A bolt of mass 0.2 kg falls from the ceiling of an elevator moving down with an uniform speed of 5 ms-1. It hits the floor of the elevator (length of the elevator = 5 m) and does not rebound. The amount of heat produced by the impact is (Take g = 10 ms-2)

Here, m=0.2kg, v=5ms−1h = length of elevator = 5 mAs relative velocity of the bolt w.r.t. elevator is zero, therefore, in the impact, only potential energy of the bolt is converted into heat energy. Amount of heat produced= Potential energy lost by the bolt = mgh=(0.2kg)10ms−2(5m)=10J