A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m

cbse
workandenergy

#1

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


#2

Here mass of bolt, m = 0.3 kg, height through which bolt falls h = 3 m.
When the bolt falls on floor of elevator and does not rebound, it suffers a loss of potential energy
∆U = mgh = 0.3 x9.8 x3 = 8.82 J
.‘.Amount of heat produced = Loss of potential energy = 8.82 J, because there is no gain in KE at all.