问题 不定项选择

如图所示,质量为M、长度为L的木板静止在光滑的水平面上,质量为m的小物体(可视为质点)放在木板上最左端,现用一水平恒力F作用在小物体上,使物体从静止开始做匀加速直线运动。已知物体和木板之间的摩擦力为Ff当物体滑到木板的最右端时,木板运动的距离为x,则在此过程中

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A.物体到达木板最右端时具有的动能为(FFf)(Lx)

B.物体到达木板最右端时,木板具有的动能为Ffx

C.物体克服摩擦力所做的功为FfL

D.物体和木板增加的机械能为Fx

答案

答案:B

问答题
填空题

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