题目内容
从斜面上某一位置,每隔0.1 s释放一颗小球,在连续释放几颗后,对在斜面上滑动的小球拍下照片,如图所示,测得xAB=15 cm,xBC=20 cm,试求:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001338937665.png)
(1)拍摄时B球的速度大小.
(2)A球上面滚动的小球还有几颗?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001338937665.png)
(1)拍摄时B球的速度大小.
(2)A球上面滚动的小球还有几颗?
见解析
试题分析:(1)B球的速度vB等于AC段上的平均速度,即有vB=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001339030717.png)
(2)由△x=aT2得:小球下滑的加速度a=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001339046537.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001339061704.png)
由vB=at得,B球运动的时间为t=0.35s,由于T=0.1s,则A球上面滚动的还有2颗小球.
![](http://thumb2018.1010pic.com/images/loading.gif)
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