题目内容
如图,细线a和b的一端分别固定在水平地面上,另一端系一个静止在空气中的氢气球,细线与地面的夹角分别为30°和60°。a、b受到拉力分别为Ta和Tb;氢气球受到浮力F,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242334344553170.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242334344553170.jpg)
A.Ta >Tb | B.Ta <Tb |
C.F= Ta | D.F<Tb |
B
试题分析:氢气球受到自身重力,空气浮力和两根细线的拉力作用而处于平衡,受力分析如下图所示
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242334356888076.jpg)
四个力按水平竖直方向正交分解后,在水平方向有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233435703869.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242334371851026.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233438511593.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242334400871037.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233441272642.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233442068872.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233443051497.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233443893495.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824233444876507.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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