题目内容
(9分)如图所示,在光滑的水平面上,质量为4m、长为L的木板右端紧靠竖直墙壁,与墙壁不粘连。质量为m的小滑块(可视为质点)以水平速度v0滑上木板左端,滑到木板右端时速度恰好为零。现小滑块以水平速度:滑上木板左端,滑到木板右端时与竖直墙壁发生弹性碰撞,以原速率弹回,刚好能够滑到木板左端而不从木板上落下,求
的值。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250040110915795.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011044381.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250040110915795.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011107558.png)
试题分析:小滑块以水平速度v0右滑时,有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011122830.png)
小滑块以速度v滑上木板到运动至碰墙时速度为v1,则有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011138858.png)
滑块与墙碰后至向左运动到木板左端,此时滑块、木板的共同速度为v2,
则有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011153747.png)
由总能量守恒可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250040111691101.png)
上述四式联立,解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004011107558.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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