题目内容
如图所示,AO、BO、CO是完全相同的三条绳子,将一根均匀的钢梁吊起。当钢梁足够重时,结果AO先断,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250033554271600.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250033554271600.jpg)
A.α>120° | B.α<120° |
C.α=120° | D.无法确定 |
B
OA绳拉力FA的两个分力沿OB、OC绳向上,大小等于OB、OC绳的拉力FB、FC,如图所示。若OA先断则说明FA>FB(FB=FC),故α<120°,B正确。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250033554422676.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250033554422676.jpg)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.α>120° | B.α<120° |
C.α=120° | D.无法确定 |