题目内容
(如图甲所示是一个单摆振动的情形,O是它的平衡位置,B、C是摆球所能到达的最远位置.设摆球向右方向运动为正方向.图乙所示是这个单摆的振动图象.根据图象回答:(
)
(1) 若当地的重力加速度为10 m/s2,试求这个摆的摆长是多少?
(2)如果摆球的质量m=0.1kg,在摆动过程中通过O处时绳上拉力F0= 1.01N,则摆球通过O点时的动能Ek是多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042585576016.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258542243.png)
(1) 若当地的重力加速度为10 m/s2,试求这个摆的摆长是多少?
(2)如果摆球的质量m=0.1kg,在摆动过程中通过O处时绳上拉力F0= 1.01N,则摆球通过O点时的动能Ek是多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250042585576016.jpg)
(1)0.16 m;(2)8×10
J
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258557259.png)
试题分析: (1)由图乙可知T=0.8 s
由T=2π
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258573463.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258588628.png)
(2) 设小球到达O点的速度为v,由牛顿第二定律
在0点有: F0-mg=m
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258604437.png)
v=0.4m/s
Ek=
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258635586.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825004258557259.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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