题目内容
如图16-4-13所示,质量均为m的A、B两个弹性小球,用长为2l的不可伸长的轻绳连接,现把A、B两球置于距地面高H处(H足够大),间距为l,当A球自由下落的同时,将B球以速度v0指向A球水平抛出.求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208259991570.jpg)
图16-4-13
(1)两球从开始运动到相碰,A球下落的高度;
(2)A、B两球碰撞(碰撞时无机械能损失)后,各自速度的水平分量;
(3)轻绳拉直过程中,B球受到绳子拉力的冲量大小.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241208259991570.jpg)
图16-4-13
(1)两球从开始运动到相碰,A球下落的高度;
(2)A、B两球碰撞(碰撞时无机械能损失)后,各自速度的水平分量;
(3)轻绳拉直过程中,B球受到绳子拉力的冲量大小.
(1) h=
.③
(2)
=v0,
=0.
(3) m
.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826030437.gif)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826045227.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826061227.gif)
(3) m
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108241.gif)
(1)设A球下落的高度为h,
l=v0t,①
h=
gt2②
联立①②得h=
.③
(2)由水平方向动量守恒得
mv0=mvAx′+mvBx′④
由机械能守恒得
m(v02+
)+
m
=
m(vA′2+
)+
m(
+
) ⑤
式中
,
.
联立④⑤得
=v0,
=0.
(3)由水平方向动量守恒得mv0=2mvBx″,
l=mvBx″=m
.
l=v0t,①
h=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108225.gif)
联立①②得h=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826030437.gif)
(2)由水平方向动量守恒得
mv0=mvAx′+mvBx′④
由机械能守恒得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826342337.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826560337.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826591337.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108225.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826623345.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826638339.gif)
式中
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826654403.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826669403.gif)
联立④⑤得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826045227.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826061227.gif)
(3)由水平方向动量守恒得mv0=2mvBx″,
l=mvBx″=m
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120826108241.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目