When bodies stick together after the collision, then collision is perfectly inelastic. If after collision of two bodies, the total kinetic energy of the bodies remain the same as before collision, then it is perfectly elastic collision. Kinetic energy and momentum both are conserved. Collision of two glass balls is an example of perfectly elastic collision. When two bodies stick together after the collision, then the collision is said to be perfectly inelastic collision. In this collision most of the kinetic energy of the bodies is lost in other forms. Hence, kinetic energy is not conserved but total energy is conserved. Man jumping on cart and bullet embedded in block are examples of inelastic collision.