题目内容
半径为R的光滑圆弧形轨道中心O和最低点C附近各有一金属小球A和B,如图所示,同时释放小球A、B,两球到达最低点C的先后顺序是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241205511682211.jpg)
A.A比B先到达 B.B比A先到达
C.A、B同时到达 D.不能确定谁先到达
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241205511682211.jpg)
A.A比B先到达 B.B比A先到达
C.A、B同时到达 D.不能确定谁先到达
A
小球A做自由落体运动,设下落到C点的时间为tA,则tA=
;小球B的运动为等效单摆运动,设B运动到C点所用的时间为tB,则tB=
=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120551231230.gif)
,有tA<tB,A先于B到达C点,故A项正确.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120551200336.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120551215231.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120551231230.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120551246306.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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