题目内容
如图所示,一滑雪运动员质量m=60kg,经过一段加速滑行后从A点以vA=10m/s的初速度水平飞出,恰能落到B点.在B点速度方向(速度大小不变)发生改变后进入半径R=20m的竖直圆弧轨道BO,并沿轨道下滑.已知在最低点O时运动员对轨道的压力为2400N.A与B、B与O的高度差分别为H=20m、h=8m.不计空气阻力,取g=10m/s2,求:
(1)AB间的水平距离.
(2)运动员在BO段运动时克服阻力做的功.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244031714290.jpg)
(1)AB间的水平距离.
(2)运动员在BO段运动时克服阻力做的功.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241244031714290.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082412440320223154.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403218939.gif)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403234499.gif)
或:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403577547.gif)
故
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403592742.gif)
设由B到O克服摩擦力做功为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403608347.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403624813.gif)
解得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824124403234499.gif)
略
![](http://thumb2018.1010pic.com/images/loading.gif)
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