题目内容
(1)在光电效应试验中,某金属的截止频率相应的波长为
,该金属的逸出功为______。若用波长为
(
<
)单色光做实验,则其遏止电压为______。已知电子的电荷量,真空中的光速和布朗克常量分别为e,c和h。
(2)如图,ABC三个木块的质量均为m。置于光滑的水平面上,BC之间有一轻质弹簧,弹簧的两端与木块接触可不固连,将弹簧压紧到不能再压缩时用细线把BC紧连,是弹簧不能伸展,以至于BC可视为一个整体,现A以初速![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215515193.gif)
沿BC的连线方向朝B运动,与B相碰并粘合在一起,以后细线突然断开,弹簧伸展,从而使C与A,B分离,已知C离开弹簧后的速度恰为
。求弹簧释放的势能。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241242155628363.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215157197.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215157197.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215157197.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215500216.gif)
(2)如图,ABC三个木块的质量均为m。置于光滑的水平面上,BC之间有一轻质弹簧,弹簧的两端与木块接触可不固连,将弹簧压紧到不能再压缩时用细线把BC紧连,是弹簧不能伸展,以至于BC可视为一个整体,现A以初速
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215515193.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215531127.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124215547204.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241242155628363.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082412421557817377.jpg)
略
![](http://thumb2018.1010pic.com/images/loading.gif)
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