Question

Professional baseball pitchers can deliver a pitch which can reach the blazing speed of 100 mph (miles per hour). A local team has reach drafted an up-and-coming left handed pitcher who can consistently throw at 90.00 mph. Assuming the ball has a mass 142.8 g and has this speed just before a batter would make contact, how much kinetic energy does the ball have? How high would the ball need to be dropped from to attain the same energy (neglect air resistance)? (The acceleration due to gravity is 9.81 m/s^2.)

Answer 1

We know that the kinetic energy = (1/2)mV²
where m is the mass of the ball , V is the velocity of the ball .
m = 142.8 gram = 0.1428 kg
V = 90 mph = 40.2336 m/s
Kinetic energy = (1/2)*(0.1428)*(40.2336)² = 115.578 J
(2) We know that the potential energy = mgh
where m is the mass of the ball , h is height
mgh = 115.578
h = 82.505 m