Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Quick Question on Harmonic Motion

  1. Apr 3, 2010 #1
    Is the oscillation period T ( T = 2╥ * sqrt(M/k) ) independent of the Amplitude of the motion? I mean the equation shows that it is but I'm not totally convinced.

    For example, if a massless spring of k = 6 and M = 0.04 has the mass pulled down (i) 0.04m and then (ii) 0.10m. Will the oscillation period T be the same for both amplitudes (i and ii)?

    Thanks in advance for any help.
  2. jcsd
  3. Apr 3, 2010 #2


    User Avatar
    Science Advisor

    For an ideal harmonic oscillator, yes, the frequency is independent of the amplitude. Of course, no real system is ideal - i.e. massless springs do not exist. So in practice any real system has a frequency that depends on the amplitude.
  4. Apr 3, 2010 #3


    User Avatar
    Science Advisor

    Indeed! This is one of the big to-do's about harmonic oscillators! The frequency of oscillation (or equally, the period) does not depend on the initial conditions! Phyzguy points out one regime where a system fails to be a harmonic oscillator. Others include a pendulum where the displacement is not small, or a spring which is stretched so much that hooke's force law is no longer accurate.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook