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Homework Help: Equation Confusion

  1. May 10, 2008 #1


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    I've come across a equation and I don't understand whether [itex]T[/itex] is Time/s or Tension/N. Can someone explain this equation:

    [itex]T = 2 \pi \sqrt{\frac{l}{g}}[/itex]

    Thanks in advance.
  2. jcsd
  3. May 10, 2008 #2
    That would be the equation for the simple harmonic motion of a hanging mass on a pendulum.

    T denotes the period of oscillation,
    l the length of the string on which the mass hangs.

    Notice that the period doesn't depend on how "wide" the mass swings.
  4. May 10, 2008 #3
    it is time. In fact period. Put the units for them and calculute the final result.

    l : m/s
    g: m/s^2

    (m/s) / (m/s^2) : s
  5. May 10, 2008 #4


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    Isn't Period equal to:

    [itex]P = \frac{1}{T}[/itex]

    So to calculate time of oscillation, [itex]T[/itex] would need to be made subject.
  6. May 10, 2008 #5
    frequence : 1/s
    period : s
  7. May 10, 2008 #6


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    Science Advisor

    No, a "period" is a certain length of time and so has the same units as T (whatever "T" means here). The formula you give is for "frequency"- the number of times the pendulum swings during 1 second and so has units of "1/sec".
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