题目内容
“儿童蹦极”中,拴在腰间左右两侧的是弹性极好的橡皮绳。质量为m的小明如图所示静止悬挂时,两橡皮绳的拉力大小均恰为mg,若此时小明左侧橡皮绳在腰间断裂,则小明此时
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030331883083.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030331883083.jpg)
A.加速度为零,速度为零 |
B.加速度a=g,沿原断裂橡皮绳的方向斜向下 |
C.加速度a=g,沿未断裂橡皮绳的方向斜向上 |
D.加速度a=g,方向竖直向下 |
B
试题分析:小明静止时受到重力和两根橡皮条的拉力,处于平衡状态,如图所示:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500303320418864.png)
由于
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003033219637.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003033235414.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003033250273.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目