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Homework Help: Speaker hanging from the ceiling

  1. Feb 5, 2009 #1
    1. The problem statement, all variables and given/known data

    A 19.0 kg speaker is suspended 1.6m from the ceiling by two cables each 2.5m in length. the cables come to the top of the speaker and each cable forms and equal angle with the ceiling.

    2. Relevant equations

    i have no idea. i am completely lost.

    3. The attempt at a solution

    the first thing i did was figure out all the dimensions of the triangles that are formed. this has done nothing for me.

    i have read the "hints" offered by the online homework program, and it tells me:

    1) the tension in each of the cables is equal. therefore T1=T2. this is obvious to me just from reading the problem.
    2) the program also said that T1=T2=T*sin of the angle formed by the ceiling and the cable.

    this second step makes absolutely no sense to me. basically, i am trying to solve for the amount of tension in the cable.

    since the cables are at an angle, it seems that each cable should carry more than half of the newtons of the speaker (186.2N).

    i would understand if the computer suggested a formula using the tangent of the angle, but i am completely lost.

    somebody please help.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 5, 2009 #2
    please help. i have a test in a few hours.
  4. Feb 5, 2009 #3
    Draw a free body diagram and resolve along the vertical.
    You will have one force acting downwards, and a fraction of two forces acting upwards.
    As the speaker is in equilibrium, these will be equal and opposite.
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