题目内容
如图所示,质量分别为m和2m的A、B两物块用轻弹簧相连,放在光滑水平面上,A靠紧竖直墙。现用力F向左缓慢退物块B压缩弹簧,当力F做功为W时,突然撤去F,在A物体开始运动以后,弹簧弹性势能的最大值是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241541075075530.jpg)
A.
B.
C.
D.W
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241541075075530.jpg)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154107523371.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154107695373.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154107773394.png)
A
试题分析:撤去F,在A物体开始运动以后,A在加速,B在减速,A、B间的距离在增大,当A、B间距离最大时,二者速度相等,此时弹簧有最大弹性势能。撤去F,系统机械能守恒,由题意可知,系统总的机械能为W。在A开始离开墙壁时,弹簧处于原长,此时B物体的动能为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154107835570.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241541080071003.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154108443539.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154108677840.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241541087711113.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824154108833911.png)
故选A
点评:本题要注意哪个阶段开始机械能守恒,哪个阶段开始动量守恒,并且要知道机械能在各个时刻存在的形式。
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目