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Centripetal force on table.

  1. Oct 17, 2009 #1
    1. The problem statement, all variables and given/known data
    hi guys i need help solvign the following problem.

    A mass 1kg on a frictionless table is attached to a hanging mass 4kg by a cord through a hole in the table. Find the frequency with which 1KG mass must move for 4kg to stay at rest, if the radius of the circle is 75m.

    http://img32.imageshack.us/img32/9601/phyp.jpg [Broken]

    2. Relevant equations


    v = 2piR/T

    T = 1/f

    ac = 4pi * R/ T2
    3. The attempt at a solution

    Well i dont really know where to start as there is no angle given so i found the circumference first. which is 4.71 or 471 cm.

    I think that is useless because i dont know what to do with it. I know i need to find ac first before i can find the frequency right?

    So can someone give me a hit on the first step or where to start?

    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Oct 17, 2009 #2


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    Homework Helper

    This is more of a force problem than a harmonic motion problem. Try writing out Newton's second law for both the 1 kg mass and the 4 kg mass. Remember that for an object moving in a circle at speed v, acceleration=v^2/r. Also note that the tension in any massless rope is constant throughout the rope.
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