题目内容
A、B两物体在光滑的水平面上相向运动,其中物体A的质量为mA=4 kg,两球发生相互作用前后的运动情况如图14-1-5所示,则:
(1)由图可知A、B两物体在________时刻发生碰撞,B物体的质量为mB=________kg.
(2)碰撞过程中,系统的机械能损失多少?![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241413141684168.jpg)
(1)由图可知A、B两物体在________时刻发生碰撞,B物体的质量为mB=________kg.
(2)碰撞过程中,系统的机械能损失多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241413141684168.jpg)
(1)2 s 6 (2)30 J
(1)由图可知物体A、B在2 s时发生碰撞.取物体B运动的方向为正方向,由动量守恒定律和图象得
mAvA+mBvB=(mA+mB)v
mB=
=
kg=6 kg.
(2)ΔEk=
mAvA2+
mBvB2-
(mA+mB)v2
=
×4×22 J+
×6×32 J-
×(4+6)×12 J
=30 J
mAvA+mBvB=(mA+mB)v
mB=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314183705.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314261698.png)
(2)ΔEk=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141314308338.png)
=30 J
![](http://thumb2018.1010pic.com/images/loading.gif)
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