18. A 200 g ball is thrown at 30 m/s. It is struck by a bat which gives it a velocity of 40 m/s in the opposite direction. If the time of contact is 10-2s, what is the average force on the ball?
(A)1000 N
(B)1200 N
(C)1400 N
(D)1600 N
(E)None of the above
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統計: 尚無統計資料
統計: 尚無統計資料