题目内容
某同学利用如图所示的装置验证动量守恒定律。图中两摆摆长相同,悬挂于同一高度,A、B两摆球均很小,质量之比为1:2。当两摆均处于自由静止状态时,其侧面刚好接触。向右上方拉动B球使其摆线伸直并与竖直方向成45°角,然后将其由静止释放。结果观察到两摆球粘在一起摆动,且最大摆角成30°。若本实验允许的最大误差为±4%,此实验是否成功地验证了动量守恒定律?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250004590502068.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250004590502068.jpg)
此实验在规定的范围内验证了动量守恒定律
试题分析:设摆球A、B的质量分别为mA、mB,摆长为l,B球的初始高度为h1,碰撞前B球的速度为vB.在不考虑摆线质量的情况下,根据题意及机械能守恒定律得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000459066821.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000459081882.png)
设碰撞前后两摆球的总动量大小分别为P1、P2,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000459097581.png)
联立①②③式可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250004591901103.png)
同理可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250004592221265.png)
联立④⑤可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250004592531365.png)
代入已知条件得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000459268934.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000459300799.png)
所以,此实验在规定的范围内验证了动量守恒定律。
![](http://thumb2018.1010pic.com/images/loading.gif)
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