1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Replace all the loads on the beam with one resultant force.

  1. Aug 31, 2013 #1
    1. The problem statement, all variables and given/known data

    Knowing the distance d=1.5m, determine the resultant of the loads acting on the beam shown in the attachment. Specify the point of application of this resultant on the beam.

    Given data: F1=100KN, l1=1m. F2=50kN,l2=1.5m. F3=60KN, l3=4m.
    Variables: Resultant Force R, and its lever arm L.

    2. Relevant equations

    R=F1+F2-F3=90KN(Pointing downwards)
    Take the most left point as reference:
    M=-F1*l1-F2*l2+F3*l3=65 KN*m (Counterclockwise direction)

    3. The attempt at a solution
    The problem I have is that, since R is pointing downwards, it will never create a counterclockwise direction moment, hence this problem cannot be solved. But on my book, anwser is given like this:
    R=90KN downwards @0.722m from the left end

    Thank you for helping me:)

    Attached Files:

    Last edited: Aug 31, 2013
  2. jcsd
  3. Aug 31, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    You have the 50 kN load located at 4m from the left end. This location does not match the attached diagram.
  4. Aug 31, 2013 #3
    Sorry for my mistake, corrected just now
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted