题目内容
一根轻质细线将2个薄铁垫圈A、B连接起来,一同学用手固定B,此时A、B间距为3L,A距地面为L,如图所示。由静止释放,A、B,不计空气阻力,且A、B落地后均不再弹起。从释放开始到A落地历时t1,A落地前瞬间速率为v1,从A落地到B落在A上历时t2,B落在A上前瞬间速率为v2,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250019472381952.jpg)
A.t1> t2
B.t1= t2
C.v1:v2=1:2
D.v1:v2=1:3
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250019472381952.jpg)
A.t1> t2
B.t1= t2
C.v1:v2=1:2
D.v1:v2=1:3
BC
试题分析:由自由落体运动的规律知,从释放开始到A落地所用时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001947238645.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001947253598.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250019472691159.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001947284901.png)
BC正确,AD错误。
![](http://thumb2018.1010pic.com/images/loading.gif)
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