题目内容
长度1m的轻绳下端挂着一质量为9.99kg的沙袋,一颗质量为10g的子弹以500m/s的速度水平射入沙袋(未穿出),求在子弹射入沙袋后的瞬间,悬绳的拉力是多大?(设子弹与沙袋的接触时间很短,g取10m/s2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242029373602140.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242029373602140.png)
102.5N
试题分析:子弹射入沙袋的过程,对它们组成的系统,由动量守恒定律
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824202938000789.png)
则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242029388581543.png)
子弹射入沙袋后的瞬间,由牛顿第二定律
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242029401211118.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242029405893131.png)
点评:关键是知道子弹射入沙袋的过程,对它们组成的系统,由动量守恒定律
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目
题目内容