Problem with Lagrange first kind equations

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The discussion revolves around using Lagrange's first order equations to find the equilibrium point for two masses constrained to concentric circles and connected by a solid rod. The user presents their Lagrangian, which includes kinetic and potential energy terms, but struggles to derive the equations of motion correctly. They express confusion regarding the constraint and seek clarification on their approach and the form of the Lagrangian. Other participants point out potential errors in the user's notation and suggest reviewing the kinetic terms included in the Lagrangian. The conversation emphasizes the importance of correctly formulating the Lagrangian to solve the problem effectively.
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Homework Statement


Two masses move in a plane restricted to concentric circles with radii R1 and R2. They are joined by a solid rod of length B. Use Lagrange first order equations to find the equilibrium point


Homework Equations


Constraint due to the solid bar: B = R12 + R22 -2R1R2cos(θ1 + θ2), where θ1 and θ2 are the polar coordinates of the masses.

The Attempt at a Solution


My Langrangian is as follows: L = (m/2)(R12ω12+R22ω22)-mg(sinθ1+sinθ2)
By substituing in this expression http://en.wikipedia.org/wiki/Lagrangian_mechanics#Lagrange_equations_of_the_first_kind I find two equations of motion:
-mgcos(θ1)+mR12+α1 + R1R2sin(θ1 - θ2)λ1 = 0
-mgcos(θ2)+mR22+α2 - R1R2sin(θ1 - θ2)λ2 = 0
where α1 and α2 are the angular accelerations of the masses, and the λs are the Lagrange multipliers. I can't solve this equations, though. Is there any method of solving them that I cannot find or is it that my whole procedure is wrong?
 
Last edited:
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Can you show us what your Lagrangian looks like, that you use to derive these equations of motion?
You denoted the constraint by ##L##, but I don't think that expression is your Lagrangian because I don't see a kinetic term.
 
Sorry, its a bit confusing because the length of the bar is L. I'll change it to B and edit the rest.
 

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