ABSTRACT
The different contact times and contact forces in these examples indicate that the nature of impact is dependent on both objects involved in the collision. Generally speaking, the softer the object the longer the impact takes and the lower the force generated. In order to understand the specific nature of impact it is necessary to consider the conservation of momentum and the coefficient of restitution relationships. These lead to two equations which are known as the impact
The conservation The conservation of momentum (see also section B4) is an important law in of momentum science that defines how objects behave when they interact. The law applies to a
system that may contain many objects but for the purpose of this text the interaction between just two objects will be considered. These two objects can represent, for example, the head and ball in soccer heading, or the ball and racket in tennis, or the club and ball in golf. In other words, they represent the general situation of a collision in sport.
