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Homework Help: Really simple, system in equilibrium (weight and tension in light string)

  1. Mar 6, 2012 #1
    1. The problem statement, all variables and given/known data

    A small smooth ring R of mass 0.1 kg is threaded on a light string. The ends of the string are fastened to two fixed points A and B. The ring hangs in equilibrium with the part AR of the string inclined at 40° to the horizontal, as shown in the diagram. Show that the part RB of the string is also inclined at 40° to the horizontal and find the tension in the string.

    2. Relevant equations

    3. The attempt at a solution

    I have no difficulties with the second question, namely finding the tension in the string, but although it seems obvious to me that RB should be inclined at 40° to the horizontal, I’m at a loss to prove why in the most coherent way possible. I would be grateful for an outline on how to prove this concisely and effectively. Cheers

    Attached Files:

  2. jcsd
  3. Mar 6, 2012 #2


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    Homework Helper

    It is a single string and the ring slides along it till it reaches equilibrium. The tension is the same all along the string. When in equilibrium, both the horizontal and vertical components of the forces acting on the ring sum up to zero. What are the horizontal force components? (Draw the forces.)

  4. Mar 6, 2012 #3
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