题目内容
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082411543306617483.jpg)
(1)要使摩托车运动员从高台水平飞出刚好越过壕沟,求他离开高台时的速度大小;
(2)欲使摩托车运动员能够飞越壕沟,其初速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433082201.gif)
(3)为了保证摩托车运动员的安全,规定飞越壕沟后摩托车着地时的速度不得超过
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433098291.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433113312.gif)
(1)
(2)
(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433160447.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433129459.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433144497.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433160447.gif)
(1)摩托车运动员由高台水平飞出由平抛运动规律;
水平方向
①
竖直方向
②
联立式①②得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433129459.gif)
(2)摩托车运动员由坡底冲上高台,根据动能定理
③
将
代入到式③得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433144497.gif)
(3)从高台水平飞到地面, 由机械能守恒定律
④
解得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433160447.gif)
水平方向
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433207372.gif)
竖直方向
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433222466.gif)
联立式①②得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433129459.gif)
(2)摩托车运动员由坡底冲上高台,根据动能定理
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433285778.gif)
将
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433285454.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433144497.gif)
(3)从高台水平飞到地面, 由机械能守恒定律
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433316718.gif)
解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115433160447.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目