Newton s Law of Restitution #8211; When two objects are in direct (head #8211; on) impact, the speed with which they separate after impact is usually less than or equal to their speed of approach before impact formulated by Newton is known as Newton s Law of Restitution and can be written in the form Separation speed/Approach speed = e The ratio e is called the coefficient of restitution and is constant for two particular objects. In general [0≤e≤1]