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Homework Help: Moment of force

  1. Dec 24, 2015 #1
    1. The problem statement, all variables and given/known data
    Calculate resultant moment of forces about pt O and state its direction.

    2. Relevant equations
    Put the picture. Check it out

    3. The attempt at a solution
    What I did was :
    About A : 60Nm
    B: 40 Nm
    C : 120Nm.

    I'm not sure to add or subtract for resultant. What I did::
    Add. A-B as they are in same direction : 60➕40 : 100
    Then subtract 120 to it as opposite direction direction

    Therfore. 20 Nm

    Am I right about the resultant or totally wrong?

    Direction : Clockwise.

    Attached Files:

  2. jcsd
  3. Dec 24, 2015 #2


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    Science Advisor
    Gold Member
    2017 Award

    You are correct. You should specify that it is clockwise around the axis coming out of the page. In complicated situations, you define a right-hand coordinate system. Then your moments around an axis have the appropriate sign and you don't have trouble keeping track of clockwise, counterclockwise around which axis.
    Last edited: Dec 24, 2015
  4. Dec 24, 2015 #3
    Alright. Thanks :)
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