Example: A Baseball Pitch

What is the acceleration of a fastball?

A baseball pitcher throws a fast ball. The ball goes from rest to a speed of 50m/s in his hand. His throwing action covers a distance of two meters. Find the acceleration of the ball, assuming it is constant.

We have a=(v²-v₀²)/2(x-x₀) = 625m/s² ~ 70 gravities!

We can make a dimensional analysis of the terms in (5) to check that they are consistent:

[v²]=L²/T²=[v₀²];
[a₀x]=(L/T²)*L OK