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Homework Help: Pendulum and Gravity

  1. Nov 19, 2005 #1
    Alright so here’s the problem. In lab we are supposed to come up with a way to figure out gravity using an experiment. The experiment that I came up with is to use a pendulum and find its period and then calculate the gravity. I know this is possible but I don’t know the equations. If anyone can help me out with the equations for this type of problem it would be much appreciated. Also, would it be better to do a few different string lengths or keep the string length constant?
  2. jcsd
  3. Nov 19, 2005 #2


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    The period of a simple pendulum is

    [tex]T=\pi \sqrt{ \frac{L}{g}}[/tex]

    With L being the length of the pendulum.

    I would use the longest string you possibly can.
  4. Nov 19, 2005 #3


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    Remember, that expression,

    [tex]T=\pi \sqrt{ \frac{L}{g}}[/tex]

    is an approximation and is accurate only for small oscillations, where [tex]sin\theta \approx \theta[/tex]

    That's why you should use as long a string as possible, so as to keep the amplitude of oscillation as small as possible.
  5. Nov 19, 2005 #4
    Thanks... I need to run the expirement again. If I have any more questions I'll be sure to ask.
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