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Homework Help: Resultant Couple and direction angle

  1. Feb 1, 2007 #1
    1. The problem statement, all variables and given/known data

    Ok, I have 3 couples applied to a bent bar. The axis is with the z going up, y left and right, and the x basically out of the page(or kinda to the left a bit).

    The pipe goes 28in to the right(on y axis), where the pic show a 100lb force pointing down from the +z direction, and a 125lb force keeps going along the y axis. The pipe then bends and runs parallel with the +x axis, and goes for 16in. A 150lb force from the +x direction points back into the pipe, and a 125lb force points at the pipe from the +y direction. This is also where point A is. The pipe then bends downward(-z) for 9in. At the end of the pipe, a 100lb force is applied towards the +z. A 150lb force is also applied at the end, in the +x direction.

    Determine, the magnitude of the resultant couple C and the direction angles associated with the resultant couple vector. Then also determine the scalar component of the resultant couple C about line O(orgin)A.

    I think I drew this out right.....you just have to draw as you read. Should go towards +y, then towards +x, then -z.

    2. Relevant equations

    I think I add the x,y,z components of the couple(C). Then I think I square each of them, add them together, all under a square root.

    For the angles, I think I just take the cos-1 of each component/mag of C.

    3. The attempt at a solution

    I'm not sure how to find the components. I think I understand how to break them down(simple), but I don't really get how to relate the distance in there. If someone could do one that would be helpful(or explain it). I'm not sure where to take the total distance from I guess either.

  2. jcsd
  3. Feb 1, 2007 #2
    Is this problem understandable?? Or do I need to draw a pic? I didn't draw one on paint, because usually they are too small/blury to see.
  4. Feb 2, 2007 #3
    can anyone help....this is due today. I think I can get it, if I can get some help on how to find the individual components....I'm not sure how to relate the forces, and the distances.
  5. Feb 2, 2007 #4
    Figured it out......thanks for all, that attempted to solve it(I know, it was complicated to read). I even had 2 hrs to go.....haha...Thanks again!
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