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How is torque shared?

  1. May 15, 2015 #1
    Hey there, I'm trying to figure out how torque operates in combination and I can't find anything relating to this in any textbooks or online.

    So if you a mass held by two strings in equilibrium, the force of gravity is split evenly between them right?
    What happens if you have torque instead of a linear force?

    A common example I have seen when looking around is that if you have three masses at known distances on a see-saw in equilibrium and you know two of the masses you can solve for the third.
    But now what happens if you have a system in equilibrium where you apply a torque on one side of the see saw which is opposed by two forces at different distances on the other?

    I came up with a concrete example in the figure below so it is more clear.

    Are the forces equal or are the torques equal? Or perhaps neither?

  2. jcsd
  3. May 15, 2015 #2


    Staff: Mentor

    For an object to be in static equilibrium both the forces and the torques must sum to 0.
  4. May 15, 2015 #3
    Right this is what I've been using to try to figure it out but I get stuck with something like x+y=T where x and y are unknown.
  5. May 16, 2015 #4


    Staff: Mentor

    Yes, it is possible to have a system where you have too many unknown forces to solve. Such a system is known as "statically indeterminate".

    In order to solve such a system you have to include the material properties of the beam and calculate the amount of stress and strain. This adds additional equations and gives you a system you can solve.
  6. May 16, 2015 #5
    Awesome, thank you so much!
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