题目内容
在竖直平面内,一根光滑金属杆弯成如图所示形状,相应的曲线方程为y=2.5 cos
(单位:m),式中k=1m-1。将一光滑小环套在该金属杆上,并从x=0处以v0=5m/s的初速度沿杆向下运动,取重力加速度g=10m/s2。则当小环运动到x=
m时的速度大小v=__________m/s;该小环在x轴方向最远能运动到x=__________m处。![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241950561233127.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195054048881.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195055125413.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241950561233127.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195057309412.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195058151482.png)
试题分析:光滑小环在沿金属杆运动的过程中,只有重力做功,机械能守恒,由曲线方程可知,环在x=0处的y坐标是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195059118611.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195100335524.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241951009431413.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241951018011289.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195102675671.png)
当环运动到最高点时,速度为零,同理有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241951033151213.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195104297826.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824195105155685.png)
点评:本题难度较大,换在运动过程中,机械能守恒,根据曲线方程可以确定环的位置
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目