题目内容
(15分) 薄木板长L=1m,质量M=9kg在动摩擦因数μ1=0.1的水平地面上向右滑行,当木板速度v0=2m/s时,在木板的右端轻放一质量m=1kg的小铁块(可视为质点)如图所示,当小铁块刚好滑到木板左端时,铁块和木板达到共同速度。取g=10m/s2,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030540922549.jpg)
(1)从铁块放到木板上到它们达到相同速度所用的时间t;
(2)小铁块与木板间的动摩擦因数μ2 。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030540922549.jpg)
(1)从铁块放到木板上到它们达到相同速度所用的时间t;
(2)小铁块与木板间的动摩擦因数μ2 。
(1)t=1s (2)![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054108557.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054108557.png)
试题分析:(1)设木板在时间t内的位移为x1;铁块的加速度大小为a2,时间t内的位移为x2
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030541233080.jpg)
则有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054139786.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054154678.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054170511.png)
又
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054186591.png)
(2)根据牛顿第二定律,有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250030542011118.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054217667.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003054108557.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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