题目内容
物体A、B的质量之比为mA:mB=4:1,使它们以相同的初速度沿水平地面滑行,若它们受到的阻力相等,那么它们停下来所用的时间之比为tA:tB=______,若两物体与地面的动摩擦因数相同,那么它们停下来所用的时间之比为tA:tB=______
4:1;1:1
(1)假设阻力大小为f,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736143381.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736190380.png)
可得:
因为具有相同的初速度和阻力,所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736221590.png)
(2)假设动摩擦因数大小为
,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736330469.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736190380.png)
可得:
因为具有相同的初速度和动摩擦因数,所以
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736439427.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736143381.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736190380.png)
可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736221406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736221590.png)
(2)假设动摩擦因数大小为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736252251.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736330469.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736190380.png)
可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736408409.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124736439427.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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