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

Which is more linear, a frictionless or slightly frictional pendulum clock?

  1. Sep 20, 2004 #1
    A pendulum (clock) is moderately nonlinear for small angles of displacement. Is simple harmonic motion better approached by introducing a degree of friction into its works?
  2. jcsd
  3. Sep 20, 2004 #2


    User Avatar
    Science Advisor
    Homework Helper

    I'm not sure what you mean by "moderately nonlinear" but, no, you won't change the way that the nonlinear "restoring force" behaves by adding damping. Perhaps you're confusing "nonlinear" with "unstable?"

    Incidentally, the expression "simple harmonic oscillator" refers ONLY to a system with a linear restoring force and is often used in the small angle approximation to a pendulum.
  4. Sep 20, 2004 #3

    I helped a young man construct a 2-D pendulum whose bob traces out in sand its displacement vs time. It swings discernably for about ten cycles (a total of ~17 seconds), leaving both a record of its displacement and the number of periods. Is it a safe, albeit rough, approximation to use the linear period equation T=2pi(L/g)1/2 when such friction is involved?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook