题目内容
如图所示,三根轻细绳悬挂两个质量相同的小球保持静止,A、D间细绳是水平的,现对B球施加一个水平向右的力F,将B缓缓拉到图中虚线位置,这时三根细绳张力
的变化情况是
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500012473713355.png)
A. 都变大
B.
和
变大,
不变
C.
和
变大,
不变
D.
和
变大,
不变
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124706572.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500012473713355.png)
A. 都变大
B.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124862384.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124877396.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000125096398.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000125096398.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124877396.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124862384.png)
D.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000125096398.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124862384.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000124877396.png)
B
试题分析:先以小球B为研究对象,在力F的作用下,由原来的二力平衡变成三力平衡问题,很明显绳子AB上的弹力增大;再以小球A、B的整体为研究对象,整体受力如下图所示,根据正交分解法,F的出现,使得绳子AD上的弹力增大,但不影响AC上的弹力,选项B正确,其余均错误。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001256261253.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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