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kiuhnm

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- Thread starter kiuhnm
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kiuhnm

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- #2

BvU

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- #3

kent davidge

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The only external force is gravity, which is conservative. There follows the calculations.

- #4

kiuhnm

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OK, thanks. I was confused by the remark "This trivial problem emphasizes that the forces of constraint--here the tension in the rope--appear nowhere in the Lagrangian formulation."

Let's say I want to be extremely formal. How would I proceed? The constraint is ##x_1+x_2=l##, where ##x_i## is the position of the ##i##-th mass. How do I deduce from that, analytically, that the sum of the constraint forces is ##0##?

edit: On second thought, I think the pulley is there just to physically justify the constraint. The pulley is massless and frictionless so the text of the problem is basically saying to ignore it and identify it with the constraint.

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