In the manufacture of steel balls of the type used for ball bearings. it is important that their material properties be to sufficiently uniform. One way to detect gross differences in their material properties is to observe how a ball rebounds when dropped on a hard strike plate. The rebound characteristics of a ball can be assessed via a quantity called the coefficient of restitution(COR). Specifically, if is the component of ball's impact velocity normal to the strike plate, then the COR is given by COR(COR