题目内容
如图所示,一个质量为
的物体以某一速度从A点冲上倾角为30°的斜面,其运动的加速度为
,这物体在斜面上上升的最大高度为h,则物体在此过程中
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001019922947.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000101945337.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000101961477.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001019922947.png)
A.重力势能增加了![]() |
B.动能损失了![]() |
C.机械能损失了![]() |
D.物体克服摩擦力的功率随时间在均匀减小 |
D
试题分析:物体上升高度h过程中,重力做功-mgh,重力势能增加mgh,答案A错,根据倾角30度,可知物体沿斜面上升位移为2h,此过程合力为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000102054692.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001020861146.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000102101673.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250001021321064.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000102335646.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000102632931.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目