Question

As a protest against the umpire’s calls, a base- ball pitcher throws a ball straight up into the air at a speed of 20 m/s. In the process, he moves his hand through a distance of 1.47 m.
The acceleration of gravity is 9.8 m/s2 .
If the ball has a mass of 0.18 kg, find the force he exerts on the ball to give it this upward speed.
Answer in units of N.

Answer 1

F = m g + m a
average speed in hand = (20 + 0)/2 = 10 m/s
so
time in hand = 1.47 m/10 m/s = .147 seconds

a = change in speed / time in hand = 20/.147

so F = .18(9.8 + 20/.147)

Answer 2

WOW thx