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Physics/Mechanics Equilibrium Force Question

  1. Sep 9, 2010 #1
    1. The problem statement, all variables and given/known data
    Find the reaction forces of A and B.
    Uniform bar with a mass of 100kg/m supported by a pin and a roller.
    [tex]\Theta[/tex] = 60
    g=9.81m/s2
    [URL]http://img340.imageshack.us/i/mechanicsproblem.jpg/[/URL]
    http://img340.imageshack.us/i/mechanicsproblem.jpg/

    2. Relevant equations
    Moment/torque = Force*Displacement
    Sum of MA=0 (moment about point A)
    Sum of FY=0
    Sum of FX=0

    3. The attempt at a solution
    Taking M about point A. (Counter-clockwise as +ve)
    9BY - (1500N*7m) - (2400N*sin(60) * 3.5m) - [100kg/m*9m*9.81m/s2*(1/2*9m)]=0
    9BY = 57,505N
    BY = 6.389kN
    B = 6.389kN

    Sum of FY=0
    AY + BY - 2.4kN*sin(60) - 1.5kN - (W=8.829kN) = 0
    AY = 6.018kN

    Sum of FX=0
    AX - 2.4kN*cos(60) = 0
    AX = 1.2kN
    Would like to verify whether my attempt at the question is correct, as well as my free body diagram.
     
    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Sep 10, 2010 #2
    A diagram for the question would help.
     
  4. Sep 10, 2010 #3
    Sorry, Iv'e just found the link to the figure. Your fbd is not correct at the left hand load. Something missing there. You can check your own work by taking moments about any point other than A.
     
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