本题目来源于试卷: Work Energy and Power，类别为 美国物理杯赛(Physics Bowl)
[单选题]
94.38: A force F at an anglxnn)kv9v3nzv.e r)3*bc7,xbqc 5o;l z y6aoze θ above the horizont 7a,fpy1g+ y;qcnnfryjqcm* q7a3 6 +tal is used to pull a heavy suitcase of weight mgc76nf*n1 ta,yqryfy+ pqmc g7 3a;q j+a distance d along a level floor at constant velocity. The coefficient of friction between the floor and the suitcase is μ. The work done by the frictional force is:
A. $–Fd cosθ$
B. $mgh – Fd cosθ$
C. $–Fμdcosθ $
D. $–mgμd$
E. $ –mgμdcosθ$
参考答案: A
本题详细解析:
暂无
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