## Physics: Principles with Applications (7th Edition)

a. 1.7$\frac{kg \cdot m}{s}$ b. 490N
a. To find the impulse, calculate the change in momentum. Let the positive direction be the direction of the ball’s motion. $$\Delta p = m \Delta v = (4.5 \times 10^{-2} kg)(38 \frac{m}{s}-0) \approx 1.7 \frac{kg \cdot m}{s}$$ b. Find the average force by dividing the impulse by the time the objects are in contact. $$F_{av}=\frac{\Delta p}{\Delta t}=\frac{1.71 kg \cdot m/s}{3.5 \times 10^{-3} s}=490 N$$