Question

8.34

A catcher catches a 145 g baseball traveling horizontally at 30.0 m/s .

A. How large an impulse does the ball give to the catcher?

ANSWER: p= ___________ Kg*m/s

B. If it takes the ball 25.0 ms to stop once it is in contact with the catcher's glove, what average force did the ball exert on the catcher?

ANSWER: F= __________ N

Answer 1

A.

$p=mv=(0.145kg)*(30m/s)=4.35kg.m/s$

B.

$F_{prom}=\left | \frac{\Delta p}{\Delta t} \right |=\left | \frac{0-4.35kg.m/s}{25*10^{-3}s} \right |=174N$

Now consider that Force as impulse are vectors, but here we are working only with the magnitudes of the vector, then the magnitude of force will be positive even though $\Delta p$ is negative.

Good luck!