Statement I : In an elastic collision of two bodies, the momentum and energy of each body is conserved.Statement II : If two bodies stick to each other, after colliding, the collision is said to be perfectly elastic.

In an elastic collision both the momentum and kinetic energy remains conserved. But this rule is not for individual bodies, but for the system of bodies before and after the collision. While collision in which there occurs some loss of kinetic energy is called inelastic collision. Collision in daily life are generally inelastic. The collision is said to be perfectly inelastic, if two bodies stick to each other.