Hello guys. This is not really a homework exercise, but I'm currently preparing for an(adsbygoogle = window.adsbygoogle || []).push({});

exam and this is a question I got from a textbook. I'm currently sort of stuck,

but here are the details.

1. The problem statement, all variables and given/known data

Link to a scan of the problem:

http://img443.imageshack.us/img443/4593/question1y.png [Broken]

2. Relevant equations

The problem is supposed to be solved by using the Lagrangian Method.

(Since it's from a "theoretical-mechanics"-book)

3. The attempt at a solution

Okay. What I thought was that i have to choose a suitable accelerating coordinate system

and relate this coordinate system with an intertial frame of reference.

First one sees in the picture that:

l * q(t) = s(t) * l_1(t)

So if one finds an equation of motion for l_1(t) one is done.

Now the problem is I'm not sure which moving coordinate system to choose.

I could choose one with origin at B, which would mean that there's gravity but

only the spring-force acting on the mass m.

However I'm not quite sure how to tackle this problem in general and I'm a bit confused.

I'd be more than happy if you could help me!!

Thanks in advance!

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# Homework Help: Falling Oscillator

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