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# CLASS: IX :: Work and Energy

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CLASS: IX NCERT (CBSE)
PHYSICS
Work and Energy

Question (1): Work done = Force x _______

1. distance
2. acceleration
3. velocity
4. speed
Ans: 1

Question (2): 1 joule = 1 _______

1. N m2
2.
3. N m
4. N2 m2
Ans: 3
Question (3): Which form of energy does the flowing water possess?

1. gravitational energy
2. potential energy
3. electrical energy
4. kinetic energy
Ans: 4

Question (4): A body of mass 2 kg is dropped from a height of 1m. Its kinetic energy as it touches the ground is _______

1. 19.6 N
2. 19.6 J
3. 19.6 kg
4. 19.6 m
Ans: 2
Question (5): The unit of power is _______

1. watt per second
2. joule
3. kilojoule
4. joule per second
Ans: 4
Question (6): 3730 watts = ______h.p.

1. 5
2. 2
3. 746
4. 6
Ans: 1

Question (7): A coolie carries a load of 500 N to a distance of 100 m. The work done by him is

1. 5 N
2. 50,000 Nm
3. 0
4. 1/5 N
Ans: 3

Question (8): The P.E. of a body at a certain height is 200 J. The kinetic energy possessed by it when it just touches the surface of the earth is

1. > P.E.
2. < P.E.
3. = P.E.
4. cannot be known
Ans: 1
Question (9): Power is a measure of the _______
1. rate of change of momentum
2. force which produces motion
3. change of energy
4. rate of change of energy
Ans: 4
Question (10): Two objects of masses 1 x 10-3 kg and 4 x 10-3 kg have equal momentum. What is the ratio of their kinetic energies?

1. 4:1
2. 2:1
3. 16:1
4.
Ans: 1
Question (11): A 40 newton object is released from a height of 10 m. Just before it hits the ground, its kinetic energy, in joules is _______

1. 400
2. 3920
3. 2800
4. 4000
Ans: 1
Question (12): If the speed of an object is doubled then its kinetic energy is _______

1. doubled
3. halved
4. tripled
Ans: 2
Question (13): 1.5 kW = ______ watts

1. 1500
2. 150
3. 15000
4. 15
Ans: 1
Question (14): A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is (g = 10 m/s2)
1. 50 J
2. 60 J
3. 500 J
4. 600 J
Ans: 3
Question (15): The type of energy possessed by a simple pendulum, when it is at the mean position is
1. kinetic energy
2. potential energy
3. potential energy + kinetic energy
4. sound energy
Ans: 1
Question (16): An iron sphere of mass 30 kg has the same diameter as an aluminium sphere whose mass is 10.5 kg. The spheres are dropped simultaneously from a cliff. When they are 10 m from the ground, they have the same _______.

1. acceleration
2. momentum
3. potential energy
4. kinetic energy
Ans: 1

Question (17): A 1 kg mass has a kinetic energy of 1 joule when its speed is
1. 0.45 m/s
2. 1 m/s
3. 1.4 m/s
4. 4.4 m/s
Ans: 3
Question (18): If air resistance is negligible, the sum total of potential and kinetic energies of a freely falling body _______

1. increases
2. decreases
3. becomes zero
4. remains the same
Ans: 4

Question (19): Name the physical quantity which is equal to the product of force and velocity.

1. work
2. energy
3. power
4. acceleration
Ans: 3

Question (20): An object of mass 1 kg has potential energy of 1 joule relative to the ground when it is at a height of _______.

1. 0.102 m
2. 1 m
3. 9.8 m
4. 32 m
Ans: 1

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