如图所示,重球m用一条不可伸长的轻质细线拴住后悬于O点,重球置

如图所示,重球m用一条不可伸长的轻质细线拴住后悬于O点,重球置于一个斜劈M上,用水平力F向左推动斜劈M在光滑水平桌面上由位置甲匀速向左移动位置乙,在此过程中,正确的说法是        (    )

A.M.m间的弹力对m不做功

B.M.m间的摩擦力对m做负功

C.细线的拉力对小球不做功

D.重力对小球做负功

 

答案

CD

解析:略

 

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