Energy question?

Question

A child can throw a baseball at 20mph some professional ball players can throw a baseball at 100mph which is five times as fast. How much more energy does the pro ball player give to the faster ball

Answer 1

Simple, use Kinetic Energy = 1/2 x mass x velocity^2

20 mph = 8.3333... metres per second
100 mph = 41.66... metres per second

If we take the mass of the ball to be 0.25 kilograms, then-:

(Child) 1/2 x 0.25 x 8.3333^2 = 8.68 Joules

(Pro) 1/2 x 0.25 x 41.66^2 = 216.95 Joules

In this case approximately 25 times more energy !!!