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Homework Help: Pendulum Question

  1. Jul 28, 2016 #1
    1. The problem statement, all variables and given/known data
    How would one show that the average total energy of a simple pendulum is equal to twice the average kinetic energy of the pendulum?

    2. Relevant equations
    E = T + V = 1/2 ml**2 (θ'**2) + mgl cos(θ)

    3. The attempt at a solution
    Maybe use equipartition?
  2. jcsd
  3. Jul 28, 2016 #2


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    2017 Award

    Staff: Mentor

    Then you have to show that your pendulum satisfies the assumptions going into that theorem. In particular, your pendulum is not in thermal equilibrium with anything, and a different potential shape will lead to a different result so it does not apply to all pendulum-like systems.

    You can explicitly calculate the average kinetic energy by integrating over one period.
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