Testing Tennis Balls Tennis balls are tested by being dropped from a height of 2.5m onto a concrete floor. The 57g ball hits the ground, compresses, then rebounds. A ball will be accepted for play if it rebounds to a height of about 1.4m ; it will be rejected if the bounce height is much more or much less than this.
Suppose a ball is dropped from 2.5m and rebounds to 1.6m. How fast is the ball moving just before it hits the floor?