NEET Physics Work Energy and Power MCQs Set A

Question. A proton is kept at rest. A positively charged particle is released from rest at a distance d in its field. Consider two experiments; one in which the charged particle is also a proton and in another, a positron. In the same time t, the work done on the two moving charged particles is
(a) more for the case of a positron, as the positron moves away a larger distance
(b) less for the case of a positron, as the positron moves away more rapidly and the force on it weakens
(c) same as the same force law is involved in the two experiments
(d) same as the work done by charged particle on the stationary proton

Answer: A

Question. A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is
(a) at first greater than mg and later becomes equal to mg
(b) variable but always greater than mg
(c) constant and greater than mg in magnitude
(d) constant and equal to mg in magnitude

Answer: A

Question. A bicyclist comes to a skidding stop in 10 m. During this process, the force on the bicycle due to the road is 200N and is directly opposed to the motion. The work done by the cycle on the road is
(a) zero
(b) + 2000 J
(c) – 200 J
(d) – 20,000 J

Answer: A

Question.  A body is falling freely under the action of gravity alone in vaccum. Which of the following quantities remain constant during the fall?
(a) Total mechanical energy
(b) Total linear momentum
(c) Potential energy
(d) Kinetic energy

Answer: A

Question.  During inelastic collision between two bodies, which of the following quantities always remain conserved?
(a) Total linear momentum
(b) Speed of each body
(c) Total mechanical energy
(d) Total kinetic energy

Answer: A

Question.  In a shotput event an athlete throws the shotput of mass 10 kg with an initial speed of 1 m s^–1 at 45° from a height 1.5 m above ground. Assuming air resistance to be negligible and acceleration due to gravity to be 10 m s^–2, the kinetic energy of the shotput when it just reaches the ground will be
(a) 155.0 J
(b) 5.0 J
(c) 52.5 J
(d) 2.5 J

Answer: A

Question.   A cricket ball of mass 150 g moving with a speed of 126 km/ h hits at the middle of the bat, held firmly at its position by the batsman. The ball moves straight back to the bowler after hitting the bat. Assuming that collision between ball and bat is completely elastic and the two remain in contact for 0.001s, the force that the batsman had to apply to hold the bat firmly at its place would be
(a) 1.05 × 10⁴ N
(b) 10.5 N
(c) 21 N
(d) 2.1 × 10⁴ N

Answer: A

Question.  If the linear momentum is increased by 5%, the kinetic energy will increase by
(a) 10%
(b) 100%
(c) 50%
(d) 125%

Answer: A