#### 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 = (v_{2f} - v_{1f}) / (v_{1i} - v_{2i})

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

Type of Collision | Elasticity |

Super-elastic | k > 1 |

Elastic | k = 1 |

Inelastic | k < 1 |

Completely inelastic | k = 0 |