Elastic Collision

In elastic collision the total kinetic energy of all the bodies under consideration remains constant. The coefficient of restitution for this kind of collision is always 1. The energy is not converted to heat , noise or potential energy but converted to kinetic energy itself.
In the example below the kinetic energy is converted to kinetic energy itself. If you check the rotation checkbox the translational kinetic energy will be also converted to rotational kinetic energy.



Inelastic Collision

A perfectly inelastic collision occurs when the maximum amount of kinetic energy of a system is lost. In a perfectly inelastic collision, i.e., a zero coefficient of restitution, the colliding particles stick together. In such a collision, kinetic energy is lost by bonding the two bodies together. This bonding energy usually results in a maximum kinetic energy loss of the system. It is necessary to consider conservation of momentum.

Partially Inelastic Collision

In real world with exceptions of very few , all the collisions are of this type. In partially inelastic collision the body's kinetic energy gets reduced by a certain amount. This quantity which defines this amount is known as coefficient of restitution. It decides what part of energy the colliding body will give to another body.