题目内容
如图所示,A、B两小球分别连在弹簧两端,B端用细线固定在倾角为30°光滑斜面上,若不计弹簧质量,在线被剪断瞬间,A、B两球的加速度分别为( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604170331957.jpg)
A.都等于
B.
和0
C.
·
和0 D.0和
·![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417158390.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604170331957.jpg)
A.都等于
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417158390.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417158390.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417407710.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417158390.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417407710.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160417158390.png)
D
试题分析:在剪断绳子的一瞬间,弹簧来不及改变,所以弹簧弹力不变,A球合外力仍然为零,加速度为0;剪断绳子前,绳子的拉力为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604180161322.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160418141911.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160418250887.png)
故选D
点评:做本题的关键是知道,绳子间断的瞬间,拉力消失,但是弹簧来不及改变,所以弹力不变,
![](http://thumb2018.1010pic.com/images/loading.gif)
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