题目内容
一质量为
的物体P静止于光滑水平地面上,其截面如图所示。图中
为粗糙的水平面,长度为L;
为一光滑斜面,斜面和水平面通过与
和
均相切的长度可忽略的光滑圆弧连接。现有一质量为
的木块以大小为
的水平初速度从
点向左运动,在斜面上上升的最大高度为
,返回后在到达
点前与物体P相对静止。重力加速度为g。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609230284413.jpg)
求(1)木块在
段受到的摩擦力
;
(2)木块最后距
点的距离
。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160920750419.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160921374374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160921530335.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160921374374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160921530335.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922185338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922419325.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922622283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922731313.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922622283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609230284413.jpg)
求(1)木块在
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160921374374.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160923184316.png)
(2)木块最后距
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160922622283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160923574259.png)
(1)
(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160923839977.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609236981008.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160923839977.png)
试题分析:(1)设木块和物体P共同速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160924400266.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160924525716.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609247591312.png)
由①②得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609236981008.png)
(2)木块返回与物体P第二次达到共同速度与第一次相同(动量守恒)全过程能量守恒得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241609251181275.png)
由②③④得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160923839977.png)
点评:关键是正确写出动量守恒和能量守恒的方程.是一道中档次题.
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目