should be in the limit, should not be harmful to environment.
4. Mining of various minerals should be in the control of government.

9th Class Social 5th Lesson Biosphere 4 Marks Important Questions and Answers

Question 1.
“Industrialisation, rapid population growth and urbanisation lead to unprecedented exploitation of natural resources like minerals, forests, soil, water, air, etc”.
‘Protection of non renewable natural resources is must’. Comment. (SA-III : 2016-16)
Answer:

• The production of coal, electricity and natural gas is not adequate to all as per our present requirements. It is important to use economically the available resources and compensate the scarcity with alternative which society faces today. As they are scarce and expensive it is better move towards non-conventional sources.
• Non-renewable energy resources like coal, oil and natural gas cannot be recycled or reused.
• Forest are ho/nes for a number of wild animals. They protect water loss from top soil and thus prevention formation of deserts.
• If rainfall is less the surface and ground water will be low so encourage recycling of water and percolating of more rain water.

Question 2.
When human beings began to practise agriculture and animal husbandry, they began to change the environment even more. The building of cities and the use of metals like bronze and iron further change human interaction with the environment.
Q: Is development causes to environment pollution? “comment on it. (SA-II : 2016-17)
Answer:
1. Establishment of Industries :
Industries are the important to economic development of any country but they release green house gases causes to environment pollution.
Ex : Transportation of petrol through pipe lines, if there is a leak in the pipe line, soil will automatically be polluted.

2. Transportation :
Each and every person has a own vehicle which is run by petrel, diesel or gas. This is the significance of development of our country. At the same time pollution will arise with these vehicles.

3. Agricultural Activities :
To increase production in foodgrains we are following green revolution methods. But these methods are responsible for the contamination of water and soil.

4. Trading Activities :
Trading activities including the production and exchange of goods and services. Concerning goods, pollution can be caused by packaging (which often involves the use of plastic which is made from fossil fuels) or transport, mainly.

Question 3.
Observe the given table and answer the following questions. (SA-II : 2016-17)

Answer the following questions.
1. What type of forests mostly spread in India?
2. Which types of forests are there in Himalayas?
3. Which type of trees grown in Tropical Evergreen forests?
4. Teak, Neem trees are grown in which type of forests?
Answer:

1. Tropical Deciduous Forest
2. Coniferous Forests.
3. Rosewood, Ebony, Mahogany (etc.)
4. Teak, Neem trees are grown in Tropical Decidious Forests.

Question 4.
All living and non-living things on the earth are in one way or the other connected to each other. Changes affecting one, in due time affect all others too. Explain this statement with examples. (SA-I : 2019-20)
Answer:
Yes, All living and non-living things on the earth are in one way or the other connected to each other, changes affecting one, in due time affects all others too.

Example 1 :
Vultures feed upon dead animals like cattle. However, people started noticing that Vultures have virtually disappeared and are sighted very rarely. Finally, they found that farmers use a particular chemical called Diclofenac to treat cattle. When the cattle die their flesh retains. This Chemical when their flesh is consumed by vultures, diclofenac leads to kidney failure in them and they die within a week or so. In this way vultures have come very close to extinction.

Example 2 :
The disturbance caused by mixing of some poisonous substances in air or water or soil the metals.like mercury are consumed by micro-organisms in water and in turn become the food of a large number of fishes when human beings consume these fishes they too absorb quantities of mercury that are detrimental to their health.

9th Class Social 5th Lesson Biosphere Important Questions and Answers

Question 1.
What is Global warming ? What are the reasons for global warming?
Answer:
Global warming :

1. Global warming is the increase of Earth’s average surface temperature due to effect of greenhouse gases such as carbon dioxide emissions from burning fossil fuels.
2. In Global warming the heat received by the earth is trapped into the atmosphere and is not released into the sky.

Reasons for global warming :

• Release of carbon dioxide into the atmosphere by power plants by burning the fossil fuels.
• Release of carbon dioxide into the atmosphere by burning gasoline by automobiles.
• Methane emissions from animals agriculture.
• Deforestation especially tropical forests for wood, pulp and farmland.
• Increase in usage of chemical fertilizers on croplands.

Question 2.
What is Greenhouse effect?
Answer:

• The earth radiates whatever heat it receives from the sun into the sky.
• The greenhouse gases such as carbon dioxide, methane, chloro flouro carbons trap the heat reflected by the earth into the sky and thus maintain a constant surface temperature.
• This mechanism is known as Greenhouse effect.

Question 3.
Write the names of major Greenhouse gases and their sources.
Answer:

Question 4.
How do you think acid rains will affect natural vegetation and crops?
Answer:

1. A rain or any other form of precipitation that is usually acidic meaning that it possesses elevated levels of hydrogen ions.
2. Acid rain is caused by emissions of sulphur dioxide, nitrogen oxide which react with the water molecules in the atmosphere to produce acid rains.
3. The affect of acid rains on natural vegetation and crops :
   a) The roots are damaged by acidic rainfall, causing the growth of the plant to be stunted or even in its death.
   b) Nutrients present in the soils are destroyed by the acidity.
   c) Useful micro organisms which release nutrients from decaying organic matter into the soil are killed off.
   d) The acid rains damage the waxy layer of the leaves and make the plants vulnerable to diseases.
   e) Plants germination and reproduction is also inhibited by the effects of acid rain.

Question 5.
How does the release of mercury into the streams and rivers affect us?
Answer:

• Mercury released into water is consumed by micro organisms in water and in turn become the food of a large number of fishes.
  When human beings consume these fishes they too absorb quantities of mercury that are detrimental to human health.

Question 6.
What is meant by ‘Biosphere’?
Answer:
According to many geographers, life itself constitutes a separate sphere called ‘biosphere’.

Question 7.
Into how many categories is the natural vegetation classified? What are they?
Answer:
Natural vegetation is generally classified into three broad categories. They are forests, grasslands, and shrubs.

Question 8.
Write the names of trees and animals in the coniferous forests.
Answer:
Chir, pine, cedar are the important trees in coniferous forests. Silver fox, mink, polar bear are the animals commonly found here.

Question 9.
Write the reason of acid rains.
Answer:
Acid rains are caused by the mingling of acidic particles of the atmosphere with the rain by increasing the acid content of rain water.

Question 10.
How is mediterranean climate and vegetation are different?
Answer:

• Mediterranean regions are marked for hot dry summers and mild rainy winters.
• Citrus fruits such as oranges, figs, olives and grapes are commonly cultivated here.
• Vegetation here adapt themselves to dry summers with the help of thick bark and wax coated leaves, which help them reduce transpiration.
• Other regions do not have rainy winters but rainy seasons.
• Vegetation in other regions shed their leaves.

Question 11.
Describe the steppes.
Answer:

• Steppes are temperate grasslands found in the mid latitudinal zones and interior parts of the continents.
• Usually grass here is short and nutritious.

Question 12.
What are Savannahs?
Answer:

• From equator to tropics on eitherside of equator, areas with moderate to low rainfall result in grasslands.
• These grasses are tall about 3 to 4 metres.
• Savannah grasslands are African tropical grasslands.

Question 13.
What is tundra type of vegetation?
Answer:

• In extreme cold polar regions natural vegetation consists of mosses, lichens and very small shrubs.
• These grow during very hot summer.
• This is called tundra type of vegetation.

Question 14.
How does the chemical “diclofenac” affect vultures?
(Or)
Why is the population of vultures decreasing?
Answer:

• The farmers use a particular chemical called Diclofenac to treat cattle.
• When the cattle die their flesh retain this chemical.
• When their flesh is consumed by vultures, diclofenac leads to kidney failure in them and they die.
• So the population of vultures is decreasing.

Question 15.
How are industries polluting our environment?
Answer:

• Modern industries use coal and petroleum.
• The burning of fossil fuels releases large quantities of carbon dioxide and other chemicals.
• Industries also cause the release of sulphuric, carbonic and nitric acids, which cause “acid rains.”
• Modern industries release enormous amounts of waste material which ^ air and water.

Question 16.
How does new agriculture affect our environment?
Answer:

• Modern agriculture uses a large amount of chemical fertilize
• These fertilizers and pesticides eventually remain in the soil, result in contamination of soil and water.
• As a result many micro organisms like earthworms are destroyed.
• This in turn affects the long term fertility of the soil.
• Due to modern agriculture, the levels of toxins in our food are increasing.
• This is very harmful to the health of the people.

Question 17.
Write about Kyoto protocol.
Answer:

• To protect the mother earth from global warming, a conference was held in the city of Kyoto in Japan.
• The main aim of this is to bring down the release of green house gases.

Question 18.
What are the impacts of Global warming?
Answer:
Concentration of green house gases raise the temperature of the earth. This is known as Global warming.

1. If CO₂ reaches twice, the global temperature could be 1.5°C and 4°C higher than that precondition.
2. The increased surface temperature would cause melting of continental and mountain glaciers and thus would cause flooding of coastal areas of low land countries.
3. A major portion of the lower deltaic region of Bangladesh would be submerged under sea water.
4. Green house effect could cause decrease in precipitation and soil moisture content in the world.
5. Due to decrease in rainfall our agriculture will be affected.
6. Due to decrease in moisture content in the atmosphere, diseases will spread.
7. Due to damage to the Ozone layer, skin problems will arise.
8. Decrease of snow cover in the northern hemisphere has been observed since 1973.

Question 19.
“Various forms of life are not only related to the three spheres around them but also to each other”- Interpret the statement.
Answer:

• All parts of life are part of a complex food chain that is one kind becomes the food for another kind.
• The primary food producers are plants which produce food with the help of sunlight.
• The food produced by plants are eaten by animals, usually called herbivores.
• Bacteria and fungi help in decomposition of dead trees, animals and breaking them down into organic compounds.
• The plants themselves draw the vital nutrients from these organic compounds.
• Thus many of the life forms are symbiotic that is they live by exchanging essential susbtances with each other.

Question 20.
“Any disturbance in the life cycle can create an ecological crises” – Explain the statement.
Answer:

• If a particular species feeds upon a particular kind of plant is exterminated, it would result in unchecked growth of that plant.
• Then that plant may intrude into the area of other plants and stop their growth.
• Many industries release their chemical wastes into the rivers and streams.
• These chemicals like mercury are consumed by micro organisms and in turn, become the food offish.
• When human beings consume these fishes they too absorb mercury which is detrimental to their health.
• Thus we can say any disturbance in the life cycle can create ecological crises.

Question 21.
“Since all living and non-living things on earth are in one way or other connected to each other, changes affecting one affects all others too” – Interpret the above statement.
Answer:

• Industries release chemical wastes into the rivers and streams.
• These chemicals like mercury are consumed by the micro organisms in water.
• These micro organisms become the food of the fishes.
• When human beings consume these fishes they too absorb quantities of mercury that are detrimental to human health.
• Thus all living and non-living things on earth are in one way or other connected to each other, changes affecting one affects all others too.

Question 22.
“Such intense human industrial activity has had profound impact on the air, water and the land around us” – Interpret the above statement.
Answer:
A) Impact of industries on atmosphere :

1. Modern industries by burning of fossil fuels release large qualities of carbon dioxide and other chemicals into the atmosphere.
2. These chemicals pollute the atmosphere and lead to global warming and acid rains.
3. Burning of fossil fuels and release of enormous amounts of waste materials by industries contaminate air, water and soil.
4. Industrial emissions of greenhouse gases cause an increase in the atmospheric temperature and thus it leads to greenhouse effect.

B) Impact of industries on water:

1. Many industries use chemicals and metals which they release into the streams and rivers.
2. These metals like mercury are consumed by the micro organism and in turn become the food of fishes. When human beings eat these fishes, it causes ill health for them also.
3. Many toxic synthetic chemicals that cannot be broken down at all by natural processes can cause serious harm to people, plants and animals.

C) Impact of industries on soil:

• Soil contaminated by heavy metals may pose a great threat to human health if the heavy metals enter the food chain.
• Soil contaminated by industrial chemicals can have negative effects on seed germination and dry matter production.

Thus intense human industrial activity has had profound impact on the air, water and the land around us.

Question 23.
Read the paragraph under the title “In addition to and soil” on page 57 and comment on it.
In addition to burning of fossil fuels, modern industries release enormous amounts of waste materials in the form of solid, liquid and gaseous waste contaminating air, water (both surface water like rivers and underground water of wells) and soil.
Answer:

1. Modern industries and transport system use adequate amount of energy.
2. The buring of fossil feuls releases large quantities of carbon dioxide and other chemicals like nitrogen oxides, sulfur dioxide, carbon monoxide, volatile organic compounds and heavy metals.
3. They also cause the release of sulfuric carbonic and nitric acids, which cause what are called “acid rains”.
4. Modern industries release enormous effluents of waste materials in the form of solid, liquid and toxic waste contaminating air, water and soil.

Question 24.
“Scientists believe that the earth’s climate is being altered due to changes in atmosphere known as the greenhouse effect. The greenhouse effect is particularly significant in the polar regions of the Arctic and Antarctic. On the Antarctic peninsula temperatures have been recorded as increasing two to three times more quickly than the rest of the Earth”- Form a question after reading the above passage.
Answer:
How does the greenhouse effect in the polar region affect the atmosphere and hydrosphere? How can it be a cause of concern for the low lying areas and islands?

Question 25.
“All small islands and low lying areas will be jeopardized. If global warming is allowed to progress, some of the northern Hawaiian atolls already been submerged by ocean water. Waikiki, Manhattan and New Orleans are good examples of major cities within the United States that may be at the risk of flooding” –
After reading the above passage, form a suitable question on the above discussed issue.
Answer:
Why is Hawaii in danger?

Question 26.
“Characterized as containing harmful levels of sulphur dioxide or nitrogen oxide, acid rain is damaging and potentially deadly to the earth’s fragile ecosystems; a pH – of 2.4 has been measured in rainfall in England” –
Read the above passage and form a question on the above discussed issue.
Answer:

1. How do acid rains affect the ecosystems?
2. What are the factors that result in acid rains?

Question 27.
If your acquaintant is now on a tree cutting spree, how would you stop him?
Answer:

• If my acquaintant is now on a tree cutting spree, I would advise him to stop it.
• I would let him know the ill effects of felling of trees.
• I would educate him of environmental crisis from this and global warming.
• I would make him to stop tree cutting.
• I would encourage him to plant more saplings than the number of trees he cut.

Question 28.
Locate the following on the world map.
1) China
2) Brazil
3) New Zealand
4) California
5) Chile
6) Mediterranean sea
Answer:

Question 29.
Can you name the great desert of India? Name some of the common animals of the desert which you have learnt earlier.
Answer:

• The name of the great Indian desert is the Thar Desert.
• It is a large, arid region situated in the north western part of the Indian subcontinent.
• It is mainly located in the state of Rajasthan.
• About 23 species of lizard and 25 species of snakes are found here.
• Some wild species such as the black buck, chinkara the Indian wild ass and camels.
• Other mammals found in this region are red ox and a wild cat, the caracal.

Question 30.
Establish the dependence of Biosphere on the remaining realms?
Answer:

• All the realms of the earth are interdependent on each other.
• For the occurrence of biosphere, there is every need of lithosphere.
• Without hydrosphere, life is not possible on the earth thus biosphere.
• Existence of atmosphere only makes our planet earth liveable otherwise it may be too hot and too cold to live in.
• Thus, biosphere depends on the realms of earth.

Question 31.
How do you preserve your Mother Earth?
Answer:

• We should see that the biodiversity is presereved.
• We should see some alternative energy sources such as Biogas and Solar energy etc.
• No industries should be allowed to flow chemicals or other waste material into the streams or rivers.
• Use of chemical fertilizers should be avoided.
• Use of plastic should be banned.
• Licence should be cancelled to all the factories which release green house gases into the air.
• Pollution caused by vehicles should be checked.

AP State Syllabus AP Board 9th Class Physical Science Solutions Chapter 8 Gravitation Textbook Questions and Answers.

AP State Syllabus 9th Class Physical Science Solutions 8th Lesson Gravitation

9th Class Physical Science 8th Lesson Gravitation Textbook Questions and Answers

Improve Your Learning

Question 1.
What path will the moon take when the gravitational interaction between the moon and earth disappears? (AS 2)
Answer:
The force of attraction between moon and earth is given by F = \(\frac{\mathrm{GMm}}{\mathrm{R}^{2}}\)
M = mass of the earth ; m = mass of the moon ; R = radius of the earth
Here the gravitational interaction between moon and earth disappears.
∴ G = 0 ⇒ F = 0

• Therefore the moon neither revolves around the earth nor fall into the earth.
• It takes a straight path away from the earth.

Question 2.
A Car moves with constant speed of 10 m/s in a circular path of radius 10 m. The mass of the car is 1000kg. Who or what is providing the required centripetal force for the car? How much is it? (AS 1)
Answer:
Speed of the car (v) = 10 m/s ; Radius of the path (r) = 10 m
Weight of the car (m) = 1000kg

The required centripetal force is provided by the friction between the tyres of the car and the road.

Question 3.
A small metal washer is placed on the top of a hemisphere of radius R. What minimum horizontal velocity should be imparted to the washer to detach it from the hemisphere at the initial point of motion? (AS 1, AS 7)

Answer:
Radius of hemisphere = R; Mass of hemisphere = M
Let the radius of washer = r and mass = m
Distance between hemisphere and washer = R + r
The centripetal force required to rotate the washer = \(\frac{\mathrm{mv}^{2}}{\mathrm{r}}\)
The gravitational force of washer due to hemisphere is = \(\frac{\mathrm{GMm}}{\mathrm{R}^{2}}\)
But the necessary centripetal force must be equal to the gravitational force

Question 4.
Explain why a long pole is more beneficial to the tight rope walker if the pole has slight bending. (AS 1, AS 7)
Answer:

• You must have noticed the circus artists doing rope walking.
• During this act, they carry a long bamboo pole in their hands.
• The reason for this is that the line joining the centre of gravity and centre of equilibrium must fall within the rope for achieving the stable equilibrium.
• Thus when an artist finds that he is falling towards left, he shifts bamboo pole towards right, so that his centre of gravity stay undisturbed.
• Thus he can balance himself on the rope.

Question 5.
Why is it easier to carry the same amount of water in two buckets, one in each hand rather than in a single bucket? (AS 7)
Answer:
It is because in the later case centre of gravity of our body shifts towards the bucket and there is a tendency that the line joining the centre of gravity and centre of equilibrium may fall outside our feet.

However in the former case the centre of gravity not only gets lowered, but also it is at such a point that line joining the C.G. and C.E. falls within our feet.
Hence one is a stable equilibrium.

Question 6.
What is the speed of an apple dropped from a tree after 1.5 second? What distance will it cover during this time? Take g = 10 m/s². (AS 1)
Answer:
An apple is dropped from a tree.
∴ Initial velocity u = 0 ; Time t = 1.5 s
a = g = 10 m/s2 ; Final velocity v = ?
v = u + at = 0 + 10 x 1.5 = 0 + 15 = 15 m/s
Distance covered (s) = ut + \(\frac{1}{2}\) at² = 0 × 1.5 + \(\frac{1}{2}\) × 10 × 1.5 × 1.5 = 0 + 5 × 2.25 = 11.25 m

Question 7.
A body is projected with a speed of 40 m/s vertically up from the ground. What is the maximum height reached by the body? What is the entrie time of motion? What is the velocity at 5 seconds after the projection? Take g = 10 m/s². (AS 1)
Answer:
Initial speed u = 40 m/s ; g = 10 m/s²
Maximum height reached (h) = \(\frac{\mathrm{u}^{2}}{2 \mathrm{~g}}=\frac{40 \times 40}{2 \times 10}\) = 80 m
Entire time of motion (T) = \(\frac{2 \mathrm{u}}{\mathrm{g}}=\frac{2 \times 40}{10}\) = 8 s
Entire time of motion is 8 seconds.
∴ It starts to fall down after 4 seconds.
At 5 seconds the body is in downward direction.
u = 0 m/s, a = g = 10 m/s², t = 5 – 4 = 1 sec.
v = u + at = 0 + 10 × 1 = 10 m/s
∴ The velocity at 5 seconds is 10 m/s downward.

Question 8.
A boy is throwing balls into the air one by one in such a way that when the first ball thrown reaches maximum height he starts to throw the second ball. He repeats this activity. To what height do the balls rise if he throws twice in a second? (AS 1, AS 7)
Answer:
The boy throws the second ball when the first ball reaches its maximum height. He throws twice in a second.
Time of ascent of first ball is 1/2 sec.
After 1/2 sec, the first ball starts to fall down and the second ball starts from ground.
Let the distance travelled = s meters.; Initial velocity = u m/s
Time of ascent (t₁) = 1/2 sec.

They reach a height of 15/4 meters.

Question 9.
A man is standing against a wall such that his right shoulder and right leg are in contact with the surface of the wall along his height. Can he raise his left leg at this position without moving his body away from the wall? Why? Explain. (AS 7)
Answer:

• When the right leg and right shoulder are in contact with the surface of the wall along the height of a man, his weight is towards the wall.
• The centre of gravity will be away from the foot. Just like in the case of carrying a bucket full of water with one hand.
• The line joins the centre of gravity and centre of equilibrium is not perpendicular to the horizontal.
• Hence he cannot lift his left leg without moving his body along the wall.

Question 10.
A ball is dropped from a height. If it takes 0.2 s to cross the last 6 m before hitting the ground, find the height from which it is dropped. Take g = 10 m/ s². (AS 1)
Answer:

For last 6 m, distance travelled
s = 6 m ; u = ? ; t = 0.2 sec ; a = g = 10 m/s²
s = ut + \(\frac{1}{2}\) at²
6 = u (0.2) + \(\frac{1}{2}\) × 10 × (0.2)²
6 = (0.2) u + (5 × 0.04)
6 – 0.2 = 0.2 u
5.8 = 0.2 u ⇒ u = \(\frac{5.8}{0.2}\) = 29
∴ u = 29 m/s
This u will be the final velocity while travelling the distance x.
∴ s = x, v = 29 m/s, a = g = 10 m/s², u = 0 m/s
v² – u² = 2as ⇒ 29² – 0 = 2 × 10 × x ⇒ x = \(\frac{841}{20}\) = 42.05 m
∴ Total distance = x + 6 = 42.05 + 6 = 48.05 m
∴ The ball is dropped from a height of 48.05 m.

Question 11.
A ball is dropped from a balloon going up at a speed of 5 m/s. If the balloon was at a height 60 m. At the time of dropping the ball, how long will the ball take to reach the ground? (AS 1, AS 7)
Answer:
At t = 0, the stone was going up with a velocity of 5 m/s. After that it moves as a freely falling body, with downward acceleration ‘g’.
If it reaches the ground at time t₁,

Question 12.
A ball is projected vertically up with a speed of 50 m/s. Find the maximum height, the time to reach the maximum height, and the speed at of the maximum height. (g = 10 m/ s²) (AS 1)
Answer:
Initial speed u = 50 m/s ; g = 10 m/s²

After reaching maximum height, the velocity becomes ‘zero’.

Question 13.
Two cars having masses m₁ and m₂ move in circles of radii r₁ and r₂ respectively. If they complete the circle in equal time. What is the ratio of their speeds and centripetal accelerations? (AS 1)
Answer:
Masses of cars : m₁ and m₂; Radius of circles : r₁ and r₂
Given that their time period is equal.

Question 14.
Two spherical balls of mass 10 kg each are placed with their centers 10 cm apart. Find the gravitational force of attraction between them. (AS 1)
Answer:
Masses of balls M₁ and M₂ = 10 kg each.; Distance d = 10 cm = 0.1 m
Gravitational force of attraction between them is

Question 15.
Find the free-fall acceleration of an object on the surface of the moon, if the radius of the moon and its mass are 1740 km and 7.4 × 10²² kg respectively. Compare this value with free fall acceleration of a body on the surface of the earth. (AS 1)
Answer:
Radius of the moon = 1740 km = 1740 × 10³ m
Mass of the moon = 7.4 × 10²² kg ; G = 6.67 × 10^-11 Nm² kg^-2
Free fall acceleration of a body on the surface of the moon

Question 16.
Can you think of two particles which do not exert gravitational force on each other? (AS 2)
Answer:
Two particles which do not exert gravitational force on each other will be mass less particles. But every particle has even a little mass. Hence we cannot find two particles which do not exert gravitational force on each other.

Question 17.
An apple falls from a tree. An insect in the apple finds that the earth is falling towards it with an acceleration g. Who exerts the force needed to accelerate the earth with this acceleration? (AS 7)
Answer:

• According to Newton’s third law, when an apple is freely falling, the force on the apple due to earth is equal to the force on the earth due to apple.
• The force is due to gravity, which causes acceleration in the body.
• As the insect is inside the freely falling apple, it feels that the earth is falling towards it with an acceleration ’g’.
• According to the insect, the acceleration is due to the force on the apple due to the earth.
• Actually the earth is not falling towards the apple.

Question 18.
A scooter weighing 150 kg together with its rider moving at 36 kin/hr is to take a turn of radius 30 in. What force on the scooter towards the center is needed to make the turn possible ? Who or what provides this? (AS 1)
Answer:
Weight of the scooter with rider = 150 kg
Speed = 36 km/hr = 36 × \(\frac{5}{18}\) = 10 m/sec.
Radius of the turning = 30 m
The force needed on the scooter towards the centre is centripetal force.

∴ A centripetal force of 500 N is required on the car.
This force is provided by the friction between the tyres of the car and road.

Question 19.
The bob of simple pendulum of length 1 m has mass 100 g and a speed of 1.4 m/s at the lowest point in its path. Find the tension in the string at this moment. (Take g = 9.8 m/sec²) (AS 1)
Answer:
Mass of the bob = 100 g = 0.1 kg ; Length of the string = 1 m
Speed of the bob v = 1.4 m/s ; Let the tension in the string be T.
The forces acting on the bob are

a) Weight of the bob mg, downwards
b) Tension in the string ‘T’ upward
Weight of bob = \(\frac{\mathrm{mv}^{2}}{\mathrm{l}}\)
Tension in the string T = g cos θ
∴ According to Newton’s third law

Question 20.
How can you find the centre of gravity of India map made with steel? Explain. (AS 3)
(OR)
Describe an activity to know the center of gravity of a India map.
Answer:

1. Take an India map made of steel.
2. Make holes at four different corners i.e., top, bottom, left, and right, and name them as A, B, C, and D as shown in figure.
3. Suspend the map through a hole A, by means of a string to a nail ‘P’ as shown in figure.
4. Suspend a plumb line from the nail P.
5. Draw the line AX along the plumb line.
6. Similarly suspend the map through other holes B, C and D and draw lines BY, CZ, DW along the plumb line.
7. These lines (more than two) intersect at a point.
8. This point (G) is the centre of gravity of the map.

Question 21.
Explain some situations where the center of gravity of man lies out side of the body. (AS 1)
Answer:
Centre of gravity of a human being is located interior to the second sacral vertebra.
Centre of gravity of man lies out side the body in the following situation :
a) While doing sit-ups.
b) While carrying a load like bucket full of water with one hand.
c) While walking on a narrow base like walking on a rope or pole or narrow wall, etc.
d) While walking with one leg.
e) As age increases its position changes.

Question 22.
Where does the centre of gravity of atmosphere of the earth lie? (AS 2)
Answer:
The earth’s atmosphere is about 10,000 km thick, but most of its bulk is contained in the first 11 km above the earth’s surface. Since the earth and its atmosphere are roughly spherical, the centre of the earth is also the centre of gravity of the earth’s atmosphere.

Question 23.
Where does the center of gravity lie, when a boy is doing sit-ups? Explain. (AS 7)
Answer:

• The centre of gravity of a boy when he start erect, falls in the foot.
• When he is doing sit-ups, the centre of gravity shifts from foot to his base.
• The weight vector also move from the base.
• Hence the boy stretches his hands or bends slightly towards the earth. While doing sit-ups, in order to make the weight vector pass through base, so that he acquire stability.

9th Class Physical Science 8th Lesson Gravitation InText Questions and Answers

9th Class Physical Science Textbook Page No. 126

Question 1.
What is that force?
Answer:
The force acting on these objects to make them move around another object, instead of moving in straight line in the gravitational force.

Question 2.
Is the motion of the earth around the sun uniform motion?
Answer:
The earth takes 365.25 days to complete one rotation around the sun. Hence it is uniform motion.

Question 3.
Is the motion of the moon around the earth uniform motion?
Answer:
Moon takes 27.3 days to complete one rotation around the earth, which does not change. Hence it is uniform motion.

9th Class Physical Science Textbook Page No. 127

Question 4.
Does the velocity of the body change in uniform circular motion? Why?
Answer:
The velocity of the body in uniform circular motion is constant.

If the velocity is not constant, the time period changes from time to time and it cannot be treated as uniform circular motion.

Question 5.
Does the body in uniform circular motion have an acceleration? What is the direction of acceleration?
Answer:
The body in uniform circular motion have an acceleration, which is directed towards the centre of the circle, known as centripetal acceleration.

9th Class Physical Science Textbook Page No. 129

Question 6.
Do you know what questions arose in his mind from this observation?
Answer:
When apple fell to the ground, Newton might have thought like this:
a) Why did the apple fall on the earth?
b) Why doesn’t the apple go up in the sky?
c) Whether all the objects fall to ground ?
d) What makes them to fall on the ground?

Question 7.
Why did the apple fall to the ground?
Answer:
The apple fell to the ground due to the gravitational attraction of the earth.

Question 8.
Why does the moon not fall to the ground?
Answer:
The gravitational force in the moon due to earth is equal to the gravitational force on the earth due to moon. Hence the moon does not fall to the ground.

Question 9.
What makes the moon to move in a circular orbit around the earth?
Answer:
The gravitational force between moon and earth act as centripetal force and makes the moon to revolve around the earth in uniform circular motion.

9th Class Physical Science Textbook Page No. 135

Question 10.
How do you feel during the free-fall of your body from the height?
Answer:

• I feel weightlessness during the free-fall of my body from the height.
• This is due to the gravitational force of earth on the body.

9th Class Physical Science Textbook Page No. 136

Question 11.
Try to balance ladder on your shoulder. When does it happen?
Answer:
When the centre of gravity of the ladder and the centre of gravity of our body lies in the same line then we can balance the ladder on our shoulders.

9th Class Physical Science Textbook Page No. 128

Question 12.
Can an object moVe along a curved path if no force acts on it?
Answer:

• If a body has to move in a curved path, its direction of velocity must change continuously.
• This is done by the centripetal force.
• Hence an object cannot move along a curved path if no force acts on it.

Question 13.
As a car speeds up when rounding a curve, does its centripetal acceleration increase? Use an equation to defend your answer.
Answer:
Centripetal acceleration \(a_{c}=\frac{v^{2}}{r}\)
As v increases, its centripetal acceleration also increases.

Question 14.
Calculate the tension in a string that whirls a 2 kg – toy in a horizontal circle of radius 2.5 iv when it moves at 3 m/s.
Answer:
Mass of the toy m = 2 kg ; Radius of the circle = 2.5 m ; Speed of the toy = 3 m/s
As the toy is moving in a horizontal circle, the necessary centripetal force is provided due to the tension in the string.

9th Class Physical Science Textbook Page No. 131

Question 15.
In figure, we see that the moon falls around earth rather than straight into it. If the magnitude of velocity were zero, how would it move?

Answer:
If the magnitude of velocity were zero, the moon would move towards earth due to acceleration due to gravity.

Question 16.
According to the equation for gravitational force, what happens to the force between two bodies if the mass of one of the bodies doubled?
Answer:

∴ The gravitational force will be doubled.

Question 17.
If there is an attractive force between all objects, why we do not feel ourselves gravitating toward massive buildings in our vicinity?
Answer:

• Earth is massive than the building.
• Hence the gravitational force between ourselves and earth is more than that of between ourselves and building.
• Hence we do not feel gravitating towards massive building in our vicinity.

Question 187.
Is the force of gravity stronger on a piece of iron than on a piece of wood if both have the same mass?
Answer:
Yes. The force of gravity is stronger on a piece of iron then on a piece of wood if both have the same mass.

Question 19.
An apple falls because of the gravitational attraction of the earth. What is the gravitational attraction of apple on the earth?
Answer:

• We know that acceleration due to gravity, g = \(\frac{\mathrm{GM}}{\mathrm{R}^{2}}\)
  Here M is the mass of the earth.
• In this mass of the object which is freely falling has no effect on ‘g’.
• Hence the gravitational attraction of apple on the earth is negligible.

9th Class Physical Science Textbook Page No. 133

Question 20.
Give an example for the motion of an object of zero speed and with non-zero acceleration?
Answer:
Protons and neutrons inside the nucleus.

Question 21.
Two stones are thrown into air with speeds 20 m/s, 40 m/s respectively. What accelerations are possessed by the objects?
Answer:
Stone -1 :
Initial velocity u = 20 m/s
After a time t, it reaches to ground then final velocity v = 0 m/s
Accelerahon = \(\frac{0-20}{t}=\frac{-20}{t} \mathrm{~m} / \mathrm{s}^{2}\)

Stone – 2 :
Initial velocity u = 40 m/s
Final velocity v = 0 m/s
Accelerahon = \(\frac{0-40}{t}=\frac{-40}{t} \mathrm{~m} / \mathrm{s}^{2}\)

9th Class Physical Science Textbook Page No. 135

Question 22.
When is your weight equal to mg?
Answer:
When we are on the surface of the earth, our weight is equal to ‘mg’ on earth.

Question 23.
Give example of when your weight is zero?
Answer:

1. When we are at the centre of the earth, our weight is zero.
2. When we are freely falling, we feel weightlessness.

9th Class Physical Science Textbook Page No. 138

Question 24.
Where does the centre of gravity of a sphere and triangular lamina lie?
Answer:
1) Centre of gravity of a sphere is a point where the whole mass of the sphere is assumed to be concentrated which is called centre.

2) Centre of gravity of a triangular lamina lies where the whole mass of the triangle is assumed to be concentrated which is centroid.

Question 25.
Can an object have more than one centre of gravity?
Answer:
Basing on the position or distribution of mass, an object can have more than one centre of gravity.

Question 26.
Why doesn’t the leaning tower of Pisa topple over?
Answer:

• The centre of gravity of the leaning tower of Pisa is very close to earth.
• Even though it is leaning, the line of action of total weight passes through the base. The base area of leaning tower of Pisa is very large. So it doesn’t topple over.

Question 27.
Why must you bend forward when carrying a heavy load on your back?
Answer:
If we bend forward, then the line of action of total weight passes through the body. So we are stable. Hence we must bend forward when carrying a heavy load on our back.

9th Class Physical Science 8th Lesson Gravitation Activities

Activity – 1 Uniform circular motion

Question 1.
Describe an activity to observe uniform circular motion.
Answer:
Uniform Circular Motion :
Uniform circular motion is a motion of the body with a constant speed in circular path.

Material required :
Electric motor, old C.D., small wooden block, battery, connecting chords, stop clock.

Procedure:

1. Take an electric motor and fix a disc to the shaft of the electric motor.
2. Place a small wooden block on the disc, as shown in figure.
3. Switch on the motor.
4. Find the time required to complete ten revolutions by the block.
5. Repeat the same two to three times.
6. We observe that the wooden block moves in a circular path with a constant speed.
7. So, this motion of wooden block is called uniform circular motion.

Activity – 2

Question 2.
Define centripetal acceleration and derive an expression for centripetal acceleration.
Answer:
Centripetal acceleration :
The acceleration which can change only the direction of velocity of a body is called centripetal acceleration.

Derivation :

1. Let a body is in uniform circular motion.
2. Draw velocity vectors at successive time intervals as shown in the figure.
3. Transfer tails of each velocity vector to coincide at a single point without changing their direction as shown in the figure.
4. In the above figure, the directed line joining two vectors represents change in velocity (Av).
5. Let us consider the change in velocity during the course of a complete revolution of a body i.e., the sum of the magnitudes of the changes in velocity during a complete revolution will be equal to the sum of the sides of the depicted polygon.
6. The smaller the sides of our polygon, the closer they cling to the circle of radius v, consequently the magnitude of change in velocity of the body during the course of revolution, will be equal to the circumference ’2πv’ of the circle.

9) As the vertex angle of isosceles triangle decreases, the angle between the change in velocity approaches to 90°.

10) Therefore, the acceleration of a body in uniform circular motion is directed perpendicular to its velocity.

Activity – 3 Free fall

Question 3.
Accelerahon is independent of masses.
Place a small paper on a book. Release the book with the paper from certain height from the ground.
a) What is your observation?
Answer:
The book and paper will fall on the ground at same time, if the paper is kept in the book. If the paper is kept on the book and released, then the paper will be separated from book and falls on the ground little bit later than the book.

b) Drop the book and paper separately, what happens?
Answer:
Book reaches the ground first, then the paper reaches.

Activity – 4

Question 4.
What is the direction of ‘g’?
Throw a stone vertically up. Measure the time required for it to come back to earth’s surface with stop clock.

a) What happens to its speed when it moves up and down?
Answer:

• When the stone moves up, its velocity decreases gradually and finally it becomes zero, because it is moving against the direction of gravitation.
• When its velocity becomes zero, it starts to fall down due to gravitational force of earth, and its velocity increases.

b) What is the direction of acceleration?
Answer:

• While the stone is moving up, the direction of acceleration is in upward direction, which is against to the direction of gravitational force.
• While the stone is falling down, the direction of acceleration is in downward direction, which is in the direction of gravitational force.

Activity – 5

Question 5.
Describe the method of measuring the weight of a free fail body.
Answer:

• Take a spring balance and suspend it to the ceiling and put some weight to it.
• Note the reading of the spring balance.
• Now drop the spring balance with load from certain height to fall freely.
• Carefully observe the change in the position of indicator on the spring balance scale while it is in free-fall.
• We observe that the indicator of spring balance shows zero while it is in free-fall.
• This is due to the weightlessness of a free-fall body.

Activity – 6

Question 6.
How do you demonstrate the changes during the free-fall of a body?
Answer:

• Take a transparent tray and make holes on opposite sides.
• Take two or three rubber bands and tie them tightly, close to each other between the holes.
• Now place a stone on the bands as shown in the figure.
• We observe that the bands bend due to the weight of the stone.
• Now drop the tray with stone.
• We observe that the bands do not bend. They straight.
• When in equilibrium on a firm surface, weight is evidenced by a support force. Then weight equals to mg.
• When the body falls freely then it experiences weightlessness.
• Even in this weightless condition, there is still a gravitational force acting on the body causing downward acceleration.

Activity – 7

Question 7.
Give one activity that showing center of gravity and balancing.
(OR)
How do you balance spoon and fork?
Answer:

• As shown in the figure arrange a fork, spoon and wooden match stick together.
• The combination will balance nicely on the edge of the glass.
  The weights of the spoon and fork will pass through the centre of gravity and the base (glass).

Activity – 8

Question 8.
Can you get up without bending?
Sit in a chair comfortably as shown in figure. Try to get up from the chair without bending your body or legs.

a) Are we able to do so? If not why?
Answer:

1. We cannot get up from the chair without bending our body or legs.
2. When we sit in a chair, we are in weightless condition.
3. We need a support force to get up from the chair.
4. This support force can be obtained by bending our body or legs.

Activity – 9

Question 9.
How do you balance a ladder on your shoulder?
Answer:

• Take a ladder.
• Find the mid stick by counting the sticks of the ladder.
• Put that mid stick on the shoulder and balance the ladder.
• That is the center of gravity of a ladder.

Activity – 10

Question 10.
How can you locate the centre of gravity of a uniform object?
Answer:

1. Take a meter scale.
2. Suspend it from various points.
3. We observe that it bends to one side.
4. Suspend it from the mid point.
5. We observe that the scale will be in horizontal position without bending to any side.
6. At this point, the scale behaves as if its entire weight is concentrated at this point.
7. The support given at this single point gives support to the entire scale.
8. This point is its centre of gravity.

Activity – 11

Question 11.
Identifying the centre of gravity of a ring.
The center of gravity of any freely suspended object lies directly beneath the point of suspension.

If a vertical line is drawn through the point of suspension, the center of gravity lies somewhere along that line. To determine exactiy where it lies along the line, we have only to suspend the object from the some other point and draw a second vertical line through that point of suspension. The center of gravity lies where the two lines intersect.

a) Where does the center of gravity of a ring lie?
Answer:
The centre of gravity of a ring lies at its geometric centre.

b) Does the center of gravity of a body exist outside the body?
Answer:
For the bodies which are in right angled triangle shape, the centre of gravity falls out side the body. Hence we can say the CG of a body may be outside or inside the body.

c) Does center of gravity of an object exist at a point where there is no mass of the object?
Answer:
The centre of gravity exist at a point where there is no mass of the object, for the objects like annual rings.

Activity – 12

Question 12.
Shift of the centre of gravity and its effects.
Try to touch your toes as shown in figure (a). Try this again when standing against a wall as shown in figure (b).

a) Are you able to touch your toes in second case as shown in figure? If not why?
Answer:

• We cannot touch our toes in the second case as shown in figure.
• When we stand erect with the support of wall, the centre of gravity shifts its place from second sacral vertebra to the place near to abdomen.

b) What difference do you notice in the center of gravity of your body in above two positions ?
Answer:

• In the first position, the centre of gravity is at a place near to the centre of back-bone.
• In the second position, the centre of gravity shifts from the place near to the centre of backbone to the place near to abdomen.

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 9 Credit in the Financial System.

AP State Syllabus 9th Class Social Studies Important Questions 9th Lesson Credit in the Financial System

9th Class Social 9th Lesson Credit in the Financial System 1 Mark Important Questions and Answers

Question 1.
Expand NABARD. (SA-III : 2015-16)
(OR)
Explain the term NABARD. (SA-II : 2017-18)
Answer:
National Bank for Agricultural and Rural Development.

9th Class Social 9th Lesson Credit in the Financial System 2 Marks Important Questions and Answers

Question 1.
500 and 1000 rupees notes were demonetized recently. How far is this helpful for Indian economy in your opinion? (SA-III : 2016-17)
Answer:
The decision of the government to scrape 500 and 1000 currency notes is affecting different class of society in a different way.
Poor class :
This class is affected adversely immediately. Because they use debit or credit card is very less.

Temporarily they face problem but they become normal within month.

Middle class :
They too have to stand on a big queue for short time because they still need the 100 rupee note, for making petty payments.

Upper class :
They too may face trouble for few days but their life would become normal very soon.

Long term benefits :

1. Developmental activities would pick up significantly as the tax revenue increases.
2. Corruption would reduce.
3. Government can reduce rates of taxes.
4. Illegal activities would reduce.
5. Dowry and other social practices like extravagant marriages would reduce due to white economy.

Question 2.
What do the banks do with the deposits which they collect from the public? (SA-III : 2016-17)
Answer:

• Banks keep only a small proportion of their deposits as cash with themselves.
• Banks in India these days hold about 15% of their deposits as cash.
• This is kept as provision to pay the depositors who might come to withdraw money from the bank on any given day.
• Banks use the major portion of the deposits to extend loans.
• There is a huge demand for loans for various economic activities.

Question 3.
Financial literacy is the process of equipping oneself with knowledge and information on financial matters. Taking interest in financial literacy helps one to goals and protect oneself from frauds and debts traps. It aims inculate savings habits improve the understanding of financial products leading to effective use of financial services and thus helps better money management further financial literacy facilitates easy access to financial services.
“Financial literacy is an important for consumer protection and financial stability”? Comment on it. (SA-II : 2016-17)
Answer:
Importance of Consumer protection and Financial literacy :

1. Ensure that financial markets are deep and serve the broad population.
2. Provide access to financial services for low income households and
3. Ensure long-term stability in the financial system.
4. Financial markets help to build consumer trust in financial institutions and ensure that financial institutions reach out to serve the needs of the population, including low-income households that often lack access to basic financial services.

Question 4.
Appreciate the role of self-help groups to fulfill the financial needs of poor women. (SA-II : 2016-17)
(OR)
Self help groups are the building blocks of organisation of the rurql and urban poor. Not only do women become financially self reliant, it is a platform to discuss and act on a variety of social issues such as health, nutrition, domestic violence etc.”
Do you agree with the above statement? Explain your answer. (SA-II : 2018-19)
Answer:

• The Self Help Groups played a very significant role in empowering rural women in India.
• Self Gelp Group fulfill the commercial requirements of poor women members by doing the small amount of daily savings and making contributions for few months till the time there is sufficient funds in the group to start lending.
• To empower the women they provide buffaloes on loan, sewing machines, and provide loan for small general stores etc.
• Not only these the SHG group protect the women from domestic violence and from social abuse etc.
• SHG’s work for rural and urban poor women.

9th Class Social 9th Lesson Credit in the Financial System 4 Marks Important Questions and Answers

Question 1.
“There are some major differences between the way formal and informal credit providers operate in India. While the formal credit providers follow certain rules and regulations framed by government, informal credit providers do not follow such rules. When the borrower could not repay as per the agreed terms, formal credit providers cannot use any illegal ways to get back the credit, whereas informal credit providers use many coercive and illegal ways which at times lead to borrowers committing suicides. Compared to the formal lenders, most of the informal lenders charge a much higher interest on loans. Banks and cooperative societies need to lend more. This would lead to higher incomes because many people could then borrow cheaply for a variety of different needs. They could grow crops, do business, set up small-scale industries etc. They could set up new industries or engage in business activity. Cheap and affordable credit for all is crucial for the country’s development.”
Q. “The rich households are availing cheap credit from formal lenders whereas the poor households have to pay a heavy price for borrowing from informal sources” – Comment in your own words. (SA-III : 2016-17)
Answer:
The main reason behind poor house holds depends on informal lenders/sources because banks do not wish to give loans to the poor, who have no collateral. Bank loans require proper documents and collateral. Banks prefer not to lend money to the poor farmers and landless labourers, because more often than not they don’t have the required documents to take loan.

But rich people have more properties, they should submits proper documents to banks for loan.

According to this, rich people are benefited with low rate of interest but poor people are suffered with high rate of interest.
So formal sector loans need to expand in rural areas for the development of poor.

Question 2.
What are the various services provided by the bank to the customers? (SA-II : 2018-19)
Answer:
Financial institutions means banks may differ in the type and number of services they provide to customers.

The services most often provided include a variety of checking accounts, savings accounts; certificates of deposits, and loans, including car loans and home mortgages.

Additional services may include safe deposit boxes and investment related services. Education loans to students also.

9th Class Social 9th Lesson Credit in the Financial System Important Questions and Answers

Question 1.
What are the two important functions of Banks?
Answer:
All commercial banks perform the following two functions.

1. Banks accept deposits from the customers and pay an interest on the deposits.
2. Banks lend loans to the customers and charge interest on the loans.

Question 2.
What is the primary source of income for banks?
Answer:
The difference between what is charged from borrowers and what is paid to the depositors is the primary source of income for banks.

Question 3.
What is meant by the term ’credit1 (loan)?
Answer:

• Credit refers to an agreement in which the lender supplies the borrower with money, goods or services in turn for the promise of future payment.
• Credit helps us to meet our needs or expenses.

Question 4.
What is meant by the term collateral?
Answer:
Collateral is an asset that the borrower owns (such as land, building, vehicles, livestock, deposits with bank) and uses this as a guarantee to a lender until the loan is repaid.

Question 5.
What are formal and informal sources of credit in India?
Answer:

• The various types of loans can be conveniently grouped as formal sector loans and informal sector loans.
• Among them, formel are loans from banks and cooperatives.
• The informal lenders include moneylenders, traders, employers, relatives and friends, etc.

Question 6.
What is meant by the word ’financial literacy’?
Answer:

• Financial literacy is the process of equipping oneself with knowledge and understanding on financial matters and to take right financial decisions leading to financial confidence.
• Simply, taking efforts to equip oneself with knowledge on financial matter.

Question 7.
Where do we get information regarding financial literacy?
Answer:

• Financial literacy material is available on the website of Reserve Bank of India.
• In addition, for the benefit of word illiterate persons in rural and urban and remote areas, State Level Bankers Committee (SLBC), AP has prepared an audio CD on the benefits of saving with banks.

Question 8.
What are “the terms of credit”?
Answer:
Interest rate, collateral and documentation requirement and the mode of repayment together comprise what is called the terms of credit.

Question 9.
Why do you think bank deposits are called ‘demand deposits’?
Answer:

• Banks accept the deposits and also pay an amount as interest on the deposits.
• People have the right to withdraw the money as and when they require.
• Since the deposits in the bank accounts can be withdrawn on demand, these deposits are called ‘demand deposits’.

Question 1o.
Why do you think the people in rural areas demand for credit?
Answer:

• In the rural areas, the main demand for credit is for crop production.
• Crop production involves considerable costs on seeds, fertilizers, pesticides, water, electricity, repair of equipment, etc.
• Farmers usually take crop loans at the beginning of the season and repay the loan after harvest.
• There is usually 3 to 4 months gap between farmers buying inputs and selling the crop.
• Repayment crucially depends on income from farming.

Question 11.
Read the passage and answer the following questions.

1) What has RBI initiated?
Answer:
The RBI has now initiated processes of improving the financial access to people in rural areas.

2) What would be the uses of RBI’s steps?
Answer:
They would encourage people in rural areas to open bank accounts, to save money ’ and also use loan facilities of the banks.

3) What initiations has the government taken recently?
Answer:
Recently, the government initiated providing unique identification number to every citizen of India.

4) What is the name of the card?
Answer:
Aadhaar card.

5) Is there any mandatory to put a minimum account?
Answer:
Now, there is no compulsion to keep a minimum amount. This is called ‘Basic Savings Bank Deposit Account’.

Question 12.
Understand the Pie diagram and fiSi the table.

Sources of credit for rural Households in India in 2003

Read the above table and Answer the following questions.
1) Note the change in the loans issued by all formal organizations for the last three decades.
Answer:
The loans issued by formal organizations has increased from 15.8% in 1961 to 52% in 2003. There is an increase of 36.2%.

2) What was the difference in the loans issued by all informal organizations for the last three decades?
Answer:
The loans issued by informal organizations have been reduced from 84.0 to 48%. There is a decrease of 36%

Question 13.
What are the reasons for farmers distress in Andhra Pradesh?
Answer:

• Most of the farmers take loans to meet the expenses of cultivation.
• When crops fail, they cannot repay the loans.
• Again they take a fresh loan from informal lenders.
• Finally fallen in debt-trap and this leads to distress among them.

Question 14.
What are the reasons for the poor notable to get bank loans, nowadays?
Answer:

• Bank loans require proper documents and collateral.
• Absence of collateral is one of the major reasons which prevent the poor from getting bank loans.
• They have a few assets to keep as collateral.
• They are going to easily accessible informal loans.

Question 15.
How is cheap and affordable credit for all, crucial for the country’s development nowadays?
Answer:

• Borrowing at higher rates of interest makes borrowers to have left with less income for themselves.
• In somecases it may be more than his income and leading to debt trap.
• For this reasons, banks and cooperatives need to lend more.*
• As these offer loans at lower rate of interest, borrowers use them for a variety of needs.
• Thus the availability of cheap and affordable credit for all is crucial for the country’s development nowadays.

Question 16.
Study the following pie-chart.

1) What does the above chart describe?
Answer:
It describes the distribution of credit among different households.

2) Describe the pie-chart.
Answer:

• Out of total credit, poor households take 40% of the credit.
• Out of total credit, rich households take 21% of the credit.
• Well-off households take 32% of credit and stood 2nd place in availing credit.
• Households with few assets take least percentage of loans, i.e. only 7%.

Question 17.
What is the measure taken by government and Non-governmental Organizations to organize rural poor?
Answer:

• In recent years government and NGOs have found new way for providing loans to the poor.
• The idea is to organize rural poor, particularly women into small Self Help Groups (SHGs) and pool their savings.
• SHGs with 15-20 members save Rs. 25 to Rs. 100, at least for 2 years.
• They can take small loans from group itself to meet their needs.
• Group charges small interest on borrowing members.
• After a year or two, they can get loan from bank without collateral.

Question 18.
What are the measures taken by RBI to help rural agriculture?
Answer:
1) The Reserve Bank of India sees that banks give loans not just to profit making business and traders but also to small cultivators, small scale industries, to small borrowers, etc.

2) In recent times, besides RBI, NABARD (National Bank for Agricultural and Rural Development) facilitates formal credit organisations in Rural India.

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 1 Our Earth.

AP State Syllabus 9th Class Social Studies Important Questions 1st Lesson Our Earth

9th Class Social 1st Lesson Our Earth 1 Mark Important Questions and Answers

Question 1.
Which continent is extended in four hemispheres In the given map. (SA-III : 2015 – 16)
Answer:

Africa continent.

Question 2.
What do you mean by anti meridian? (SA-III : 2016 – 17)
Answer:
The anti meridian is the meridian of longitude opposite the Prime-Meridian.

9th Class Social 1st Lesson Our Earth 2 Marks Important Questions and Answers

Question 1.
Draw the picture of the Globe and point out all the latitudes that are given special names on it. (SA-III : 2016 – 17)
Answer:

Question 2.
Why is it important to know the latitude and longitude of a place on map? How can it be useful? (SA-II : 2018 – 19)
Answer:
It is very important to know about latitudes and longitudes of a place by the following reasons.

• The particular location of a place on the earth can only be traced precisely with the help of latitude and longitude of that place.
• Latitude also help us in understanding the pattern of wind circulation on the global surface.
• Longitudes are useful to us to define the east-west position of a location on the planet.
• Longitudes are useful to us to know the time of the place.

Question 3.
Wegener hypothesised that the super continents of pangea broke up into two blocks –
1) Laurensia
2) Gondwana. It took millions of years for the continents to reach the present shapes and positions on the globe. (SA-I : 2018 – 19)
1) Laurensia : North America, Greenland, and all of the Eurasia north of Indian sub continent.
2) Gondwana : South America, Africa, Madagascar, India, Arabia, Malaysia, East Indies, Australia and Antartica.
Based on the above information given – answer the following questions.
a) Write any two land masses of present Asian continent which were formed from Gondwana?
b) From which block was the present Europe continent formed?
Answer:
a) India, Arabia, Malaysia, East Indies.
b) The present Europe continent was formed from Laurensia block.

Question 4.
If every state in India follows its local time then what problems will arise? (SA-I : 2019 – 20)
Answer:
If every state follows its local time, the following problems will arise :

• People travelling to different states would have to change their clocks too often.
• There would be confusion and chaos in the timings of railways, airlines, buses etc.
• The schedules of television shows, live shows and games, news etc. would be disrupted.

9th Class Social 1st Lesson Our Earth 4 Marks Important Questions and Answers

Question 1.
What is the difference between local time and standard time ? If every state follows its local time then what problems will rise in India? (SA-III : 2015 – 16)
Answer:
Difference between Local and Standard time:

Example:
If the IST is 12.00 noon, the local of Mumbai is 39 minutes – IST = 11.21 minutes a.m. Since Mumbai is on 72°82′ east longitudes, it is 9°45′ behind the 82°30′. Thus the local time of Mumbai is 9.45 x 4 = 38 minutes.

If every state follows its local time, a lot of serious problems would rise. Some of them are being discussed hereunder.

• At the time of national calamities and disasters, it is very difficult for the national government to make necessary emergency announcement.
• At the time of wars and national emergency it is very difficult for the national government to alert all the defensive forces stationed in all the state capitals and the naval forces of all the coastal states.
• It is very difficult for Televisions and Radios to follow a single schedule to broadcast their programmes.
• Railways faces a difficult problem in preparing a timetable for its trains that travel through many states.

Question 2.
Describe the internal structure of the earth. (SA-III : 2016 – 17) (SA-I : 2018 – 19)
Answer:
The earth is made up of three main layers.
A) Crust:

1. The outer part of the earth on which we live is called the crust.
2. While the earth was boiling in a molten form the lighter particles cooled at the top and formed the layer of crust.
3. The curst mostly consists of various kinds of rocks.
4. This layer goes up to a depth of 30 to 100 kms.

B) Mantle:

1. While the earth was boiling in a molten form the less heavier particles settled in the middle and formed the mantle.
2. The upper part of the mantle is a pliable layer over which the crust floats.
3. This layer consists mainly of chemicals called silicates.
4. It exists at the depths from 100 kms to 2900 kms.

C) Core:

1. While the earth was boiling in a molten form the heaviest substances formed core.
2. It is composed of dense and heavy substances like Iron and Nickel.
3. It exists at the depths from 2,900 kms to 6,376 kms.
4. It can be divided into two sub-layers.

a) Outer core :
This layer is composed of liquid metallic material like nickel and iron. It is 2,900 – 5,100 kms in thickness.

b) Inner core :
The solid inner core is made up of iron compounds and heavy substances like gold. It is 5,100 – 6,376 kms in thickness.

9th Class Social 1st Lesson Our Earth Important Questions and Answers

Question 1.
How can you say the man himself is responsible for environmental crises?
Answer:

• More than any other animal human beings have been trying to make the earth a better place to live in.
• Trying to change ourselves and our surroundings we have entered into conflict with other inhabitants of the earth.
• For long we’ve been exploiting the earth for its resources.
• The reckless exploitation of the earth resulted in environmental crises such as global warming and poisoning of our soils, water and air.
• Thus we can say man himself is responsible for environmental crises.

Question 2.
What were the initial ideas of people about the earth, the sun the moon and other astronomical bodies?
Answer:

• For thousands of years humans have been looking into the sky trying to understand objects that shine there.
• Initially, people thought that earth was firm and stationary and all others went round it.
• They also thought that the earth, the stars and the sun have been like this forever and will be like this forever without any change.

Question 3.
Write about the phases of evolution of facts, about the astronomical bodies their birth and growth.
Answer:

• Initially, people were of the view that the earth was firm and stationary and all the other bodies went round it.
• About five hundred years ago scientists concluded that the earth is not in the middle of everything.
• The earth actually moves round the sun and that the sun itself is also moving.
• The countless stars in the sky are actually so many suns.
• During the last hundred years or so people learnt the stars are born, they grow old and even die.
• Scientists even came to know that the stars are actually part of larger groups called galaxies.
• There are millions of galaxies in the universe.
• Now scientists are of the view that the universe itself started some 13.7 billion years ago with a Big Bang and it may end several billion years later.

Question 4.
How dkl the universe come into existence?
Answer:

1. The universe itself started some 13.7 billion years ago with a Big Bang.
2. From this Big Bang, several galaxies were formed.
3. Within these galaxies, stars were formed.
4. Planets were formed around stars and went around them.

However these astronomical changes take place over thousands and even millions of years.

Question 5.
Describe the process of evolution of the Earth.
(OR)
How did the earth come into existence and get its present form?
Answer:

• The earth began to form around four and a half billion years ago.
• It began as a ball of swirling dust and clouds and passed through a molten age.
• Gradually it grew in size.
• It was very hot and was in molten stage.
• The lighter particles cooled at the top and formed a layer of crust.
• Heavier particles formed the part of the molten core.
• As the earth’s interior cooled and contracted, the outer crust wrinkled, forming ridges and basins.
• The rain filled the basins and thus oceans formed.
• Slowly atmosphere developed and slowly life appeared on the earth.

Question 6.
How and when did the life appear on earth?
Answer:

• Different kinds of gases including water vapour formed the atmosphere on earth.
• Most of these gases were such that life as we know it today could not survive on it.
• Because it did not have oxygen necessary for life to survive.
• It took a long time for the air to develop.
• Then life appeared on oceans first.

It slowly evolved into diverse forms – plants, animals and human beings.

Question 7.
Are the shapes and positions of the continents fixed and permanent as they appear on the globe?
Answer:
The shapes and positions of the continents may seem fixed at the time scale of human experience. But on old earth continents have moved, collided, merged and then been torn apart again.

Mountains have risen and been razed to the ground, oceans have formed and dried up. Valleys have been carved and so during the course of earth’s eventful history. Alfred Wegener’s theory of Continental drift proves the same idea.

Thus the shapes and positions of the continents are not fixed and permanent.

Question 8.
Describe the theory of continental drift.
Answer:

• In 1912 Alfred Wegener propounded the theory of continental drift to describe the present arrangement of continents and ocean basins.
• He postulated a massive super continent Pangaea that existed 220 million years ago.
• Pangaea, the hypothetical continent, from which present continents originated by the drift from Mesozoic era to the present.
• Wegener hypothesized that the super continent of Pangaea broke up to from :
  a) Laurensia – consisting of present North America, Greenland and all of Eurasia north of Indian subcontinent and
  b) Gondwana land – consisting of present South America, Africa, Madagascar, Arabia, India, Malaysia, East Indies, Australia and Antarctica.
• These two blocks were separated by a long shallow inland sea called Tethys sea.
• It took millions of years for the continents to reach the present shapes and positions on the globe.
• Even today many of the continents are moving very slowly pushing each other.

Question 9.
What do you know about latitudes?
Answer:

• Latitudes are imaginary lines drawn around the earth.
• The word ‘latitude’ comes to us from the Latin word ‘iatitudo’ meaning width.
• Latitudes are also called parallels because they are parallel to each other.
• Latitudes are circles.
• Latitudes are expressed in degrees (°), minutes (‘) and seconds (“).
• Latitude values range from 0° t* 90° North (the North Pole) and 90° South (the South Pole).
• Thus there are 180° main latitudes (not counting the equator)
• Equator, the 0° latitude is the largest among all the latitudes.
• Latitudes are used together with the longitudes to locate a place on the earth.
• Latitudes are used to locate the climatic zones on the earth.

Question 10.
What do you know about longitudes?
Answer:

• Longitudes are imaginary lines connecting North and South’Poles.
• Longitudes are semi-circles.
• Longitudes are also called meridians because when the sun is overhead on a longitude at the time on that longitude it is noon (meridianus).
• There are 360 longitudes in total.
• The longitudes from 0° to 180° to the east are called eastern longitudes.
• The longitudes from 0° to 180° to the west are called western longitudes.
• 0° meridian is called the Prime meridian or Greenwich meridian.
• Longitudes are also expressed in degrees (°), minutes (‘) and seconds (“).

Question 11.
How are the time zones formed and why are they formed?
Answer:

• It takes 4 minutes for the sun’s position to move 1° of longitude.
• This means that the time is different for each degree of longitude.
• This can cause a lot of confusion.
• Therefore to end up this confusion the world is divided into 24 time zones.
• The width of each time zone is 15° of longitude.
• This means the difference between one time zone and the next is 1 hour.
• As you go from Greenwich meridian, you add time; as you go west of the Greenwich meridian you subtract time.

Question 12.
Why does every country have its own standard time?
Answer:

• The world is divided into 24 time zones.
• The width of each time zone is 15° of longitude.
• This means that the difference between one time zone and the next is one hour.
• Some countries would have more than one time zone with less than one hour division.
• This is considered too complicated to be useful.
• That is why some countries choose the time along one of the meridians that pass throught their territory and follow the time of that meridian for the whole country.
• This time is called standard time.

Question 13.
What is a Grid?
Answer:
A grid is a square or a rectangle that is formed between when two latitudes and longitudes out across each other. In other words, the network of latitudes and longitudes drawn on the globe is called a ‘grid’.

Question 14.
When it is 12 noon in Greenwich (0°), what is the local time at Mumbai (73° E)?
Answer:
Mumbai (73° E) : Local time at Mumbai is : 73 x 4 = 292 minutes, i.e. 4 hours 52 minutes. That means the local time at Mumbai is 4 hours 52 minutes after 12 noon i.e., 12.00 + 4.52 = 4.52 p.m.

Question 15.
When it is 12 noon in Greenwich (0°), what is the local time at Chicago (87°30′ W) ? Chicago (87°30‘ W) : Local time at Chicago is : 87°30‘ x 4 = 350 minutes, i.e. 6 hours 50 minutes. That means the local time at Chicago is 6 hours 50 minutes less than 12.00 noon at Greenwich.
i.e. 12.00-6.50 = 5.10 a.m.

Question 16.
When it is 12 noon in Greenwich (0°), what is the local time at Sydney (151° E)?
Answer:
Sydney (151° E): Local time at Sydney is 151° x4 = 604 minutes, i.e. 10 hours 4 minutes before Greenwich time.
That means the local time at Sydney is 12.00 + 10.04 = 10.04 p.m

Question 17.
a) What are called ‘parallels’?
b) What are called ‘meridians’?
Answer:
а) Latitudes are called ‘parallels’,
b) Longitudes are called ‘meridians’.

Question 18.
What is the standard meridian of India?
Answer:
82°30′ Eastern longitude is the standard meridian of India.

Question 19.
If you were to travel from India to Japan. How would be the change in time?
Answer:

1. Japan is located in East to India.
2. If we travel to East, then we gain time as per East Gain Add (EGA).
3. India is in 5Vi hours time zone and Japan in 9 hours time zone.
4. Both are in eastern hemisphere. Thus we gain nearly 3% hours time.

Question 20.
How do you think human greed led to exploitation of the earth?
Answer:

• Human life on earth dates back to one lakh years, whereas formation of the earth was four and a half billion years ago.
• Man has constantly trying to change our surrounding to make it a better place to live in.
• He looked on earth as a storehouse of resources and making use of it, at will.
• Thus his greed led to exploitation of the earth.

Question 21.
Why do you think, it took so long time to understand the interior of the earth?
Answer:

• It is difficult for man to know directly about the Earth’s interior.
• So far man could dig a 3 km interior of the earth.
• He could send pipes upto a depth of 6K km.
• But, the radius of the earth is 6,440 km.
• Apart from this, if we go deep the earth-temperature raises at a rate of 1°C for every 32 meters.
• An estimated temperature at the centre of the interior of the earth is 6000°C.
• Thus man was unable to get direct information.
• So he need to rely on indirect sources like seismic waves etc.
• Thus it took so long time to understand the interior of the earth.

Question 22.
Describe the earth’s interior.
Answer:

1. The earth has a radius of 6440 km.
2. The temperature increases at a rate of 1°C for every 32 mts. of depth.
3. The temperature at the centre of the earth would be 6000° C.
4. As such the rocks will be in molten stage.
5. Pressure also increases when one goes deeper into the earth.
6. The earth is made up of three layers. They are : 1) Crust, 2) Mantle, 3) Core.
7. These layers differ from one another in thickness and also in their physical and chemical compositions.

Question 23.
What is “continental drift theory”? Explain.
(OR)
What is the “theory of continental drift”?
Answer:

• Alfred Wagener postulated the theory of continental drift.
• It explains the present arrangement of continents and ocean basins.
• He postulated a massive super continent called “Pangaea” which existed 220 million years ago.
• Present continents originated, by the drift from this “Pangaea”.
• Wagener hypothesised that the supercontinent of Pangaea broke up into two blocks
  1) Laurensia,
  2) Gondwana land.
• The two blocks were separated by a long shallow inland ocean called “Tethys”.
• It took millions of years for the continents to reach the present shape and position.

Question 24.
Differenciate between latitudes and longitudes.
Answer:

Question 25.
How many blocks did the Pangaea brake up into? What are they?
Answer:
The super continent of Pangaea was broke up into two blocks.
1) Laurensia:
Present N.America, Greenland and all of Eurasia, north of Indian subcontinent formed from it.

2) Gondwana land :
Present S.America, Africa, Madagascar, India, Arabia, Malaysia, East Indies, Australia and Antarctica formed from it.

Question 26.
How do you find a place in an atlas?
Answer:

1. We can find the information about a place in an atlas with the help of latitudes and longitudes.
2. Places are listed alphabetically at the back of the atlas.
   Ex : To locate “Visakhapatnam”.

Question 27.
What are longitudes? How many are there? Name some important longitudes.
Answer:

1. The semicircles connecting pole to pole are called longitudes.
2. They are 360 in number.
3. Some important longitudes are :
   a) Prime Meridian – 0° longitude
   b) International Date Line – 180° longitude

Question 28.
“For long we have looked at the Earth as a store house of resources, which we can exploit and use at will. Gradually we are realizing the fallacy of this view point” – Interpret the above statement.
Answer:
For long we have looked at the earth as a store house of resources. With this view we recklessly exploited the earth and are responsible to the destruction of forests, rivers, hills, fellow animals and even fellow humans. This resulted in the environmental crises such as global warming and poisoning of our soils, water and air.

But gradually we understand that the earthly resources are not infinite but finite and the environmental system is a closed one. So we should not use the natural resources indiscriminately.

If a man has to survive, he must derive something from the nature. The exploitation of minimum resources from the natural environment to fulfil the basic needs of human society would cause disequilibrium of some sort in the ecological balance resulting into environmental degradation and pollution. We should always use the natural resources in such a way that they are always at available in a desired quantity and quality.

Question 29.
“Today more than any other time we need to build a new understanding of the Earth, how it works and what we do on it and what we do with each other” – Interpret the above statement.
Answer:
In the decades of 1970s there emerged a concern about the fear of depletion of natural resources because of irrational and rapacious utilization of natural resources. This serious concern arises from the fact-rapid rate of rapacious exploitation of natural resources and modern production processes and advanced technologies. Thus the exploitation of natural resources has threatened the stability and survival of natural ecosystems and existence of several plant and animal species.

Hence today more than any other time we need to build a new understanding of the earth, how it works and what we do on it and what we do with each other.

Question 30.
Read the following para and answer the questions.
Scientists have figured out that the stars are actually part of larger groups called galaxies and that there are millions of such galaxies in the universe. Now, they are of the view that the universe itself started some 13.7 billion years ago with a ‘Big Bang’ and that it may end several billion years later.
1) What is a galaxy?
Answer:
A larger group of stars is called a galaxy.

2) When was the ‘Big Bang’ happened?
Answer:
‘Big bang’ was happened some IB.7 billion years ago.

3) How many galaxies are contemplated by scientists?
Answer:
Scientists contemplated that there are millions of galaxies in the universe.

4) When would be the end of the universe?
Answer:
The end of the universe would be after several billions of years.

Question 31.
What factors determine the number of standard times of countries?
Answer:
Countries which have much east-west extension will have a number of standard times.
Ex: Russia.

Question 32.
Identify other names of “Earth”.
Answer:
Bhoomi, Prudhvi, Dharithri, Dharani, Pudami, etc.

Question 33.

Observe the table and answer the following questions.
1) Which is uppermost layer of the interior of the earth?
Answer:
Crust is the uppermost layer of the interior of the earth.

2) What is the thickness of the core?
Answer:
The thickness of the core is 3476 kms.

3) Which layer is supposed to have more gold?
Answer:
The inner core is supposed to have more gold.

4) What is the radius of the earth?
Answer:
The radius of the earth is 6376 km.

Question 34.
Observe the following table and answer the questions given below.

What is the latitudinal value of “Equator”?
Answer:
The latitudinal value of Equator is “0°”.

2) What is the name given to 90° N and 90° S latitudes?
Answer:
90° N is called North pole and 90° S is called South pole.

3) What are the values of Arctic and Antarctic circles ?
Answer:
The value of Arctic circle is 6634° N.
The value of Antarctic circle is 6634° S.

4) In which hemisphere is the Arctic circle situated ?
Answer:
Arctic circle is in Northern hemisphere.

5) Which latitude does not have any direction?
Answer:
The Equator does not possess any direction.

Question 35.
One among our ‘environment crises’ is the poisoning of air. in light of this, how would you assess the Government of Delhi, deciding to allow vehicles with odd and even number plates on alternate days?
Answer:

• Air pollution is one among the environmental crises we face.
• Government of Delhi decided to allow the odd number plate vehicles to ply on the Delhi roads the other day.
• This alternate day journey provision definitely reduces the traffic congestion.
• It also promises in reduction of pollution.
• Already petrol vehicles ply on Delhi roads was banned.
• Compressed Natural Gas is the need of the hour.
• However, care must be taken to disallow everyone to have a vehicle with odd number and another with even.

Question 36.
Observe the following pictures.

a) What do the above pictures represent?
Answer:
The above pictures represent the stages of continental drift.

b) Look at the above picture “2” and identify the following.
1) India,
2) Africa,
3) Tethys sea

c) Identify.
i) South America in picture “3”.
ii) Antarctica in picture “4”.
Answer:

Question 37.
How can you say the Earth’s orbit is nearly circular but not exactly circular or an elongated oval path?
Answer:

• The orbit is the path of the Earth around the sun.
• The difference between earth’s farthest point (about 152 million km from the sun and the closest point 147 million km) is very small.
• Thus we can say the earth’s orbit is nearly circular but not exactly circular or an elongated oval path.

Question 38.
Prepare a palmphet on environmental crises.
Environment Crises
Answer:
For longtime man looked on earth as a store house of resources and tried to exploit at will. His reckless exploitation of earth has meant distruction of forests, rivers, hills, fellow animals and even fellow human beings.

Global warming, which is caused by the increased presence of green house gases like carbon dioxide, methane etc. It is resulting in melting of ice and submerging of low lands and coasts.

Soil pollution is caused by excessive use of chemicals, fertilizers and pesticides in agriculture and industrial waste deposition. Soil erosion is caused by excessive falling of trees and lack of pastures.

Water pollution is caused by routing of industrial wastes into water, usage of chemicals and pesticides etc. Air pollution is caused by the emissions from vehicles, air conditions etc.

Question 39.
Create visual representation to understand the time as described in the earth’s origin to your birth.
Answer:

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 8 Service Activities in India.

AP State Syllabus 9th Class Social Studies Important Questions 8th Lesson Service Activities in India

9th Class Social 8th Lesson Service Activities in India 4 Marks Important Questions and Answers

Question 1.
‘Service sector is beyond the other two sectors in providing employment’.
“Ramesh is a self employee who established an internet centre after completion of B.Tech. He also provided employment for two more persons”.
‘Service sector plays key role in providing employment’ comment on it. (SA-III : 2015-16)
Answer:
Yes. Services sector plays key role in providing employment by the following ways.

1. There has been tremendous change in the communication technology which has opened a wide range of jobs for educated people.
2. Business Process Outsourcing (BPO) has brought in new kinds of employment opportunities.
3. They provide services to people located across the globe using telecommunication links.
4. The entertainment industry creates jobs to work in various print media firms, cable television channels.
5. We see number of internet cafes and telephone booths in most of the cities and towns.
6. The advertising industry has also brought new job opportunities.
7. Many new jobs are available in Banking and insurance sectors.

Hence service sector can reduce educated unemployment in our country.

Question 2.
The table below shows the number of workers (in lakhs) employed in different service activities in large government enterprises in 1991 and 2010. Study the table and answer the question given below. (SA-II : 2018-19)

a) Which service activity provided least employment?
b) Write any two jobs related to community, social and personal services.
c) What kind of service activity jobs have shown maximum decrease in 2010?
d) What kind of service activity jobs has government-generated most in 2010?
Answer:
a) Wholesale and retail trade

b)

1. Washing and drycleaning work
2. Beauty treatment
3. Tailoring work
4. Barbour work (Hair cutting)
5. Who runs the photo studio.

c) Transport, storage and communications.

d) Finance, insurance, real estate etc.

9th Class Social 8th Lesson Service Activities in India Important Questions and Answers

Question 1.
How is service sector different from other sectors?
Answer:

• Other sectors, agriculture and industry produce goods that are tangible.
• But service activities do not produce any tangible good.
• But service activities fulfill the needs cater the requirements of people or organisations.
• They are also essential for agriculture and industrial activities.
• Non-production of commodity or good is the essential nature of service sector.

Question 2.
Is service sector, the heaven of dream jobs?
Answer:

• No, I don’t think so.
• Dream jobs in service sector are at a rate of one in tens of thousands of jobs.
• Remaining, especially uneducated and less educated do jobs with meagre wages.
• Those who have dreams are also under constant pressure and job stress.

Question 3.
Read the following case history and answer the following questions.

1) What was the position of the family before getting a job?
Answer:
Earlier there were a lot of financial problems in the family – his brothers and sisters were not able to study properly due to this.

2) What is his family’s financial position now?
Answer:
Working in software has added comfort to his life, and his brothers and sisters are able to study properly now.

3) Is the individual happy with his lifestyle?
Answer:

• He is earning good salary and that added comfort to his life.
• But at the same time the job is very stressful and his life is mechanical.
• He is missing his village, neighbours and relatives.

Question 4.
What is the work going on here in the given picture? Describe it in five sentences.
Answer:

1. It is a call centre job.
2. A call centre is an office where people work answering or making telephone calls for a particular company or customer regarding certain information.
3. The information may be regarding customer’s bank deposits or about their hospital records.
4. There will be three shifts and employees may have to work during nights too.
5. Salaries are high and at the same time lots and lots of stress in the job can be experienced.

Question 5.
What services, in your opinion, are desired today?
Answer:

• India faces an acute shortage of skilled human resources in the health sector. So health services are desired today.
• More infrastructure service is the need of the hour. So roads, hospitals and educational institutions are to be set up.
• We need good storage facilities as well as credit facilities.
• New economic policies in India shall emphasize the expansion of service activities.

Question 6.
Why do you think more people are engaged in low income service activities today?
Answer:

• With lack of job opportunities many people today are employed in low income services.
• Closure of factories forced workers to work as small vendors, rickshaw pullers and other low income service professions.
• People from rural areas are not getting opportunities in urban areas.
• They shift to many unskilled low earning employment opportunities in services.

Question 7.
Many unskilled have low earning employment opportunities in service sector. State your opinion.
Answer:

• People from rural areas come to work in the city but there are not enough employment opportunities in urban areas.
• Hence most of the unskilled are earning their livelihood as small vendors, rickshaw pullers, etc.
• They are unable to make both ends meet.

Question 8.
New job opportunities are depressing the employees. Comment on it (especially in IT).
Answer:

• New jobs are providing good salaries but the employees are also expected to work very long hours.
• The life is very stressful and mechanical.
• There is no social life.
• These jobs definitely depress the employees.

Question 9.
What measures are taken by companies to reduce cost and avoid paying benefits to workers?
Answer:

• In order to reduce cost and avoid paying health, pension and provident fund benefits to workers, industries ‘outsource’ security services to security agencies.
• Many companies outsource their work for research and development, accounting, legal services, customer service, public relations etc.

Question 10.
Many people work in service jobs. Few people do voluntary service. What measures would you take to distinct them?
Answer:

• Voluntary service means that is done free of cost or out of love and devotion.
• It doesn’t contribute to their livelihood.
• They have other occupation but do this as charity.
• On the otherhand, the people who work in service sector earn livelihood through it.
• They do specialised services required for people or organisations.

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 7 Industries in India.

AP State Syllabus 9th Class Social Studies Important Questions 7th Lesson Industries in India

9th Class Social 7th Lesson Industries in India 1 Mark Important Questions and Answers

Question 1.
Study the map given below and answer the following question. (SA-II : 2018-19)

Q : Where in Karnataka are the steel plants located?
Answer:
Vijayanagar and Bhadravathi are the two places has steel plants in Karnataka.

9th Class Social 7th Lesson Industries in India 2 Marks Important Questions and Answers

Question 1.
Draw a bargraph based on the given information. (SA-III : 2015-16)

Answer:

Question 2.
The pie charts below show the percentage of people employed in Agriculture. Industry and service sectors. Read the pie charts carefully to answer the question.

How did the pattern of employment change between 1972-73 and 2009-2010? (SA-II : 2018-19)
Answer:

1. The employment generation in agricultural sector has been decreased from 74% in 1972-73 to 53% in 2009-10.
2. The employment generation in industrial sector has been increased from 11% in 1972-73 to 22% in 2009-10.
3. The employment generation in service sector has shown an increase of 10%.

9th Class Social 7th Lesson Industries in India 4 Marks Important Questions and Answers

Question 1.
Observe the ‘Pie Chart’ and answer the following questions. (SA-III : 2015-16)

Answer the following Questions.
1. What does the above given graph denotes?
2. What is the percentage of change in employment by industry when compare between 1972-73 and 2009-10?
3. Which sector generated highest employment in 2009-10?
4. Write any two occupations regarding service sector?
Answer:

1. The above graph explains % of employment in different sectors.
2. From 1972-73 to 20019-10 the change in employment in Industrial sector is from 11% to 22%.
3. Agricultural sector.
4. Doctor, lawyer, teacher, banking, commerce, communications etc. are the occupations in the sector.

Question 2.
“Industries are necessary for the development of a nation. It is also fact that industrial activities are increasing environmental problems” – Write your opinions on this matter in detail. (SA-III : 2016-17)
Answer:
Industries are necesary for the development of a nation by the following ways.

1. When goods made in factories and exported to other countries, we get revenue.
2. A few decades before, three-fourths of income from goods exported from manufacturing industries alone.
3. Even today, nearly two-third of goods exports is contributed by industries and particularly small industries.
4. Factory goods exported range from gems, jewellery, chemicals, cars, machinery, cashewnuts, etc.
5. The money or foreign exchange earned in this process enable us to import from other countries a large number of goods that we want from other countries.

At the same time industrial activities are increasing environmental pollution by the following ways.

1. The production process in industries involves the use of electricity and application of different chemicals.
2. In the course of production, these industries release a lot of other materials. They are causing pollution in the industrial locations.
3. The industrialization led to the indiscriminate exploitation of minerals, forests, soils, air, etc.
4. It leads to deforestation and damages the natural habitat of animals.
5. Underground water is being contaminated due to the release of wastes by the industries.
6. Some animals are endangered and some creatures have become extinct.
7. The depletion of ozone layer, pollution of water, air, soil has increased ecological problems.

Question 3.
Mixing of some poisonous substances in air, water and soil causes to ‘ecological crisis’ – give your suggestions to prevent this problems as a student. (SA-II : 2017-18)
Answer:
Pollution prevention is a major global concern because of the harmful effects of pollution on a person’s health and on the environment.
Suggestions:

1. Stop smoking or at least follow the “No smoking” sign.
2. Never use open fires to dispose of wastes.
3. Instead of using your cars, choose to walk or ride a bicycle whenever possible.
4. Adopt the BRs. of solid waste management, reduce, reuse and recycle.
5. Use eco-friendly or biodegradable materials instead of plastic.
6. Do not cause loud noises and unwanted sounds to avoid noise pollution.
7. Industries should use fuel with lower sulphur content.
8. Industries should strictly follow applicable government regulations on pollution control.

Conclusion :
Breathing is life. We know that we will survive without food for several weeks and without water for few days, but without oxygen, we will die in a matter of minutes.

The oxygen, the air we breathe sustains us. So, let us make today and every day a good day for everyone.

Question 4.

Read the above pie chart and answer the following questions. (SA-II : 2017-18)
1. What does the pie chart tell us?
2. Which sector provide the highest percentage of employment?
3. In which sector employment increased twice?
4. By 2009-10 which sector was the second piace in empioyment?
Answer:

1. Pie chart tells us the percentage of employment in different sectors from 1972-73 to 2009-10 years.
2. Agriculture sector provide highest percentage of employment.
3. In Industrial sector employment increased twice.
4. By 2009-10, the services sector is in second place in employment.

Question 5.
When people buy groceries, they may have their groceries packed in plastic bags, paper bags, or cloth bags they bring with them.
Which type of grocery bag is the best to help protect the environment?
a) Plastic
b) Paper
c) Cloth
Explain in what way your choice of bag can help protect the environment.
Answer:

• My choice is paper bag and cloth bag. Both are best to use.
• We should not use plastic bags as they are threat to environment.
• Plastic bags are not eco – friendly: They won’t decompose quickly, if you burn them also it will take time to mix with soil.
• Recently in Vijayawada, some areas of the city drowned in rainwater because all the sewage drains were filled with bunches of plastic bags.
• But paper and cloth bags will decompose in very short period and completely eco friendly.
• Paper bags made by wood pulp it may cause deforestation.
• Cloth bags made of cotton, quickly it decomposes.

9th Class Social 7th Lesson Industries in India Important Questions and Answers

Question 1.
Why are the infrastructure facilities important in establishing industries?
Answer:

• Building of roads, good transport facilities, power supply and telephone connections, etc. can be termed as infrastructural facilities.
• Factories need raw materials. These raw materials are to be transported to the factory sites. Hence good road ways and other facilities are needed.
• Factories need power to run machines. Hence all infrastructure facilities are needed.

Question 2.
Why are industries important?
Answer:
In industrial sector, the raw materials are worked upon by people and changed using tools and machines to produce a good that can be useful.
The importance of industries :
i) Industries provide a wide range of products :
There are plenty of goods made in factories. Ranging from paper and other stationery, fridges to cars, batteries, bulbs and other electrical appliances.

ii) Industries are expected to employ a large section of people looking for jobs :

1. Generating employment to work in factories is generally considered as one of the indicators of development and improvement of well being of people.
2. Employment in industries has increased from 11% in 1972-73 to 22% in 2009-10.

iii) Industries are important source of export incomes:

1. We earn a lot of foreign exchange by selling industrial goods to foreign countries.
2. Even today, nearly two-thirds of goods exported is contributed by industries.

Question 3.
What were the restrictions introduced by the government during the early years of industrialization?
Answer:

• Many industrial activities were allowed only for small producers. For example, production of cloth of specific quality was restricted to handlooms.
• Government made laws so that the large factory owners get prior permission or license to set up factories. This was done so that there would be better planning.
• The government regulated the quantity of goods produced by factories.
• The price at which they can be sold was also fixed.

All these restrictions were introduced keeping in view the welfare of the people.

Question 4.
Industrial policies of the early years became hindrance to the growth of industry. Explain.
Answer:

• Entrepreneurs were required to follow so many procedures and had to wait for many years to get the approval from the government offices.
• Licenses were not given to the most efficient producers.
• The selection was biased in favour of people with political connections and the economically powerful.
• All this discouraged new entrepreneurs who would work with latest technology available.
• Further control on prices led to shortage of goods. E.g.: Scooters.
• Such shortages were common for important basic goods like coal and cement, which in turn caused a lot of delay in production of other goods.
• Another problem was lack of quality of some of goods.
• There were restrictions on the import and export of industrial goods including machinery and raw materials.
• Prices were laid down by the government and the producers had to sell only at that price.
  So the above restrictions acted as hindrance to the growth of industry.

Question 5.
Write about the impact of industrial policies.
Answer:
The following are the impacts of industrial policies of government.
i) Rise in the number of industrial units:
Today nearly 2 lakh large factories and 3 crore small factories are operating in India.

ii) Employment has increased but less than expected:
Both small and large scale employ nearly about one-fifth of India’s 460 million workers.

iii) Low salaries and less working conditions:
A large section of workers are employed in small units which generally pay very low salary and devoid of workers safety conditions and health benefits.

iv) Production of factory-based goods has increased:
Establishment of basic industries resulted in increased production of factory based goods.

1. The production of coal and lignite has increased from 32 million tons in 1950-51 to 571 million tons in 2010-11.
2. The production of steel has increased from 10 million tones in 1980-81 to 70 million tons in 2010-11.
3. There was also a significant increase in the production of crude oil and cement etc.

v) Increase in environmental problems, land conflicts and pollution:
These industries release a lot of waste materials into the atmosphere and into the tanks and wells causing lots of air pollution and damaging water resources. The air pollution is causing skin diseases and respiratory diseases.

Question 6.
At the time of independence what were the objectives that were desired to be achieved through industrialization?
Answer:

1. After 1947, India began many initiatives to promote industrial activities in the country.
2. Major objectives were – to become self-sufficient in meeting our needs and to make the country an industrially developed nation.

Question 7.
Where should the sugar and jaggery mills be ideally located?
Answer:
The sugar and jaggery milis should be ideally located near the crop grown areas.

Question 8.
Where would it be economically viable to set up the cement manufacturing units?
Answer:
Cement manufacturing units can be established near the areas where the raw materials are available in bulk.

Raw materials :
Limestone, silica, alumina, gypsum, coal and electric power and transportation facilities.

Question 9.
Name the important centres of cotton textiles in Gujarat.
Answer:
Ahmedabad, Vadodara, Surat, Rajkot and Porbandar.

Question 10.
Where are the silk textile industries located in Jammu and Kashmir?
Answer:
In Baramula, Srinagar and Anantanag.

Question 11.
What are the basic requirements of industrialization?
Answser:

• Industrialization means to develop a large number of different factories.
• For industrialization, we have certain basic requirements.
• They are machines, electricity, minerals and ores and transport facilities.

Question 12.
What factors influence the selection of an industrial location?
Answer:

• Industrial locations are complex in nature.
• These are influenced by raw material labour, capital, power, and market, etc.
• It is rarely possible to find all these factors available at one place.
• So industries are located where these factors even can be arranged at lower cost.

Question 13.
What is an agrobased industry?
Answer:
The industries which are based on agricultural products are called ‘agrobased industries’.

Question 14.
Why do you think cotton textile industry is concentrated in Maharashtra and Gujarat?
Answer:

• Many factors support the concentration of cotton textile industry in Maharashtra and Gujarat.
• Availability of raw cotton, market, transport including accessible port facilities, moist climate etc. are some factors.
• Apart from these, availability of abundunt electricity at cheap prices and availability of skilled and unskilled labour in abundance add to those factors.
• These places also have investment supports from Banks and international market demands.
• Above factors help the flourishing of cotton textile industry in Maharashtra and Gujarat.

Question 15.
Read the following passage and answer the questions given below.

1) What is the industry mentioned in the above passage?
Answer:
Jute industry.

2) What are the challenges faced by the industry?
Answer:
Challenges faced by the industry include stiff competition in the international market from synthetic substitutes and from other competitors like Bangladesh, Brazil, Philippines, Egypt and Thailand.

3) When was National Jute Policy formulated?
Answer:
In 2005.

4) Name the main markets mentioned in the passage.
Answer:
USA, Canada, Russia, United Arab Republic, UK and Australia.

5) To stimulate demand, the products need to be
Answer:
diversified.

Question 16.
Discuss what is meant by the word “basic”? What are the basic necessities for industries?
Answer:

• “Basic” means the things that are basically necessary.
• The basic necessities for setting up any industries are machines, electricity, minerals and ores and infrastructural facilities like transport, telephone, etc.

Question 17.
Today West Bengal is the dominant state in Jute Industry. How is it able to become like that?
Answer:

• Most Jute mills in India are in West Bengal, mainly along the banks of the Hugli river 98 km long and 3 km wide.
• Hugli basin is in proximity of Jute producing areas, inexpensive water transport, supported by a good network of railways, roadways and waterways to facilitate movement of raw materials to mills.
• Abundant water for processing of raw jute, cheap labour from West Bengal, Bihar, Odisha and Uttar Pradesh.
• Kolkata provides banking, insurance and port facilities for export of jute goods.
• It provides direct or indirect employment to more than 40 lakh people.

Question 18.
Name the problems that are faced in the Iron and Steel industry?
Answer:

• It needs huge capital investment, which is difficult for developing country India.
• Indian technology is now far behind the advanced countries.
• Low per capita productivity and low potential utilization are to be addressed.
• Even at a low per capita consumption, demand for our production is not sufficient.
• Now we are importing iron and steel by spending precious foreign exchange.
• All the above problems needed to be solved.

Question 19.
Locate the following industrial cities on the outline map of India. City

Question 20.
Observe the following map and answer the questions given below.

1) Where do you find both cotton and woollen textiles?
Answer:
In Ahmedabad and Kanpur.

2) What is the South India state famous for silk textiles?
Answer:
Karnataka.

3) Name the important centres of cotton textiles in Gujarat.
Answer:
Ahmedabad, Vadodara, Surat, Rajkot and Porbandar.

4) Which type of textile industries are in major position in Maharashtra?
Answer:
Cotton textile industries.

5) Where are the silk textile industries located in Jammu and Kashmir?
AIn Baramula, Srinagar and Anantanag.

Question 21.
Observe the following map.

Now answer the questions given below.
1) What are the minerals mentioned in the map?
Answer:
Iron ore, manganese, bauxite and mica.

2) In which states do you find iron ore mines?
Answrr:
Maharashtra, Karnataka, Odisha and Chattisgarh.

3) What are the iron ore ex-porting ports mentioned in the map?
Answer:Visakhapatnam, Managalore, Marmagao and Paradwip.

4) Where can we find mica in Andhra Pradesh?
Answer:
In Nellore.

5) What is the mineral found in Rajasthan?
A. Mica.

Question 22.
Observe the following map.

Now answer the questions given below.
1) Which state is Raniganj coal mine located in?
Answer:
West Bengal

2) Where is the coal field located in Tamilnadu?
Answer:
Neyveli

3) Name the important coal mine of Telangana.
Answer:
Singareni

4) What is the coa! field that belongs to Chattisgarh?
Answer:
Korba

Question 23.
What steps are to be taken to reduce the problems of pollution?
Answer:

• We should stop effluent flow into water bodies.
• Provide safety drinking wafer to the affected villages.
• Continuous vigilance in discharge of effluents.
• Medical care to pollution victims.
• Cancellation of licence to pollution causing industries.

Question 24.
What measures would you suggest to overcome the problems of Textile Industry?
Answer:

• Care should be taken to increase the supply of raw material.
• Obsolute machinery which resulting in low productivity and inferior quality should be replaced.
• Government should provide adequate power to textile industry.
• Care should be taken that textile industry shall not lost in the stiff competition with power loom and synthetic fiber products.
• Many textile mills are sick, government should help them run properly.

Question 25.
What suggestions would you make to improve jute industry?
Answer:

• The best way to solve the problems of jute industry is to increase production.
• There is an urgent need to replace the old machinery.
• Jute mills are needed to be modernized.
• New Jute products are to be developed.
• The product range of jute is to be diversified.

AP State Syllabus AP Board 9th Class Social Studies Important Questions Chapter 4 Atmosphere.

AP State Syllabus 9th Class Social Studies Important Questions 4th Lesson Atmosphere

9th Class Social 3rd Lesson Hydrosphere 1 Mark Important Questions and Answers

Question 1.
Why does our skin dry up more during the winter? (SA-II : 2018-19)
Answer:
If the humidity is low in our atmosphere, our skin becomes dry during winter. This also leads to chapped lips.

Question 2.
Define relative humidity. (SA-I : 2019-20)
Answer:
Relative humidity: Relative humidity is the ratio between two things.

1. The maximum water vapour that the air can hold at a given temperature and pressure and
2. The actual amount of water vapour it holds at any given time.

9th Class Social 4th Lesson Atmosphere 4 Marks Important Questions and Answers

Question 1.
How many types of rainfall classified based on the origin of rainfall? What are they? Explain one of them? (SA-II : 2016-17)
Answer:
On the basis of origin, rainfall may be classified into three main types.

1. Convectional Rainfall
2. Orographic Rainfall
3. Cyclonic Rainfall.

Convectional Rainfall :
This type of rainfall occurs when moist air over the heated ground becomes warmer than the surrounding air and is forced to rise, expand, cool and yield some of its moisture.

It is common in low latitudes and on summer days in interior part of the continents, and usually come in the form of short heavy showers just after the hottest part of the day, some times accompanied by thunder and lightning.

Question 2.
Observe the information given below and write four sentences on ‘Pressure Beits and Planetary Winds’. (SA-III : 2016-17)

Answer:
According to the given picture :

• The Equatorial Low Pressure Belts : This low pressure belt extends from 0 to 5° North and South of the Equator.
• Sub – Tropical Pressure Beits : At about 30° North and South of the equator lies the area where the ascending equatorial air currents descends.
• Sub-polar Low Pressure belts : These belts are located between 60° and 70° in both the hemispheres and are known as sub-polar low pressure belts.
• Polar High Pressure belts ; At the North and South between 70° and 90° temperatures are always extremely low. These areas of polar high pressure are known as polar highs.

Planetary winds : Planetary winds are distributed all over the globe and blow in the same direction throughout the year. These winds originate due to the presence of permanent high pressure and low pressure belts on the surface of the earth. The main types of planetary winds are the trade winds, the westerlies and the polar winds.

Question 3.
Study the table and answer the questions given below. (SA-I : 2018-19)

1. Why do jet aircrafts fly in the stratosphere?
2. Which is the top most layer?
3. Which layer contains ions?
4. In which layer does precipitation and cyclones occur?
Answer:

1. Stratosphere layer is almost free from clouds and associated weather phenomenon, making conditions most ideal for flying jet aircrafts.
2. Exosphere. It is above 400 kms. It is uppermost layer of the atmosphere.
3. Thermosphere contains electrically charged particles known as ions.
4. Troposphere.

Question 4.
What are the effects of climate change on the contemporary World? (SA-I : 2018-19)
Answer:
The affect of climate change on contemporary world.
→ an increase in hunger and water crises.
→ health risks through rising air temperatures and heat waves.
→ increasing spread of pests and pathogens
→ loss of biodiversity.
→ melting of the polar caps.
→ El Nino and La-Nino effect.
→ Frequently cyclonic effect on coastal areas, etc.

9th Class Social 4th Lesson Atmosphere Important Questions and Answers

Question 1.
What is Coriolis effect?
Answer:
Because of the impact of Earth’s rotation on its own axis, the winds move slightly to the right in the northern hemisphere, and to the left in the southern hemisphere. This effect is called Coriolis effect.

Question 2.
About which layer do we have very little knowledge?
Answer:
Exosphere is the upper most layer of the atmosphere. This is the highest layer. Very little is known about it.

Question 3.
Why does the amount of water vapour decrease rapidly with altitude?
Answer:
The water vapour is attracted towards the surface or close to the surface due to the gravitational pull of the earth. Hence the amount of water vapour decreases with altitude.

Question 4.
Name and explain the classification of winds.
Depending upon the wind speed, their features, their directions, the way they occur, winds are classified into three types.
A) Planetary winds –
present on the planet as a whole through out the year, that blow continuously and regularly.

B) Seasonal winds –
Restricted to regions or seasonal in character like monsoons.

C) Local winds –
These blow due to local variation in the temperature and pressure, and influence a very small area.

Question 5.
What is a ‘rain shadow’ region?
Answer:

• The moist air is forced to rise over mountain.
• It gives heavy precipitation on the windward side.
• After that the air, which is devoid of moisture blows over leeward side.
• It does not give rain there. So this dry region is known as ‘rain-shadow’ region.

Question 6.
Discuss the cloud formation and various clouds.
Answer:

• Water vapour in the atmosphere attracts dust particles and condense as droplets.
• These droplets in millions and millions together appear like clouds.
• Clouds are different types based on their forms and heights.
• For examples, Cirrus clouds (at higher level), Cumulus clouds (at middle level), Stratus (at lower level) and nimbus (rain bearing and vertical clouds).

Question 7.
How many pressure belts do we have? And what are they?
Answer:
There are seven pressure belts on the earth’s surface. They are :

1. The equatorial low-pressure belt. (1)
2. The sub-tropical high pressure belts. (2)
3. The sub-polar low pressure belts. (2)
4. The polar high pressure belts. (2)

Question 8.
What is relative humidity?
Answer:
The realtive humidity is the ratio between

• The maximum water vapour that the air can hold and
• The actual amount of water vapour it holds.

Question 9.
What are planetary winds? How many types of winds are there?
Answer:
The winds that blow constantly, regularly above the world’s pressure belts are known as planetary winds. They are of three types :

1. Trade winds
2. Westerlies
3. Polar winds.

Question 10.
Write about local winds.
Answer:
The local winds blow due to local variation in the temperature of the area.
These winds are of two types. They are :
1. Hot local winds
2. Cold local winds.

1. Hot local winds :
Hot local winds raise the temperature of the area.

2. Cold local winds :
Cold local winds sometimes bring the temperature of the local area below the freezing points.
Ex : Mistral, Puna, Pampero, etc.

Question 11.
What is NASA?
Answer:
The space agency of USA is NASA, i.e., the National Aeronautics and Space Administration.

Question 12.
“The wind flows from high pressure areas to low pressure areas” – interpret the statement.
Answer:

• When any part of the earth heats up and causes low pressure, it means that there is more vacant space and less molecules.
• Now air from other parts where the pressure is higher moves towards this vacant place.
• It is not difficult for the wind to move along the earth’s surface and thus need not go too much against gravity any more.
• That is why the wind flows from high pressure areas to low pressure areas.

Question 13.
“Heat and pressure – If one increases the other decreases – this is called an inverse relationship” – Interpret the statement.
Answer:

• Due to the heating of the earth’s surface, the gas molecules are heated up, they get a lot of energy and start moving very fast.
• The pressure increases as the molecules will be pushing the object more.
• The energised molecules start flying off higher and higher.
• Now they have more energy to defy the pull of the earth.
• When more molecules go to higher reaches of the atmosphere, the place near the earth has less molecules, this means less pushing around or less pressure.
• Thus when it gets hot, the air pressure becomes low and when it becomes cool, the pressure increases.
• In simpler terms “If one increases the other decreases”-this is called an inverse relationship.

Question 14.
Nowadays there is great demand for energy. Conventional energy sources are depleting quickly. In the light of this, assess wind as alternate energy?
Answer:

• Nowadays there is great demand for energy and conventional energy sources are depleting quickly.
• In these situation wind energy is definitely an alternate energy source.
• Winds like planetary, which blow constantly and regularly are of great help in energy production.
• Wind energy is not an exhausting one like conventional resources.
• Winds of other nature like monsoon and local winds also come handy in energy production.

Question 15.
Observe the figure and answer the questions that follow.

1. To which pressure belts are the westerlies blowing?
Answer:
The westerlies are blowing towards sub-polar low pressure belts.

2. To which pressure belts are the easterlies blowing?
Answer:
The easterlies are blowingtowards sub-polar low pressure belts.

3. What are the winds that are blowing towards the equatorial Sow pressure belts?
Answer:
Trade winds are blowing towards the equatorial low pressure belts.

4. What is the other name for the equatorial low pressure belts?
Answer:
The equatorial low pressure belts are also known as “the equatorial doldrums” or ITCZ i.e., Inter-Tropical Convergence Zone.

5. Towards which direction (right or left) are the planetary winds blowing?
Answer:
The winds in the Northern hemisphere are deflecting towards right and the winds in the southern hemisphere are deflecting towards left due to coriolis effect.

Question 16.
Appreciate the role of winds in weather and climate patterns. Draw a parallel from history.
Answer:

• Winds play a very important role in the weather and climate patterns around the world.
• They have also played a very important role in history.
• For example, Vasco da Gama found sea route to India using winds to power his ships.
• He was able to transport and trade in spices with help of these winds.
• These winds are crucial for Portugese to rule over Goa.

Question 17.
Explain the measures to be taken to mitigate the cyclones.
Answer:

• Early warning systems are needed to be installed by the government.
• Government should inform people in advance about the possibility of disasters like cyclones.
• Government shall provide people with longterm security like strong roads, safe pucca houses for people of low land areas.
• Food, water and medical emergency teams should be kept ready whenever there is a forecast of cyclone.
• Close cooperation between people, Non-Governmental organizations and Government organizations are essential to mitigate cyclone affects.