# Kinetic energy with no velocity

When a body is displaced against the gravitational field of force it gains potential energy. When we drop the body it begins to move downward with a certain amount of acceleration, and the potential energy turns into kinetic energy. Kinetic energy is given by the equation: $$E_k = \frac{1}{2}mv^2$$ When the body falls off the ground, and it stops moving then its velocity is zero, and therefore the kinetic energy is also zero in this case. In which form of energy does this kinetic energy usually convert into?

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It is zero, because kinetic energy is the one associated only with an object in motion. It is maximum just before it touches the ground. And once it reaches the ground, most of the energy is perceived as sound, lost as heat and some as stress, which causes deformation of the body. If the body can't sustain the stress on its impact with the ground, it breaks.

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thanks, I was expecting the same answer! :) –  Samama Fahim Mar 25 '13 at 18:41