What is the difference between plastic and elastic collision?

An elastic collision is a collision where objects will bounce after they hit each other. For example balls in a pool game bounce after heating each other. For an elastic collision, Mechanical Energy Kinetic Energy, and Linear Momentum are conserved.

Plastic or inelastic collision involves Energy loss in the collision. For example when two cars hit they are deformed. In this case, kinetic energy is transformed into elastic energy leaving bumps on the car. Therefore, for a plastic collision Kinetic Energy is NOT conserved, but Linear Momentum and Mechanical energy are conserved.