题目内容
如图所示,一个点光源S放在平面镜MN前,若MN保持不动,光源S以速率v=2m/s沿与平面镜成
角的方向向右匀速运动,试求光源在平面镜中的像的运动情况.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241201491341254.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149118965.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241201491341254.gif)
点光源在平面镜中所成的像的速度大小等于v,方向与平面镜成
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149118965.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241201492901473.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241201493051587.gif)
[方法一]如图所示设点光源经t时间由S处运动到
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149337948.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149368941.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149383952.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149399972.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149415985.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149430949.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149118965.gif)
[方法二]如图所示,将点光源的速度分解成垂直于平面方向的速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149461947.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149477943.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149368941.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149368941.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149539948.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149539953.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149727933.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149118965.gif)
补充
当点光源S与平面镜的相对位置发生变化时,点光源在平面镜中所成的像与平面镜的相对位置亦发生变化.求解光源的像的运动,即是求解像点相对于平面镜的位置关系如何变化.
[思路一]利用平面镜成像的对称性,可作出任意两时刻的光源的位置及像点的位置,求解出像点的位移随时间的变化规律即可求出像的运动情况.
[思路二]若将光源的速度分解成平行于镜面方向的速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149758943.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149773943.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149758943.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120149773943.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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