题目内容
如图所示,在光滑水平面上有物体A、B,质量分别为
、
。在拉力F作用下,A和B以加速度
做匀加速直线运动。某时刻突然撤去拉力F,此瞬时A和B的加速度为a1和a2则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241535476293742.jpg)
A.
B.
;
C.
;
D.
;![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548206659.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547286361.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547348389.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547488283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241535476293742.jpg)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547644494.png)
B.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547722367.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547832424.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547988720.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548081744.png)
D.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547722367.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548206659.png)
D
试题分析:当突然撤去拉力F,此瞬时弹簧的弹力与F撤去前相同,即A物体所受的力不变,其加速度不变得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153547722367.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548674441.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548877596.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153548206659.png)
点评:学生明确因弹簧的形变量较大,知弹簧的弹力不能突变,即在外力改变的一瞬间弹簧的弹力与外力改变前相同。
![](http://thumb2018.1010pic.com/images/loading.gif)
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