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Homework Help: Moments and finding the Tension-Help

  1. Sep 8, 2011 #1
    1. The problem statement, all variables and given/known data
    1. The problem statement, all variables and given/known data

    A flagpole of mass 25kg and 2.5m in length is held in a horizontal position by a cable shown in the diagram.
    The centre of gravity of the flagpole is at a distance of 1.5m from the fixed end. Determine:
    a the tension T in the cable;
    b the vertical component of the force at the fixed end of the pole.
    1zn6ik7.jpg



    2. Relevant equations
    Moment=F*perp distance
    vertical component=Fsin(theta)
    Horizontal component=Fcos(theta)
    clockwise=anticlockwise



    3. The attempt at a solution
    I did (a) and I got around 300.Please call out on me if i get this wrong.
    Calculate the moments around the end of the flagpole(left hand)
    clockwise moment=250*1.5=375
    anti clockwise moment=T*1.25
    through division etc, i get 300.



    What i cannot understand is (b) What does it mean by the vertical component at the end of the flagpole?
     
  2. jcsd
  3. Sep 8, 2011 #2

    SteamKing

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    Staff Emeritus
    Science Advisor
    Homework Helper

    What happens when you replace T with its components? BTW, your moment calculation involving T is incorrect.
     
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