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Homework Help: Acceleration of gravity at pendulum

  1. Jan 7, 2008 #1
    1. The problem statement, all variables and given/known data
    A pendulum which is 2.00m long makes 84.5 complete oscillations in 4.00 min. What is the acceleration of gravity at that spot? Show all work and formulas.

    2. Relevant equations

    T=2(3.14) SQRT(l/g)

    3. The attempt at a solution

    L= g*(T/2pi)^2
    g=4.9298 m/s

    I'm not sure if i'm missing a step, or if this is correct.. which is where I run into the problem. I'm also not sure of where the Oscillations would fit in.
  2. jcsd
  3. Jan 7, 2008 #2


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    T is the number of seconds per oscillation. You can figure this out with the data given.
  4. Jan 7, 2008 #3
    So it would be 4/84.5= 0.047 minutes per oscillation = 2.84 oscillations per second?
    Last edited: Jan 7, 2008
  5. Jan 7, 2008 #4


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    2.84 seconds per oscillation, yes.
  6. Jan 7, 2008 #5
    If you're trying to find g, wouldn't it be easier to solve the equation for g immediately? But that's not the main problem. The 4 mins is not T, it is the time it takes for 84.5 oscillations, not 1.

    EDIT: lol sorry too late :D
  7. Jan 7, 2008 #6
    Ok, I got it, thanks a bunch! =)
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