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Homework Help: Pendulum problem

  1. Apr 28, 2005 #1
    Indiana Jones is swinging from a rope. The distance between the pivot point and his center of mass is 31.0 m. He begins swinging from rest at an angle [tex]\theta[/tex] = 17.0 degrees. Assuming the Indiana and the rope can be treated as a simple pendulum, what is the value of [tex]\theta[/tex] after 1.33s (in degrees)?

    i have no idea where to begin on this problem. I know that the formula for a period of a pendulum is [tex] T= 2\pi \sqrt L/g [/tex] , but i dont' know where the angle comes into play. Any help?
     
  2. jcsd
  3. Apr 28, 2005 #2

    Pyrrhus

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    Use the solution to the differential equation

    [tex] \ddot{\theta} + \omega^{2} \theta = 0 [/tex]

    where [itex] \omega = \sqrt{\frac{g}{L}} [/itex]

    For this case you will need:

    [tex] \theta (t) = \theta_{max} \cos (\omega t) [/tex]
     
    Last edited: Apr 28, 2005
  4. Apr 28, 2005 #3
    ok i got it.. thanks
     
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