AP 9th Class Physical Science Bits Chapter 10 Work and Energy with Answers

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AP State Syllabus 9th Class Physical Science Bits 10th Lesson Work and Energy with Answers

Question 1.
The conditions need to be satisfied in order to say that work has been done are
A) a force should act on the object
B) the object must be displaced
C) both A and B
D) no condition is required
Answer:
C) both A and B

Question 2.
Work is ………………. quantity.
A) vector
B) scalar
C) unit less
D) can’t say
Answer:
B) scalar

Question 3.
The formula W = Fs is used in only ………………. motion of the object.
A) circular
B) oscillatory
C) translatory
D) trajectory
Answer:
C) translatory

Question 4.
If positive work is done on a system, its energy
A) decreases
B) increases
C) becomes zero
D) remains same
Answer:
B) increases

Question 5.
The kinetic energy of an object depends on
A) mass
B) speed
C) gravitational force
D) none
Answer:
C) gravitational force

Question 6.
The potential energy of an object increases with its
A) height or position
B) mass
C) velocity
D) none
Answer:
A) height or position

Question 7.
The sum of kinetic energy and the potential energy of an object is called its
A) total energy
B) mechanical energy
C) system of energy
D) energy conservation
Answer:
B) mechanical energy

Question 8.
Rate of doing work or rate of transfer of energy is
A) work
B) energy
C) power
D) time
Answer:
C) power

Question 9.
The measure of speed of the work done is
A) power
B) energy
C) work
D) time
Answer:
A) power

Question 10.
The capacity to do a work is called
A) energy
B) power
C) work
D) strength
Answer:
A) energy

Question 11.
Work is equal to the product of ……………….. and …………………
A) force, time
B) force, displacement
C) force, velocity
D) force, acceleration
Answer:
B) force, displacement

Question 12.
Among these which is a scalar quantity ………………..
A) velocity
B) acceleration
C) momentum
D) work
Answer:
D) work

Question 13.
S.I. Unit of work is ………………….
A) Erg
B) Joule
D) Pascal
C) Newton
Answer:
B) Joule

Question 14.
1 N – m is equal to ……………….
A) Erg
B) Newton
C) Pascal
D) Joule
Answer:
D) Joule

Question 15.
In case of a vertically up thrown body, the speed of the body while moving up ……………….
A) increases
B) decreases
C) no change
D) both A & B
Answer:
B) decreases

Question 16.
If work has positive value, the body on which the work has been done would energy.
A) gain
B) lose
C) no change in
D) none of these
Answer:
A) gain

Question 17.
If work has negative value, the body on which the work has been done would ………………. energy.
A) gain
B) lose
C) without change
D) none of these
Answer:
B) lose

Question 18.
The capacity of doing work by an object depends on ………………. and of the object which is doing work.
A) position, state
B) length, breadth
C) area, volume
D) pressure, density
Answer:
A) position, state

Question 19.
When work is done, energy will be ……………… from one object to other.
A) transferred
B) lost
C) gained
D) none of these
Answer:
A) transferred

Question 20.
The biggest natural and primary source of energy for us is the ………………….
A) Moon
B) Jupiter
C) Sun
D) Mars
Answer:
C) Sun

Question 21.
The energy possessed by an object due to its motion is called ……………… energy.
A) potential
B) kinetic
C) mechanical
D) electrical
Answer:
B) kinetic

Question 22.
The numerical expression for kinetic energy is K.E. = ………………….
A) \(\frac{1}{2}\) mv
B) \(\frac{1}{2}\) mv²
C) \(\frac{\mathrm{mv}^{2}}{\mathrm{r}}\)
D) \(\frac{1}{2}\)m²v
Answer:
B) \(\frac{1}{2}\) mv²

Question 23.
P.E. = …………………
A) \(\frac{1}{2}\) mv²
B)\(\frac{1}{2}\) mv
C) mgh
D) \(\frac{\mathrm{mg}}{\mathrm{h}}\)
Answer:
C) mgh

Question 24.
In an iron box ……………….. energy converts into ………………… energy.
A) electrical, sound
B) electrical, magnetic
C) electrical, heat
D) electrical, light
Answer:
C) electrical, heat

Question 25.
Power = ……………….
A) \(\frac{\text { Work }}{\text { Time }}\)
B) \(\frac{\text { Time }}{\text { Work }}\)
C) Work × Time
D) None of these
Answer:
A) \(\frac{\text { Work }}{\text { Time }}\)

Question 26.
The unit of power is ……………….
A) Erg
B) Joule/sec.
C) Watt
D) Both B & C
Answer:
D) Both B & C

Question 27.
Kinetic energy of an object increases with its ………………..
A) acceleration
B) speed
C) volume
D) density
Answer:
B) speed

Question 28.
If the displacement of the object is in the direction opposite to the direction of force applied, then the work done is ………………….
A) positive
B) negative
C) 0
D) none of these
Answer:
B) negative

Question 29.
Work (W) = ………………..
A) F / s
B) F × s
C) s / F
D) none of these
Answer:
B) F × s

Question 30.
The capacity to do work is called …………………
A) power
B) work
C) energy
D) force
Answer:
C) energy

Question 31.
Mechanical energy = ……………….
A) PE + KE
B) PE / KE
C) KE / PE
D) PE – KE
Answer:
A) PE + KE

Question 32.
1 Watt = ………………..
A) 1 erg/s
B) 1 J/s
C) 1 Newton/ sec
D) 1 Newton . sec
Answer:
B) 1 J/s

Question 33.
Work done by gravitational force on a freely falling body ………………..
A) negative
B) 0
C) positive
D) both A & C
Answer:
C) positive

Question 34.
Work done by friction on a body moving on plain ground ………………….
A) positive
B) negative
C) 0
D) none of these
Answer:
B) negative

Question 35.
Work done by a porter standing with luggage on his head is …………………….
A) positive
B) negative
C) 0
D) none of these
Answer:
C) 0

Question 36.
When a ball is moving on plain ground, the work done by the frictional force on the ball is
A) positive
B) negative
C) zero
D) undefined
Answer:
B) negative

Question 37.
A boy pushes wall. The work done by the boy is
A) positive
B) negative
C) zero
D) undefined
Answer:
C) zero

Question 38.
Human beings or machines need ………………to do work.
A) energy
B) food
C) petrol
D) fuel
Answer:
A) energy

Question 39.
Work is said to be done in the following case
A) Rangaiah is pushing a huge rock but he fail to move it
B) Seetha is pulling a toy car
C) Priyanka is working hard for her examinations
D) A porter is waiting on the platform of a railway station with luggage on his head.
Answer:
B) Seetha is pulling a toy car

Question 40.
The energy possessed by a wounded spring in a toy car is
A) kinetic energy
B) spring energy
C) muscular energy
D) potential energy
Answer:
D) potential energy

Question 41.
The energy possessed by a running athlete is
A) potential energy
B) kinetic energy
C) muscular energy
D) food energy
Answer:
B) kinetic energy

Question 42.
Energy possessed by the blowing wind is ………………….. energy.
A) potential
B) mechanical
C) kinetic
D) magnetic
Answer:
C) kinetic

Question 43.
The energy possessed by a body due to its height or position is ………………… energy.
A) potential
B) kinetic
C) mechanical
D) muscular
Answer:
A) potential

Question 44.
The sum of the kinetic energy and the potential energy of an object is called its ……………………. energy.
A) muscular
B) electric
C) magnetic
D) mechanical
Answer:
D) mechanical

Question 45.
The total mechanical energy of an aeroplane at rest is ………………….
A) mgh
B) \(\frac{1}{2}\) mv²
C) zero
D) cannot say
Answer:
C) zero

Question 46.
In fuels like petroleum, coal, etc ……………… energy is stored in them.
A) physical
B) electrical
C) magnetical
D) chemical
Answer:
D) chemical

Question 47.
Ratio of doing work or rate of transfer of energy is defined as ……………….
A) work
B) power
C) capacity
D) impulse
Answer:
B) power

Question 48.
In case of a freely falling body ……………… energy is gradually converted into …………………. energy at a certain height ‘h’.
A) potential, kinetic
B) kinetic, potential
C) kinetic, kinetic
D) potential, potential
Answer:
A) potential, kinetic

Question 49.
The water stored in overhead tanks, possesses ………………. energy.
A) mechanical
B) kinetic
C) potential
D) chemical
Answer:
C) potential

Question 50
…………….. energy is used by plants for preparing their food.
A) Potential
B) Kinetic
C) Mechanical
D) Solar
Answer:
D) Solar

Question 51.
Work done by force applied by hands of a man swimming in a pond is ………………
A) negative
B) positive
C) 0
D) none of these
Answer:
A) negative

Question 52.
Energy of running water is ……………….. energy.
A) potential
B) kinetic
C) mechanical
D) none of these
Answer:
B) kinetic

Question 53.
Energy of a raised hammer is ……………… energy.
A) potential
B) kinetic
C) mechanical
D) magnetic
Answer:
A) potential

Question 54.
‘Work’has
A) Only direction, no magnitude
B) Only magnitude, no direction
C) Both magnitude and direction
D) No magnitude, no direction
Answer:
B) Only magnitude, no direction

Question 55.
Power is defined as
P) rate of doing work
Q) rate of transfer of energy
R) sum of kinetic and potential energy
A) P only
B) Q and R
C) P and Q
D) P, Q and R
Answer:
C) P and Q

Question 56.
When speed of the ball is doubled its kinetic energy is
A) Remains same
B) Gets doubled
C) Becomes half
D) Becomes 4 times
Answer:
D) Becomes 4 times

Question 57.
Chaitanya performs 300J of work in 5 minutes. The power delivered by her is
A) 60 W
B) \(\frac{1}{60}\) W
C) 1 W
D) 0 W
Answer:
C) 1 W