Coefficient of restitution

In physics, the coefficient of restitution (COR, also denoted by e), can be thought of as a measure of the elasticity of a collision between two bodies. It is a dimensionless parameter defined as the ratio of the relative velocity of separation after a two-body collision to the relative velocity of approach before collision. In most real-word collisions, the value of e lies somewhere between 0 and 1, where 1 represents a perfectly elastic collision (in which the objects rebound with no loss of speed but in the opposite directions) and 0 a perfectly inelastic collision (in which the objects do not rebound at all, and end up touching). The basic equation, sometimes known as Newton's restitution equation was developed by Sir Isaac Newton in 1687.^[1]$${\displaystyle {\text{Coefficient of restitution }}(e)={\frac {\left|{\text{Relative velocity of separation after collision}}\right|}{\left|{\text{Relative velocity of approach before collision}}\right|}}}$$