题目内容
如图1—6所示,重球用绳子挂在光滑的墙上,当保持球的重力不变而增大球的半径时,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241232497803563.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241232497803563.png)
A.绳的张力不变,墙的压力不变 |
B.绳的张力增大,墙的压力增大 |
C.绳的张力减小,墙的压力减小 |
D.绳的张力减小,墙的压力增大 |
B
本题考查物体的平衡。对球受力分析,受重力
、绳的拉力
和墙壁的弹力
,设绳与墙壁夹角为
,则
,当球半径增大时,
增大,绳的拉力
增大,墙壁的弹力
增大,选B。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249874316.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249905304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249921357.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249952297.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241232499681041.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249952297.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249905304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824123249921357.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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