题目内容
如图所示,一电子沿Ox轴射入电场,在电场中的运动轨迹为OCD,已知
,电子过C、D两点时竖直方向的分速度为vCy和vDy;电子在OC段和OD动能变化量分别为△EK1和△EK2,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050263925864.jpg)
A.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205027047652.png)
B.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205028014635.png)
C.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205028716784.png)
D.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205029247748.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205025284529.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050263925864.jpg)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205027047652.png)
B.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205028014635.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205028716784.png)
D.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205029247748.png)
AD
试题分析:电子沿Ox轴射入匀强电场,做类平抛运动,水平方向做匀速直线运动,已知
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205029808521.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205030542915.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205031524895.png)
根据匀变速直线运动的推论可知,在竖直方向上:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205032741658.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205033833989.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205034660746.png)
故选AD
点评:本题是类平抛运动问题,运用运动的分解法研究,灵活运用比例法求解,比较简单.
![](http://thumb2018.1010pic.com/images/loading.gif)
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