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Homework Help: Are the following equations inversely or directly proportional to frequency?

  1. Apr 14, 2012 #1
    1. The problem statement, all variables and given/known data

    Re-arrange the eqation Fc=4π²mrf² to solve for frequency (f). State the relationship between frequency and (radius, mass, Fc).

    2. Relevant equations

    3. The attempt at a solution

    [itex]\frac{Fc}{4π²mr}[/itex] = f²
    [itex]\sqrt{\frac{Fc}{4π²mr}}[/itex] = f

    I have re-arranged the equation though now I need to know the relation between:
    •frequency vs radius (r)
    •frequency vs mass (m)
    •frequency vs Fc (Fc)

    Which one is proportional and which ones are inversely proportional? (does the square root affect them)?
  2. jcsd
  3. Apr 14, 2012 #2
    Just forget that there was a square root sign. You'd have Fc / 4n^2 * m * r.
    The Square root does reduce the value of the expression inside, but does nothing to the relationships that you are looking for

    If you brought the bottom over, then it becomes clear that Fc is directly proportional to frequency, and that everything else is inversly proportional to frequency.
  4. Apr 14, 2012 #3
    Thank you very much! The square-root was getting to me :) lol.
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