题目内容
如图所示,用力F拉一物体在水平面上以加速度a运动.用力F′=Fcosθ代替力F,沿水平方向拉物体,该物体的加速度为a′,比较a与a′的大小关系,正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241542220762591.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241542220762591.jpg)
A.a′与a可能相等 | B.a′可能小于a |
C.a′可能大于a | D.a′一定小于a |
AB
试题分析:设为质量为m,与地面间的动摩擦因数为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154222091301.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154222200882.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154222263936.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241542229181184.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154222996951.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154223994389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154224400350.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154224696420.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154224774372.png)
故选AB
点评:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154225024501.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.a′与a可能相等 | B.a′可能小于a |
C.a′可能大于a | D.a′一定小于a |