Assertion (A) : An elevator is going up at constant velocity. If a person in the lift drops a coin in the elevator, then the coin will fall with uniform velocity. Reason (R) : The elevator is not moving with any acceleration or retardation.

The Assertion (A) is false because a coin dropped inside an elevator, regardless of the elevator's velocity, is subject to the force of gravity. Once released, the only significant force acting on the coin is its weight, causing it to accelerate downwards at approximately 9.8 m/s² relative to an inertial frame [c3]. Therefore, it falls with increasing speed (acceleration), not uniform velocity [c2][c3]. The Reason (R) is true; an elevator moving at constant velocity has zero acceleration [t2][t5]. In such an inertial frame, the motion of the coin relative to the observer inside the lift is identical to its motion if the lift were at rest [t2][t4]. Since a coin dropped from rest in a stationary room accelerates downwards, it will similarly accelerate downwards in a lift moving at constant velocity [t6].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 8: Measurement of Time and Motion > 8.4 Uniform and Non-uniform Linear Motion > p. 117
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.8: Let us observe > p. 72