Suppose a ball is dropped from \(2.5 \mathrm{~m}\) and rebounds to \(1.4 \mathrm{~m}\).

a. How fast is the ball moving just before it hits the floor?

b. What is the ball's speed just after leaving the floor?

c. What happens to the "lost" energy?

d. If the time of the collision with the floor is \(6.0 \mathrm{~ms}\), what is the average force on the ball during the impact?

Tennis balls are tested by being dropped from a height of \(2.5 \mathrm{~m}\) onto a concrete floor. The \(57 \mathrm{~g}\) ball hits the ground, compresses, then rebounds. A ball will be accepted for play if it rebounds to a height of about \(1.4 \mathrm{~m}\); it will be rejected if the bounce height is much more or much less than this.