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Uniform circle motion question

  1. Oct 21, 2011 #1
    1. The problem statement, all variables and given/known data

    A light string can support a stationary hanging load of 25.0kg before breaking. An object of mass m = 3.00kg attached to the string rotates on a frictionless, horizontal table in a circle of radius r = 0.800m, and the other end of the string is held fixed. What range of speeds can the object have before the string breaks?

    2. Relevant equations

    F = (m*v^2)/r

    3. The attempt at a solution

    I seem to only be able to solve this question in terms of F. As in, the max velocity can be:

    v = (F*0.800/25)^0.5

    Yet there is an actual numeric answer to this question.

    I'm not sure what to do with the '3.0kg' given. Any hints would be appreciated!
  2. jcsd
  3. Oct 21, 2011 #2
    when you spin this 3kg mass, there is a certain amount of tension in the string. The tension in the string cannot exceed 25kg * gravity. So what is the maximum speed you can spin a mass of 3kg so the tension in the string doesn't exceed 25kg * gravity?
  4. Oct 21, 2011 #3
    Ohh, this is the definition of "hanging load"? I understand now! Thank you.
  5. Oct 21, 2011 #4
    You're very welcome:smile:
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