题目内容
(10分)如图所示,圆心角为90°的光滑圆弧形轨道,半径为1.6m,其底端切线沿水平方向.长为
的斜面,倾角为60°,其顶端与弧形轨道末端相接,斜面正中间有一竖直放置的直杆,现让质量为1Kg的物块从弧形轨道的顶端由静止开始滑下,物块离开弧形轨道后刚好能从直杆的顶端通过,重力加速度取10m/s2,求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250031583953725.jpg)
(1)物块滑到弧形轨道底端时对轨道的压力大小;
(2)直杆的长度为多大.
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003158364633.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250031583953725.jpg)
(1)物块滑到弧形轨道底端时对轨道的压力大小;
(2)直杆的长度为多大.
(1)30N;(2)2.1m;
试题分析:(1)沿弧形轨道下滑过程:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003158411782.png)
在轨道最低点时:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003158427890.png)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250031584421148.png)
由牛顿第三定律可知物块对轨道的压力大小为30N (1分)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003158473811.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825003158489646.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250031585051031.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目