题目内容
(10分)如图所示,悬挂的直杆AB长1m,在B以下0.2m处,有一长0.6m的无底圆筒 CD,若将悬线剪断,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746296274.png)
则:(1)直杆下端B穿过圆筒所用的时间为多少?
(2)整个直杆AB穿过圆筒的时间为多少?(
)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746296274.png)
则:(1)直杆下端B穿过圆筒所用的时间为多少?
(2)整个直杆AB穿过圆筒的时间为多少?(
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746390618.png)
(1)0.2s (2)0.4s
试题分析:(1)由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746499292.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746796320.png)
B自由下落到C点的时间
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746874371.png)
B自由下落到D点的时间
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145746920443.png)
B穿过圆筒的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145747154380.png)
(2)A自由下落到D的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145747217462.png)
整个直杆AB穿过圆筒的时间为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824145747326390.png)
点评:本题学生能熟练运用自由落体运动的规律去分析问题,在解题的过程中注意加速度g是隐含的已知条件。
![](http://thumb2018.1010pic.com/images/loading.gif)
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