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Homework Help: Engineering Mechanics: Force couple

  1. Oct 23, 2014 #1
    1. The problem statement, all variables and given/known data
    Problem is:
    Replace the 150-N force with an equivalent force-couple system at A
    Since it is really hard to describe the scenario in words, attached is a link that shows the diagram of the question.

    2. Relevant equations
    Cross Product and sum of forces

    3. The attempt at a solution
    So I have the feeling I screwed up somewhere. What I did was I first converted the force into its components, producing me with -150cos35j+150sin35k. Since one of the things that the question asked was for I just simply took -150cos35 and 150sin35. I then decided to find the D which yields me (-0.1m)i+(0.12m)j+(-0.2m)k. Since the moment is equal to FxD, I took the cross product of these two values to produce me a value of (14.25N m)i+(-8.6N m)j +(-12.29N m)k. I have the strange feeling it is wrong and I screwed up somewhere. Can anyone help me with the problem?
  2. jcsd
  3. Oct 24, 2014 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Check the direction of the components of the force. Look at the coordinate axes to make sure the components are oriented in the correct sense.
  4. Oct 24, 2014 #3
    Ah I see now! Thanks!
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