题目内容
如图所示,电梯质量为M,它的水平地板上放置一质量为m的物体,电梯在钢索的拉力作用下由静止开始竖直向上加速运动,当上升高度为H时,电梯的速度达到v,则在这个过程中
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242312523681588.jpg)
A.电梯地板对物体的支持力做的功等于![]() |
B.电梯地板对物体的支持力所做的功等于![]() |
C.钢索的拉力所做的功等于![]() |
D.钢索的拉力所做的功大于![]() |
BD
试题分析:对物体根据动能定理
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824231258857950.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824231253241586.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824231253241586.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242313027891299.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824231253241586.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目