题目内容
在“探究求合力的方法”实验中,如图所示,用AB两弹簧秤拉橡皮条结点O,使其位于E处,此时
+
=90°,然后保持A的读数不变,当
角由图中所示的值逐渐减小时,要使结点仍在E处,可采取的办法是 。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241433153074798.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143314980280.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143315042308.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143314980280.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241433153074798.png)
A.增大B的读数,减小![]() |
B.减小B的读数,减小![]() |
C.减小B的读数,增大![]() |
D.增大B的读数,增大![]() |
B
当合力不变,夹角减小时,由平行四边形可知要减小分力大小,同时为了保证合力方向不变,水平方向分力平衡,所以要减小
角
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824143315042308.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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