NEET Physics Energy Conservation of Energy and Momentum MCQs

a) kinetic energy

b) linear momentum

c) potential energy

d) angular momentum

Answer: kinetic energy

Question: A light and a heavy body have equal momentum. Which one has greater K.E.?

a) The lighter body

b) The heavier body

c) Both have equal K.E.

d) Data given is incomplete

Answer: The lighter body

Question:  A particle of mass m has momentum p. Its kinetic energy will be

a)

b)

c)

d)

Answer:

Question: Kinetic energy, with any reference, must be

a) positive

b) zero

c) negative

d) None of these

Answer: positive

Question: Work done by a conservative force is positive if

a) P.E. of the body decreases

b) P.E. of the body increases

c) K.E. of the body increases

d) K.E. of the body decreases

Answer:  P.E. of the body decreases

Question: The ...X... energy V(x) of the spring is said to be zero when block and spring system is in the ...Y... position

a) potential, equilibrium

b) kinetic, equilibrium

c) mechanical, equilibrium

d) vibrational, left

Answer: potential, equilibrium

Question:  For a conservative force in one dimension, potential energy function V(x) is related to the force F(x) as

a)

b)

c)

d)

Answer:

Question: If stretch in a spring of force constant k is tripled then the ratio of elastic potential energy in the two cases will be

a) 9 : 1

b) 1 : 6

c) 3 : 1

d) 1 : 3

Answer: 9 : 1

Question: If a shell fired from a cannon, explodes in mid air, then

a) its total kinetic energy increases

b) its total momentum increases

c) its total momentum decreases

d) None of these

Answer:  its total kinetic energy increases

Question:  Total ....X.... energy of a system is conserved, if the forces, doing work on it, are .....Y..... . Here, X and Y refer to

a) mechanical, conservative

b) conservative, mechanical

c) mechanical, non-conservative

d) kinetic, conservative

Answer: mechanical, conservative

Question:  A bullet is fired and gets embedded in block kept on table. If table is frictionless, then

a) momentum gets conserved

b) potential energy gets conserved

c) kinetic energy gets conserved

d) None of these

Answer: momentum gets conserved

Question: The speed of an object of mass m dropped from an inclined plane (frictionless), at the bottom of the plane, depends on

a) height of the plane above the ground

b) angle of inclination of the plane

c) mass of the object

d) All of these

Answer:  height of the plane above the ground

Question: One man takes 1 min. to raise a box to a height of 1 metre and another man takes 1/2 min. to do so. The energy of the

a) two is same

b) second is more

c) two is different

d) first is more

Answer: two is same

Question: If the momentum of a body is increased by 50%, then the percentage increase in its kinetic energy is

a) 125%

b) 200%

c) 100%

d) 50%

Answer:  125%

Question:  A metallic wire of length L metre extends by l metre when stretched by suspending a weight Mg from it. The mechanical energy stored in the wire is

a)

b)

c)

d)

Answer:

Question: A ball dropped from a height of 2m reaches to a height of 1.5m before hitting the ground. Then the percentage of potential energy lost is

a) 25

b) 30

c) 50

d) 100

Answer:  25

Question:  A body starts from rest and acquires a velocity V in time T. The work done on the body in time t will be proportional to

a)

b)

c)

d)

Answer:

More Questions..............................................

Question: A body of mass 0.5 kg travels in a straight line with velocity v = 5x^3/2. The work done by the net force during the displacement from x = 0 to x = 2m is

a) 50 J

b) 75 J

c) 100 J

d) 25 J

Answer: 50 J

Question: Four particles given, have same momentum. Which has maximum kinetic energy

a) Electron

b) Proton

c) None of these

d) Deutron

Answer: Electron

Question: The potential energy of a system increases if work is done

a) upon the system by a conservative force

b) upon the system by a non conservative force

c) by the system against a non conservative force

d) by the system against a conservative force

Answer: upon the system by a conservative force

Question: If two particles are brought near one another, the potential energy of the system will

a) increase

b) remains the same

c) decrease

d) equal to the K.E

Answer:  increase

Question:

a) I, III and IV

b) I and II

c) I, II and IV

d) I, II, III and IV

Answer: I, III and IV

Question: The K.E. acquired by a mass m in travelling a certain distance d, starting form rest, under the action of a constant force is directly proportional to

a) independent of m

b) m

c)

d)

Answer:   independent of m

Question:  A running man has half the kinetic energy of that of a boy of half of his mass. The man speeds up by 1m/s so as to have same K.E. as that of the boy. The original speed of the man will be

a)

b)

c)

d)

Answer:

Question:   A steel ball of mass 5g is thrown downward with velocity 10 m/s from height 19.5 m. It penetrates sand by 50 cm. The change in mechanical energy will be (g = 10 m/s²)

a) 1.25 J

b) 1.5 J

c) 1.75 J

d) 1J

Answer:  1.25 J

Question:

a) CD

b) BC

c) AB

d) OA

Answer: CD

Question:  A ball is allowed to fall from a height of 10 m. If there is 40% loss of energy due to air friction, then velocity of the ball when it hit the ground is

a)

b)

c)

d)

Answer:

Question: In the non-relativistic region, if the momentum, is increase by 100% , the percentage increase in kinetic energy is

a) 300

b) 400

c) 200

d) 100

Answer: 300

Question:  Two bodies A and B having masses in the ratio of 3 : 1 possess the same kinetic energy. The ratio of linear momentum of B to A is

a)

b)

c) 3 : 1

d) 1 : 3

Answer:

Question:  A particle is placed at the origin and a force F = kx is acting on it (where k is positive constant). If U(0) = 0, the graph of U(x) versus x will be (where U is the potential energy function) :

a)

b)

c)

d)

Answer:

Question:  Figure shows a bob of mass m suspended from a string of length L. The velocity is V₀ at A, then the potential energy of the system is _______ at the lowest point A.

a) zero

b) mgh

c)

d)

Answer:  zero

Question:  Calculate the K.E and P.E. of the ball half way up, when a ball of mass 0.1 kg is thrown vertically upwards with an initial speed of 20 ms^–1.

a) 10 J, 10 J

b) 10 J, 20 J

c) 15 J, 8 J

d) 8 J, 16 J

Answer:  10 J, 10 J

Question: A small body is projected in a direction inclined at 45º to the horizontal with kinetic energy K. At the top of its flight, its kinetic energy will be

a) K/2

b) Zero

c) K/4

d) None of these

Answer:  K/2

Question:

a) 10s

b) 12s

c) 8s

d) 4s

Answer: 10s

Question: A bomb of mass 9 kg explodes into the pieces of masses 3 kg and 6 kg. The velocity of mass 3 kg is 16 m/s. The kinetic energy of mass 6 kg in joule is

a) 192

b) 768

c) 384

d) 96

Answer: 192

Question: An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

a) 2,000 J - 5, 000 J

b) 2 × 10⁵ J - 3 × 10⁵ J

c) 200 J - 500 J

d) 20, 000 J - 50,000 J

Answer: 2,000 J - 5, 000 J

Question:  At time t = 0s particle starts moving along the x-axis. If its kinetic energy increases uniformly with time t, the net force acting on it must be proportional to

a)

b)

c) constant

d) t

Answer:

Question: Two bodies of masses 4 kg and 5 kg are moving with equal momentum. Then the ratio of their respective kinetic energies is

a) 5 : 4

b) 1 : 3

c) 2 : 1

d) 4 : 5

Answer:  5 : 4

Question:  A crate is pushed horizontally with 100 N across a 5 m floor. If the frictional force between the crate and the floor is 40 N, then the kinetic energy gained by the crate is

a) 300 J

b) 250 J

c) 240 J

d) 200 J

Answer: 300 J

Question: A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement x is proportional to

a) x²

b) e^x

c) x

d) log_e x

Answer:  x²

Question:

a)

b)

c)

d)

Answer:

Question:

a) 0.5 kg

b) 0.15 kg

c) 0.12 kg

d) 1.5 kg

Answer: 0.5 kg

Question: A 2 kg block slides on a horizontal floor with a speed of 4m/s. It strikes a uncompressed spring, and compresses it till the block is motionless. The kinetic friction force is 15N and spring constant is 10,000 N/m. The spring compresses by

a) 5.5 cm

b) 2.5 cm

c) 11.0 cm

d) 8.5 cm

Answer: 5.5 cm

Question:

a) E/2

b) E/8

c) 2E

d) E

Answer: E/2

Question: Two springs have their force constant as k₁ and k₂ (k₁ > k₂). When they are stretched by the same force

a) more work is done in case of second spring

b) more work is done in case of first spring

c) equal work is done in case of both the springs

d) no work is done in case of both the springs

Answer:  more work is done in case of second spring

Question: One end of a light spring of spring constant k is fixed to a wall and the other end is tied to a block placed on a smooth horizontal surface. In a displacement, the work done by the spring is 1/2 k x². The possible cases are

a) the spring was initially compressed by a distance x, was finally in its natural length

b) it was initially stretched by a distance x and was finally in its natural length

c) it was initially in its natural length and finally in a compressed position

d) it was initially in its natural length and finally in the stretched position

Answer: the spring was initially compressed by a distance x, was finally in its natural length

Question: If the extension in a spring is increased to 4 times then the potential energy

a) becomes 16 times

b) becomes 4 times

c) remains the same

d) becomes one fourth

Answer:  becomes 16 times

Question: A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m. It rolls down a smooth surface to the ground, then climbs up another hill of height 30 m and finally rolls down to a horizontal base at a height of 20 m above the ground. The velocity attained by the ball is

a) 40 m/s

b) 20 m/s

c) 10 m/s

d) None of these

Answer: 40 m/s

Question: A long string is stretched by 2 cm and the potential energy is V. If the spring is stretched by 10 cm, its potential energy will be

a) 25 V

b) 5 V

c) V/5

d) V / 25

Answer: 25 V

Question: The potential energy of a conservative system is given by U = ay² – by, where y represents the position of the particle and a as well as b are constants. What is the force acting on the system ?

a) b – 2ay

b) 2ay – b

c) None of these

d) – ay

Answer:  b – 2ay

Question:

a) 0.6 J

b) 0.8 J

c) 1.5 J

d) 0.3 J

Answer: 0.6 J

Question: Figure here shows the frictional force versus displacement for a particle in motion. The loss of kinetic energy in travelling over s = 0 to 20 m will be

a) 225 J

b) 200 J

c) 250 J

d) 750 J

Answer:  225 J

Question:  The kinetic energy of particle moving along a circle of radius R depends upon the distance covered S and is given by K = aS where a is a constant. Then the force acting on the particle is

a)

b)

c)

d)

Answer:

Question: A body falls freely under gravity. Its velocity is v when it has lost potential energy equal to U. What is the mass of the body?

a) 2U/v²

b) U /v²

c) 2U²/v²

d) U²/v²

Answer:  2U/v²

Question:

a)

b)

c)

d)

Answer: