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Homework Help: Reduction of resultant Moment/Force

  1. Jan 4, 2008 #1
    [SOLVED] Reduction of resultant Moment/Force

    So I have calculated the resultant force correctly but my solution for distance is incorrect. I keep getting 6.08 ft but the correct solution is 6.57 feet from B.
    Picture1-4.png

    I found [itex]F_r=798.499[/itex] which is correct. Then I used,

    [tex]\sum M_B=\frac{3}{5}(500)(9)+6(1200)+\frac{12}{13}(260)(4)=4860 lb\cdot ft[/tex]

    Then [itex]d=\frac{M_r}{F_r}=6.09 ft[/itex] Where is my error?
     
  2. jcsd
  3. Jan 4, 2008 #2

    Dick

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    Homework Helper

    F_r is the total magnitude of the resulting force, yes. But in the formula d=M/F (where M is the torque, and d is distance from axis), you want the F to be component of the total force that exerts torque. That would be the vertical component only of the total force.
     
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