题目内容
(6分)学校科技活动小组的同学们准备自己动手粗略测定铁块与长木板之间的动摩擦因数,已有的器材:长木板、小铁块、米尺和刻度尺.他们同时从实验室借来一个电火花打点计时器,设计了如下实验:
a.用米尺测量长木板总长度
,将打点计时器固定在长木板上。然后将长木板靠在竖直墙壁固定(如图),并测量长木板顶端B相对于水平地面的高度
和长木板底端A与墙角C之间的距离
;
b.将小铁块连上纸带,接通打点计时器后释放,得到的纸带如下图, A、B、C、D、E是纸带上连续的5个点。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025494868676.png)
现用刻度尺直接测出AC、CE的距离分别为:
、
;已知交流电的频率为
,重力加速度为
.由此可求得铁块的加速度
= ;根据牛顿第二定律,可求得动摩擦因数
= (用
、
和测得物理量的字母表示) 。
a.用米尺测量长木板总长度
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549361280.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549377313.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549408258.png)
b.将小铁块连上纸带,接通打点计时器后释放,得到的纸带如下图, A、B、C、D、E是纸带上连续的5个点。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025494868676.png)
现用刻度尺直接测出AC、CE的距离分别为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549720300.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549735331.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549751304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549767273.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549798283.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549813301.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549751304.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549767273.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549876715.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025498911033.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025499071044.png)
试题分析:根据纸带由匀变速直线运动的判别式:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549938613.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549938549.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549954807.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549969297.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002549985932.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002550001641.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002550016610.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250025500321738.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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