Problem
1. A \( 0.50 \mathrm{~kg} \) football is thrown with a velocity of \( 15 \mathrm{~m} / \mathrm{s} \) to the right. A stationary receiver catches the ball and brings it to rest in \( 0.020 \mathrm{~s} \). What is the force exerted on the ball by the receiver?
Solution
Step 1 ：\(v = u + at \Longrightarrow a = \frac{v - u}{t}\)
Step 2 ：\(a = \frac{0 - 15}{0.020} = -750 \mathrm{~m} / \mathrm{s}^2\)
Step 3 ：\(F = ma = 0.50 \times -750 = -375 \mathrm{~N}\)
