题目内容
(10分)如图所示,质量为m,电荷量为e的粒子从A点以v0的速度沿垂直电场线方向的直线AO方向射入匀强电场,由B点飞出电场时速度方向与AO方向成
=45°,已知AO的水平距离为d。(不计重力)求:(1)从A点到B点用的时间;(2)匀强电场的电场强度大小;(3)AB两点间电势差
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241516097645354.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609655299.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241516097645354.png)
(1)
(2)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609967891.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609827524.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609874808.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609967891.png)
试题分析:(1) 根据类平抛运动的规律,水平方向为匀速直线运动:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151610061515.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609827524.png)
(2)由B点速度合成图可知:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151610357454.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151610466829.png)
∴
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151610576886.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609874808.png)
(3)由A到B过程中由动能定理可知:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241516108101028.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151609967891.png)
点评:此类题型考察了类平抛运动规律、动能定理在电场类问题中的运用
![](http://thumb2018.1010pic.com/images/loading.gif)
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