Answer
2230 N.
Work Step by Step
Let the direction from the batter to the pitcher be the positive direction. Calculate the constant force from the ball’s change in momentum, equation 7-4.
$$F=m\frac{\Delta v}{\Delta t}=(0.145 kg)\frac{46.0 m/s – (-31.0 m/s)}{5.00 \times 10^-3 s}=2230 N$$
The answer is rounded to 3 significant figures.