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

hi

the potential energy of  the bolt considering the lift floor as datum is converted into heat energy. therefore answer = mgh.

nw even if the elevator is stationary , then also answer wud be the same as the change in energy is still the same . although initial and final kinetic energies are diff, but the change in kinetic energies are the same.