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    So, I've a problem that says:

    A particle of unit mass moves on teh positive x-axis under the force
    F = 36(x^-3) - 9(x^-2).

    Show that in the harmonic approximation the period of oscillation is T = 16pi/3.

    Now, I'm not really sure what is meant by harmonic approximation. Any idea/suggestions/hints?
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    For SHM the (restoring) force must be directly proportional to x. (F=-kx) The harmonic approximation would be the range of values of x for which this is (approximately) true.
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    (Original post by Stonebridge)
    For SHM the (restoring) force must be directly proportional to x. (F=-kx) The harmonic approximation would be the range of values of x for which this is (approximately) true.
    So, I would set the given equation for force equal to -kx?
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    You need to find the zero of F (ie equilibrium), then taylor expand to 1st order about it, which will give the constant k.
 
 
 
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