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Simple Harmonic Motion Question

  1. Apr 13, 2004 #1
    A body oscillates in SHM according to the equation, x = A cos(wt + f) where A = 8.8, ω = 1.070, and φ = 0.420. Assume all quantities are in SI units. What is the period?

    I dont know how to get the period from this equation? Can anyone lead me in the right direction, please? Thanks! ~Dave W.
  2. jcsd
  3. Apr 13, 2004 #2
    First, I will re-write your equation to avoid confusion:

    [tex] x = Acos(\omega{t} + \phi)[/tex]

    where the quantities are as you stated.

    Now, I can tell you that [tex]\omega[/tex] (the angular frequency) is equal to [tex]2\pi{f}[/tex], where f is the frequency (number of oscillations per second).

    From that, can you find the period?
  4. Apr 15, 2004 #3
    Kinda. I see that [tex] f = \frac{1}{T}[/tex]

    So, from that, I can write:

    [tex] x = Acos(\frac{2\pi}{T}(t) + \phi)[/tex]

    Then, I solve for T:

    but i've now introduced an "x" and a "t" into the problem, where do i go from here?
    Last edited: Apr 15, 2004
  5. Apr 15, 2004 #4

    Doc Al

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    Staff: Mentor

    Don't do that! Instead write the equation for ω (which is given) in terms of T. (I know you can do it, since that's what you just did to rewrite that equation.)
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