Elasticity of a Collision

The elasticity of the collision is related to the ratio of the relative velocities of the two colliding objects after and before the collision:

k = (v2f - v1f) / (v1i - v2i)

The elasticity is related to the type of collision as follows:

Type of CollisionElasticity
Super-elastic k > 1
Elastic k = 1
Inelastic k < 1
Completely inelastic k = 0