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Homework Help: Graphing pendulum function

  1. Jan 23, 2005 #1

    Ive done the first part of a question which was to derive the equation

    [tex]\displaystyle{\theta(t) = \theta_0 \sin(\omega_0t + \phi)}[/tex]

    for a pendulum

    where [tex]\displaystyle{\omega_0 = \sqrt{\frac{g}{r}}}[/tex] and [tex]\displaystyle{\phi = \sin^{-1} \left(\frac{\theta_1}{\theta_0}\right)}[/tex]

    [tex]r = \mbox{length of rod (pendulum)}[/tex]

    The next part says

    Sketch [tex]\theta(t)[/tex] versus [tex]t[/tex] for the cases [tex]\phi = 0[/tex] and [tex]\displastyle{\phi = \frac{\pi}{2}}[/tex]

    How do I do this if i dont know [tex]\theta_0[/tex] or [tex]r[/tex]? I know they are both constant though, does this have a bearing on the situation?

    Last edited: Jan 23, 2005
  2. jcsd
  3. Jan 23, 2005 #2


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    1.There's a typo in the first formula.A "t" is missing in the (round) bracket...

    2.The graph is basically a streched (on "y") sinusoid...So it ain't a big deal to draw it.You have to determine the amplitude,the zeros and that's it...

  4. Jan 23, 2005 #3

    Ok, so im just basically sketching it and trying to make it look nice

    I think i can do that :smile:

    Thanks again
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