题目内容
如图所示,两根电阻不计、相距L且足够长的平行光滑导轨与水平面成
角,导轨处在磁感应强度B的匀强磁场中,磁场方向垂直导轨平面斜向上,导轨下端连接阻值为R的电阻。现让一质量为m,电阻也为R、与导轨接触良好的水平金属棒ab从静止开始下滑,ab下滑距离s后开始匀速运动,重力加速度为g。求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053278207.png)
(1)ab棒匀速下滑时速度v的大小;
(2)ab棒从静止至开始匀速下滑的过程中,ab棒上产生的热量。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005005296297.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053278207.png)
(1)ab棒匀速下滑时速度v的大小;
(2)ab棒从静止至开始匀速下滑的过程中,ab棒上产生的热量。
(1)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053741459.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053581043.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053741459.png)
试题分析:(1)ab棒匀速下滑时
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005005390767.png)
ab棒匀速下滑时切割磁感线产生感应电动势
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005005405530.png)
由欧姆定律可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005005436592.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825005005452586.png)
联立可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053581043.png)
(2)ab棒与电阻R串联,电流相等,产生的热量Q相同(2分)
由能量守恒得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050054991101.png)
可得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250050053741459.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目