题目内容
(15分)如图所示,一细线的一端固定于倾角为
的光滑楔形滑块A上的顶端O处,细线另一端栓一质量为
的小球,取
.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023235322489.png)
(1)当滑块静止时,线中拉力
等于多少?
(2)当滑块从静止向左加速运动时,小球恰好对斜面无压力,经过2秒钟小球运动的位移是多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323470381.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323485619.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323501664.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023235322489.png)
(1)当滑块静止时,线中拉力
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323548304.png)
(2)当滑块从静止向左加速运动时,小球恰好对斜面无压力,经过2秒钟小球运动的位移是多少?
(1)
(2) ![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323579537.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323563718.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323579537.png)
试题分析:(1)对小球受力分析如图,小球处于平衡状态有
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323594486.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250023236104927.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323626844.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323641748.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323563718.png)
(2)小球和滑块一起向左加速,小球恰好对斜面无压力,对小球受力分析如图,由牛顿第二定律有:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323688748.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323704754.png)
可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323719387.png)
由运动学公式可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002323735821.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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