The co-efficient of restitution e for a perfectly elastic collision is _____.

Concept:

The energy dissipation during impact is called by the term, coefficient of restitution, a scalar quantity.

e = (velocity of separation) / (velocity of approach)

e = (v₁ - v₂) / (u₂ - u₁)

where, v = velocity of the body after impact, u = velocity of the body before impact

For perfectly elastic collision, e = 1

For inelastic collision, e < 1

For a perfectly inelastic collision, e = 0

Note:

When two bodies collide, they exchange energy, and obviously the body with the higher energy will transfer some of its energy to the one with lower energy. Hence, the body which had the higher velocity initially will now have the lower velocity.