一质量为m的物体,置于水平长木板上,物体与木板间的动摩擦因数

一质量为m的物体,置于水平长木板上,物体与木板间的动摩擦因数为μ.现将长木板的一端缓慢抬起,要使物体始终保持静止,木板与水平地面间的夹角θ不能超过多少?设最大静摩擦力等于滑动摩擦力

答案


见解析
【试题分析】
这是一个斜面问题.当θ增大时,重力沿斜面的分力增大.当此分力增大到等于最大静摩擦力时,物体处于动与不动的临界状态.此时θ最大.依题意
mgsinθ=μmgcosθ
tanθ=μ     
所以 θ≤arctanμ

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