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Does damping of period affect the period?

  1. Apr 29, 2010 #1
    Hi there,

    Sorry typo in the title and I can't figure out how to change it!
    I am just wondering if anyone can help me - does damping (drag) increase the period of a pendulum? As opposed to if it was in a vacuum?

    I have been trying to figure this out for some time - I know that drag is dependent on the velocity of the period, but does it actually change the period?

    I am giving a presentation on how the period of a physical pendulum increases as the mass distribution changes (centre of mass lowers, the effective length gets longer) and I was once told by a lecturer that damping does not in fact change the period, but I don't see how? Surely it would slow it down, thus increasing the period?

    Would greatly appreciate any thoughts on this!

    :)
     
  2. jcsd
  3. Apr 29, 2010 #2
    In general, over damping and critical damping of the system produce non-periodic motion.
    Under damping will produce a frequency that is less than the natural frequency by an amount that depends on the "damping ratio".
    Plenty of information here
    http://en.wikipedia.org/wiki/Damping#System_behavior
    For air pendulums the amount of damping is very small, resulting in a negligible decrease.
     
  4. Apr 29, 2010 #3

    Vanadium 50

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    Imagine a pendulum in honey. Will it take longer for it to make a full oscillation?
     
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