题目内容
火车进站时的初速度为54
,2s后匀减速到36
.
试求:(1)火车进站时的加速度
(2)火车进站经过10S通过的位移
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634357388.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634357388.gif)
试求:(1)火车进站时的加速度
(2)火车进站经过10S通过的位移
(1)-2.5m/s2 (2)45m
(1)设火车进站时做匀减速直线运动的加速度为a,则根据
有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634419685.gif)
(2)设火车经过
的时间速度减少到零,同样根据![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634388419.gif)
有![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634466689.gif)
火车进站在10S内通过的位移与在6S通过的位移相等,
即![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634497645.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634513755.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634388419.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634419685.gif)
(2)设火车经过
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634435205.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634388419.gif)
有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634466689.gif)
火车进站在10S内通过的位移与在6S通过的位移相等,
即
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634497645.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824115634513755.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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