题目内容
如图所示,物体甲从高H处以速度v1平抛,同时物体乙从距甲水平方向距离x处由地面以速度v2竖直上抛,不计空气阻力,两个物体在空中某处相遇,下列叙述中正确的是 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324383671471.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324383671471.png)
A.从抛出到相遇所用的时间是x/v1 |
B.如果相遇发生在乙上升的过程中,则v2> |
C.如果相遇发生在乙下降的过程中,则v2< |
D.若相遇点离地面高度为H/2,则v2= |
ABD
两物体只可能在乙的竖直方向上相遇,所以甲水平位移为x,甲水平方向做匀速直线运动,所用时间
。甲下落位移为
如果相遇发生在乙上升过程中,
,
下落时间小于
,所以
.如果相遇发生在乙下降过程中,
,下落时间小于
,所以
.当相遇点离地面高度为H/2时
,所以
。所以选ABD。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438398502.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324384291011.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324384601107.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438507938.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438538557.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438585585.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241324384601107.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438538557.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438725686.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438757679.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132438819556.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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