题目内容
如图所示,卷扬机的细绳通过光滑的定滑轮用恒力F拉放在倾角为30°粗糙斜面上的木箱,使之以
的加速度沿斜面匀加速向上移动x,已知木箱的质量为m,拉力F=mg。则在此过程中,下列说法中正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242300498537529.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824230049057374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242300498537529.png)
A.木箱受到的摩擦力为![]() |
B.重力势能增加了![]() |
C.动能增加了![]() |
D.多消耗的电能为![]() |
ABC
试题分析: 根据牛顿运动定律:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824230053846834.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824230054735648.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242300556401028.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824230051615579.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242300584011036.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824230059696760.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.木箱受到的摩擦力为![]() |
B.重力势能增加了![]() |
C.动能增加了![]() |
D.多消耗的电能为![]() |