A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?

Hint
As we know already that the energy in this universe can never be created nor destroyed. So, the energy can be transferred from one form of the energy of the system to another form of the energy of the system. This can be given by law of conservation of energy.

Complete step by step answer
When an object is placed in some height it must have some potential energy. And this block is allowed to fall freely due to the acceleration due to gravity, then the potential energy of the object can be changed to the kinetic energy of the object. The potential energy of the object depends on the mass of the object, acceleration due to gravity of the object and the height of the object is placed. The kinetic energy of the object is depending on the mass of the object and the velocity of the object which the object is moving.
When the object falls from some height the potential energy of the object decreases and the kinetic energy of the object increases. At that instant when the object touches the ground, the total potential energy of the object gets converted to kinetic energy. After the object hits well on the ground the kinetic energy is converted into heat energy and sound energy, this is the reason for sound when the object falls to the ground.

Note
The energy can neither be created nor destroyed. The energy can be transferred from one form to another form. The object is kept in some height, so that the block will have the potential energy, when the block is released, the potential energy of the block is changed to the kinetic energy of the block.