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Homework Help: What do you do when time is present in Lagragian Equation?

  1. Nov 26, 2006 #1
    I set up a Lagragian equation that involves time t. What do I do? I only know how to solve Lagragian equation in the absence of time. Please help.
     
  2. jcsd
  3. Nov 26, 2006 #2

    OlderDan

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    Here is one example. If you can justify the throw-away in section 1.3, perhaps you can do something similar.

    http://physics.technion.ac.il/~avron/classical-mechanics/kapitza-wbct.pdf [Broken]
     
    Last edited by a moderator: May 2, 2017
  4. Nov 26, 2006 #3
    I understand the throw away, but when I differentiate

    dL/dq - d/dt (dL/dq dot) = 0

    do I care about time at all?
     
  5. Nov 26, 2006 #4

    OlderDan

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    If your (dL/dq dot) is a function of time, then why would you not care? I think once you have the simplified Lagarangian you do what you always do. It's been a long time since I did this stuff, but I don't see any reason to deviate from the example.
     
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