Show Energy Equality of Simple Pendulum with Equipartition

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To demonstrate that the average total energy of a simple pendulum is twice its average kinetic energy, one can apply the equipartition theorem, ensuring the pendulum meets the necessary assumptions. The pendulum's lack of thermal equilibrium is crucial, as different potential shapes can yield varying results. Calculating the average kinetic energy requires integrating over one complete period of motion. This approach confirms the relationship between total energy and kinetic energy in the context of simple harmonic motion. The discussion emphasizes the importance of understanding the system's conditions for accurate application of theoretical principles.
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Homework Statement


How would one show that the average total energy of a simple pendulum is equal to twice the average kinetic energy of the pendulum?

Homework Equations


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



The Attempt at a Solution


Maybe use equipartition?
 
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Glenda said:
Maybe use equipartition?
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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