题目内容
用如图所示装置来验证动量守恒定律,质量为
的钢球B放在小支柱N上,球心离地面高度为H;质量为
的钢球A用细线拴好悬挂于O点,当细线被拉直时O点到球心的距离为L,且细线与竖直线之间夹角
;球A由静止释放,摆到最低点时恰与球B发生正碰,碰撞后,A球把轻质指示针C推移到与竖直夹角为
处,B球落到地面上,地面上铺有一张盖有复写纸的白纸D,用来记录球B的落点.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241345571634793.jpg)
(1)用图中所示各个物理量的符号表示碰撞前后两球A、B的动量(设两球A、B碰前的动量分别为
、
;碰后动量分别为
、
),则
= ;
= ;
= ; = 。
(2)请你提供两条提高实验精度的建议: 、 。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134556992389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557038399.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557070310.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557101339.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241345571634793.jpg)
(1)用图中所示各个物理量的符号表示碰撞前后两球A、B的动量(设两球A、B碰前的动量分别为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557179372.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557241365.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557288422.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557350410.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557179372.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557288422.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557241365.png)
(2)请你提供两条提高实验精度的建议: 、 。
(1)
;
;0;
;(每空1分)
(2)①让球A多次从同一位置摆下,求B球落点的平均位置;②
角取值不要太小;③两球A、B质量不要太小;④球A质量要尽量比球B质量大。(答对任意其中两个都得2分)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557631942.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557678976.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557740832.png)
(2)①让球A多次从同一位置摆下,求B球落点的平均位置;②
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557070310.png)
(1)碰撞前A球的动量:
①
②
③由三式得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558037397.png)
。碰撞前B球的静止,故动量为零。碰撞后A球的动量为:
④
⑤
=
⑥由三式得
=
。碰撞后B球的动量为:
⑦
⑧
=
⑨由三式得
=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557740832.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557865884.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557912724.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557974600.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558037397.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557631942.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558146906.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558162773.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557288422.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558240498.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557288422.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557678976.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558411639.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558458528.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557350410.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134558552477.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557350410.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824134557740832.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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