問題詳情
14. A 30-kg block is on a horizontal surface. The block is at rest when, at t = 0, a force (magnitude P =12 N) acting parallel to the surface is applied to the block causing it to accelerate. The coeflicient ofkinetic friction between the block and the surface is 0.20. At what rate is the force P doing work onthe block at t = 2.0 s? Take g = 10 m/s?.
(A)54W
(B)48W
(C)42W
(D)59 W
(E) 24 W
參考答案
答案：B
難度：計算中-1
書單：沒有書單，新增