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Homework Help: Find tension force of a cable and components of reaction force of pivot

  1. Jul 21, 2012 #1
    1. The problem statement, all variables and given/known data

    Please see attached photos. I've been drawing and re-drawing diagrams but I'm at a loss. For part a, I've tried a right triangle using the top cable as the hypotenuse. I've tried the force equation (ƩF=ma) but I don't think that's right. I just can't get a start.

    2. Relevant equations

    See attached photo with help describing situation. Note also the angle ∅ has been changed from the book's problem from 65 to 55 degrees.

    3. The attempt at a solution

    I've started a diagram but I do not know what formulas to use for the math.
    If you could walk me through the problem that would be great! I have an exam coming up in two days and have no other help in between.

    Attached Files:

  2. jcsd
  3. Jul 21, 2012 #2
    You need to use torque to find the tension in the wire, none of your work or what you mentioned seems to point to using torque.
  4. Jul 22, 2012 #3
    How do I use torque without knowing the distance in this formula? torque=F times distance
    Also, how do I draw a diagram for each part of the problem?
  5. Jul 22, 2012 #4
    Use [itex]\ell[/itex] in your formulas, since they don't give you a length most likely it will drop out.

    For a diagram, draw the rod and label all forces on it, with the angles included. They more or less gave you a diagram, so all thats left to do it label the forces and angles more clearly.
  6. Jul 22, 2012 #5
    Okay, thanks so much!!!
    I'll try that now.
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