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Thu 7 May, 2009 04:37 am
I am having an argument with a puzzle publisher....please look at this picture.
http://www.flantoons.co.uk/mike.jpg
I say you need a pull-up force of 6 to keep the bar level.....but the editor says you only need a pull-up force of 3...because it is 2 feet from the pivot.....who is right?
Thanks.
Mike Flanagan
You are wrong...
The distance from the pivot multiplied by the force must be the same on both sides, to keep the bar level.
As so,
6x1 = (6-3)x2..
Therefore the force must be 3..
We actually cannot calculate the answer, because we do not know the mass of the lever.
Ignoring the weight of the lever itself, Francis is correct.
Also, the weight on the left is pulling the lever down, which will cause the lever on the other side to rise.
You need to press down on the right side in order to keep the bar level.
Oops. I missed that the "6" on the right side is a weight as well.
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