题目内容
2013年8月24日北京夜光风筝比赛现场,某段时间内某小赛手和风筝均保持静止状态,此时风筝平面与水平面夹角为30°,风筝的质量为m=1kg,轻质细线中的张力为FT=10N,该同学的质量为M=29kg,则以下说法正确的是(风对风筝的作用力认为与风筝垂直,g取10m/s2)( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250003545442084.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250003545442084.jpg)
A.风对风筝的作用力为10![]() |
B.细线与水平面的夹角为30° |
C.人对地面的摩擦力方向水平向左 |
D.人对地面的压力大小等于人和风筝整体的重力,即300 N |
AB
试题分析:对风筝进行受力分析如图所示
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250003545753437.jpg)
将所有的力沿风筝和垂直于风筝进行正交分解,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354591869.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354606967.png)
可得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354638502.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354653657.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354669403.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825000354684398.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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