Question

A bolt of mass 0.3 kg falls from the ceiling of an elevator moving down with an uniform speed of 7 m s⁻¹. 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 stationery?

Answer 1

given, Mass of the bolt, m = 0.3 kg
Speed of the bolt, v = 7 m/s
Length of the elevator, h = 3 m

here,The relative velocity of the bolt with respect to the elevator is zero. So, the potential energy gets converted into heat energy upon impact according to law of conservation of energy.
heat produced by the impact of bolt= potential energy lost by bolt

= mgh

= 0.3 kg × 9.8m/s² × 3m

= 8.82 kgm²/s² or 8.82 J

hence, heat produced by the impact = 8.82J