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Homework Help: A simple angular velocity with two spheres problem

  1. Dec 10, 2016 #1
    1. The problem statement, all variables and given/known data
    Two masses have same mass m, both of them are tied by a string and put in a hollow cylinder.
    When the cylinder start to rotate until the angular speed is ω.
    The tension in the string is T and the string breaks, both masses move away from the axis in the hollow cylinder.


    2. Relevant equations

    3. The attempt at a solution
    I have no idea about whether the tension T is equal to mrω^2 or 2mrω^2 (since there is two masses)
    Please help!:cry:
    sorry for my bad english
  2. jcsd
  3. Dec 10, 2016 #2


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    If you pull a spring with a force F, the spring pulls back with a force F. The tension in the spring is F, not 2F.
    Same with a rope. In the situation described, but e.g. also if the rope hangs over a pulley and the two masses both pull down with ##mg##. Tension is ##mg##, not ##2mg##
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