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Homework Help: Harmonic Motion

  1. Feb 27, 2008 #1
    1. The problem statement, all variables and given/known data

    The motion of an object is described by the equation

    x = (0.90 m) cos(PI*t/5). I needed to find:

    The position of the object at t = 0 and at t = 0.40 s;
    I got (0.9) and (0.8718) meters, respectively, which were correct.
    The amplitude (0.9 meters) was also correct.

    I need to find the frequency (f) of motion.

    2. Relevant equations

    x = (0.90 m) cos(PI*t/5)

    3. The attempt at a solution

    Finding the frequency is the only thing I can't seem to figure out. I tried fiddling with the "cos(PI*t/5)" equation a few ways, but all of my answers are wrong. I think I may be just dividing by the wrong value or something. Could some one give me a head start? Thanks!
  2. jcsd
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