A 160 g ball reaches a fielder's hands at 30 m/s, and she stops it…

Step 1. (a) $0.16\ \text{kg} \times 30\ \text{m/s} = 4.8\ \text{kg m/s}$.

Step 2. (b) $\dfrac{4.8\ \text{kg m/s}}{0.04\ \text{s}} = 120\ \text{N}$.

Step 3. (c) $\dfrac{4.8\ \text{kg m/s}}{0.3\ \text{s}} = 16\ \text{N}$.

Step 4. (d) The same momentum is removed over a longer time, so the force is smaller.