题目内容
某物体以初速度20m/s水平抛出后,2s末的速度大小是 ,方向与水平方向的夹角为 ,它的加速度为 。(取g=10m/s2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121158939606.png)
本题考查速度的合成
物体以初速度
20m/s水平抛出后,忽略空气阻力,在水平方向上作匀速直线运动,在竖直方向上作初速度
为的匀加速运动,2s末在竖直方向上的速度为
;2s末的合速度
是
与
的矢量和,则速度大小为
;
由
及
知,由
、
及
构成的三角形为等腰直角三角形,则
与
成
角,即2s末速度的方向与水平方向成
角;
整个运动过程中物体只受重力作用,其加速度为![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159750632.png)
物体以初速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121158986599.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159033402.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159079662.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159111252.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159142304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159189280.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159235941.png)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159298592.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121158986599.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159142304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159189280.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159111252.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159111252.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159142304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159516339.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159516339.png)
整个运动过程中物体只受重力作用,其加速度为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824121159750632.png)
![]() |
![](http://thumb2018.1010pic.com/images/loading.gif)
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