Impulse and Momentum An impulsive force is a large force exerted over a short time interval, like that of a racket hitting a ball. Momentum is equal to the product of the mass of an object and its velocity or p=mv, p being momentum and v and m being mass and velocity. Impulse is the change in momentum of an object as that object is acted upon by an outside force or a time interval or period of time. Derived from these two ideas is the impulse momentum theorem which tells us that an impulse delivered to an object will change its momentum and the momentum after a collision is equal to the momentum before plus the impulse that arises.                                                                            https://www.pinterest.com/pin/462604192944067115/                                                      http://blog.naturessunshine.com/en/racquetball-much-better-know-rules/   A racket colliding with a ball exerts a force on the ball and the racket. The ball doesn't immediately rebound from the racket there is a time interval in which the ball deforms flattening against the racket and strings stretch back against the impact of the ball. It is at this point of maximum deformation the maximum amount of force is exerted on the ball, causing the ball to experience an impulse and rapidly gain momentum..