题目内容
如图所示,水平U形光滑框架,宽度为1m,电阻忽略不计,导体ab质量是0.2kg,电阻是0.1
,匀强磁场的磁感应强度B=0.1T,方向垂直框架向上,现用1N的外力F由静止拉动ab杆,当ab的速度达到1m/s时,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241512531263774.jpg)
(1)求此时刻ab杆产生的感应电动势的大小;
(2)求此时刻ab杆的加速度的大小;
(3)ab杆所能达到的最大速度是多少。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253064312.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241512531263774.jpg)
(1)求此时刻ab杆产生的感应电动势的大小;
(2)求此时刻ab杆的加速度的大小;
(3)ab杆所能达到的最大速度是多少。
(1)0.1V (2)
(3)10m/s
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253157605.png)
试题分析:(1)当ab的速度达到1m/s时,由法拉第电磁感应定律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253344689.png)
(2)此时安培力为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253407589.png)
由闭合电路欧姆定律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253454519.png)
则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241512535471013.png)
由牛顿第二定律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253610643.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253688633.png)
(3)设ab的最大速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253750365.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253812466.png)
即
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151253937820.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241512540151030.png)
点评:中等难度。本题综合了电磁感应、电路、力学等知识.考查分析和解决综合题的能力。
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目