Experimental study of the gear effect

Abstract

The gear effect arises during the collision of a ball and an extended object due to rotation of the object across the surface of the ball. The effect is well known in golf, drivers being designed with a convex face to help reduce the problem of a mis-hit. An experiment is described to examine the gear effect for two different balls, one with a high tangential coefficient of restitution and one with a low coefficient. The outgoing ball spins were different, indicating that a driver designed for one type of golf ball is unlikely to work well with a different type of golf ball.