题目内容
质量m=60kg的消防队员,从一根竖直的长直杆上由静止滑下,经t=2.0s着地。消防队员整个下滑过程的v-t图象如图所示。求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500270829711178.png)
(1)消防队员着地时的速度大小v2;
(2)消防队员第1s内的加速度大小a1;
(3)消防队员沿杆下滑的距离h。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/2014082500270829711178.png)
(1)消防队员着地时的速度大小v2;
(2)消防队员第1s内的加速度大小a1;
(3)消防队员沿杆下滑的距离h。
(1)
(2)
(3)3.5m
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708313550.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708328624.png)
试题分析:解:设加速运动时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708344291.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708360345.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708375327.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708406361.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708422298.png)
(1)由图可知:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708313550.png)
(2)根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708453597.png)
代入数据得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708328624.png)
(3)由公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708500696.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708516783.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708531650.png)
代入数据得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002708562762.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目