题目内容
.在竖直墙壁和水平地面间,建立如图所示的BM、AM、AN三个光滑斜面,BM与地面间的夹角为45°,AM与地面间的夹角为60°,AN与地面间的夹角为30°。一质点分别从BM、AM、AN这三个斜面的最高由静止开始释放,沿斜面滑到最低点时间分别为t1、t2、t3,则( ).
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250020262854883.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250020262854883.jpg)
A.t1<t2<t3 | B.t1=t2=t3 |
C.t1=t2<t3 | D.t1<t2=t3 |
A
试题分析:对AN、AM两个斜面来讲,斜面的高度相等设为h,物体在斜面上加速下滑,有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002026300919.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002026316840.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002026331980.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002026347926.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目