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Statics in traingles, or trusses

  1. Jan 19, 2012 #1
    Hi there,

    I have been given the questions below as part of some revision before we begin mechanics next term. I have looked back through my notes and I seem to be missing the notes on calculating the forces.

    So far I know
    XZ = 9.49m
    ZY = 4.24
    Angle x = 18.4
    Angle y = 45
    Angle Z = 116.6

    I think the value of force in XY is -5Kn but I am struggling to calculate the force in rafter XZ.

    Any help would be appreciated =D and thanks in advance

    Attached Files:

  2. jcsd
  3. Jan 19, 2012 #2


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    As a general rule, find reaction forces first by summing moments of external forces, known and unknown (applied and reaction forces), about one support, = 0. You can then sum moments about the other support or use sum of forces in y direction = 0 to get both reaction forces. To then get the forces in the members, you should look up the method of joints, and start at the easiest joint. Your answer is not correct.
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