如图所示,质量为m的小球用两条不可伸长的细绳系住,处于静止状

如图所示,质量为m的小球用两条不可伸长的细绳系住,处于静止状态,AB绳水平,OB与竖直方向夹角为θ.在把AB剪断的瞬间,求小球的加速度.

答案

解析:AB绳剪断后,小球在重力及OB绳的拉力作用下,做以O为圆心的圆弧运动.将重力沿半径及切线方向分解,不难求出合力为mgsinθ(沿半径方向合力充当向心力,此时速度为零).

a=gsinθ,方向与OB垂直.

 


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