试题与答案

如图所示,一根跨越一固定水平光滑细杆的轻绳两端拴有两个质量均为m的小球a和b(可

题型:计算题

题目:

如图所示,一根跨越一固定水平光滑细杆的轻绳两端拴有两个质量均为m的小球a和b(可视为质点), Oa段的长度为L1,Ob段的长度为L2,且L1>L2,球a置于地面,球b被拉到与细杆同一水平的位置,在绳刚拉直时放手,小球b从静止状态向下摆动,当球b摆到最低点时,恰好与球a在同一水平位置发生碰撞并粘合在一起,设碰撞时间极短,往后两球以O点为圆心做圆周运动,若已知碰前瞬间球a的速度大小为va,方向竖直向上,轻绳不可伸长且始终处于绷紧状态,(已知a,b质量相同)求:

(1)球b在碰撞前瞬间的速度大小;

(2)两小球粘合后将做圆周运动时绳中张力的大小。

答案:

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参考答案:D

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