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Old 09-12-2011, 01:18 PM   #8 (permalink)
gone-ot
...beats walking...
 
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Quote:
Originally Posted by Patrick View Post
It's been a long time, but I think this is how you solve it algebraically, IIRC.

W1 = initial weight on each side.
W2 = weight to add on light side.
D1 = initial distance to weight on each side.
D2 = distance to weight on light side.

Summation of torques must equal zero.

W1(D1) = W1(D1)
...Patrick is correct, although I believe he meant the "first" basic equation to be:

W1(D1) = W2(D2)

...a simple mnemonic is: "...both strings-lengths have to be equal..." meaning a string from the center out the length of D1, then hanging down (representing weight W1) has to be the same length as D2ŚW2, ...ie: D2 can be ANY length, as long as the remaining W2 'length' totals up to the same 'length' of the W1(D1) side.

...the "other" way to express this "inverse-proportion" relationship is:

W1/W2 = D2/D1

Last edited by gone-ot; 09-12-2011 at 01:26 PM..
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