Question

A bolt of mass 0.3 kg falls the celling of an elevator moving down with a uniform speed of 7ms^-1. It hits the floor of the elevator (length of elevator = 3m) and does not rebound. What is the heat produced by the impact? Would your answer be different if the elevator were stationary?

Answer 1

Potential energy of bolt = mgh = 0.3 × 9.8 × 3 = 8.82 J. 

Since the bolt does not rebound, the while energy is converted into heat. Since the value of acceleration due to gravity is the same in all inertial systems, the answer will not change even if the elevator is stationary.