题目内容
某弹簧原长10cm,如果在它的下端挂60N的重物时弹簧的长度变为12cm。当它缩短1.5cm时产生的弹力是 N,当它受到75N的拉力时,它应伸长 cm。(在弹性限度内 )
45 2.5
由题可知,弹簧受到F1=60N的拉力,伸长是△L1=2cm.当F2=75N,弹簧伸长为:
=
,△L2=
==2.5cm.
当△L3=1.5cm时,受到的拉力:
=
,F3=
=45N.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122851896390.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122852052406.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122852098490.png)
当△L3=1.5cm时,受到的拉力:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122852130361.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122852176417.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824122852223491.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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