(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A linear chain consists of N identical particles of mass m are connected by N+1 identical, massless springs with force constantk. The endpoints are fixed to walls on each side. In the static configuration each spring is stretched from its relaxed lengthl_{0}to a new lengthl. Construct the Lagrangian for general small oscillations in a plane and show that the transverse and longitudinal modes decouple. Discuss how the frequencies depend onl-l_{0}. Discuss and interpret the behavior forl<l_{0}.

2. Relevant equations

[itex] T = \frac{1}{2} \Sigma m_{\alpha} v^{2}_{\alpha} [/itex]

[itex] U = \frac{1}{2}\textit{k}(\textit{l}-\textit{l}_{0})^{2} [/itex] I think

L = T - U

3. The attempt at a solution

I'm having a hard time deciding on the best way to define my coordinates and how they all relate to each other. I know that once I have that figured out I must assume that the x and y displacements are small and use a Taylor expansion. If there are no cross terms or x and y, then the longitudinal and transverse waves must be decoupled. I think I just need the right picture to be drawn.

Thanks for all of the help!

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# Homework Help: Oscilations of a linear chain of masses and springs

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