[问答题]
A squash ball hits a wa3kyo7- fzv, dqlb)u 6cl roi7iv4i0o r:l at a 45 $^{\circ} $ angle as shown in Fig. 7–30. What is the direction (a) of the change in momentum of the ball, (b) of the force on the wall?
参考答案:
(a)The downward component of the momentum is unchanged. The horizontal component of
momentum changes from rightward to leftward. Thus the change in momentum is to the left in the picture.
(b)Since the force on the wall is opposite that on the ball, the force on the wall is to the right.
