Why is a simple pendulum not a perfect simple harmonic oscillator?

Huzaifa · Feb 3, 2022

Khan Academy claims that a simple pendulum not a perfect simple harmonic oscillator. Why is it so?

jbriggs444 · Feb 3, 2022

Huzaifa said:

Khan Academy claims that a simple pendulum not a perfect simple harmonic oscillator. Why is it so?

Is the restoring torque exactly proportional to the angle of the pendulum? What happens if the angle gets big?

hutchphd · Feb 3, 2022

Because the restoring force is not exactly (negatively) proportional to the displacement.

Baluncore · Feb 3, 2022

Here are some better approximations for the period.
http://www.leapsecond.com/hsn2006/pendulum-period-agm.pdf
http://www.leapsecond.com/hsn2006/

kuruman · Feb 3, 2022

Yes, the simple pendulum is not a simple harmonic oscillator for reasons already explained. However, Christiaan Huygens's pendulum follows the tautochrone curve which is not as simple as a circle but has amplitude-independent period, i.e. is a simple harmonic oscillator.

Why is a simple pendulum not a perfect simple harmonic oscillator?

Discussion

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