this is a system of three masses attached to a string, hanging on two fixed pulleys.(adsbygoogle = window.adsbygoogle || []).push({});

I want to find the equation of motion of the middle mass, given the initial condition P(0)=X

Assuming all friction, stretching of the strings, and momentum of the pulleys are negligible.

The string has a fixed length overall, the length of string between masses is equal, and the masses are also equal.

I get confused because I'm trying to keep track of too many variables, there are 4 angles, 3 tensions, 3 positions... I know there's a better way to do this, any help would be appreciated.

here's a diagram I made... thanks for any help!

[PLAIN]http://img828.imageshack.us/img828/1610/3mass2pulleysystem.jpg [Broken]

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# Mechanics, 3 coupled masses. don't worry, no springs!

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