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Homework Help: The Pendulum

  1. Mar 29, 2010 #1
    1. The problem statement, all variables and given/known data

    Imagine a pendulum which consists of a particle like bob of mass m suspended by a massless string of length L. Using the following equation

    [tex]T=2 \pi \sqrt{\frac{L}{g}}[/tex]

    given the mass of the bob is 100 g, what is the length of the pendulum supposed to be if we want its period to be 2 seconds?

    3. The attempt at a solution

    So do I need to substitute g=9.81 or do I need to use the mass to find a new value for g? Is the follwoing correct:

    [tex]2=2 \pi \sqrt{\frac{L}{9.81}}[/tex]


    I didn't even need to use m=100! Then why did they give us the value for mass if it was useless? am I missing something?
  2. jcsd
  3. Mar 29, 2010 #2


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    Homework Helper

    The period of the simple pendulum is independent of the mass of the bob.
  4. Mar 29, 2010 #3
    Then is my answer correct?
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