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Homework Help: Two and Three force members

  1. Apr 15, 2010 #1
    1. The problem statement, all variables and given/known data

    Hi, Ive been looking over this problem and I cant manage to find a suitable approach to such a question :S maybe you could help me out. The structure can be seen in the given image.

    As shown, a load of magnitude is applied to a structure. Assuming that all members are weightless and that ABEF and BCD are rigid bodies, find the magnitudes of the reactions at D and G needed to maintain the structure in equilibrium.

    Assume the following values: a = 4.50m , b = 3.00m , and P = 110N .

    2. Relevant equations

    Equilibrium equations..

    3. The attempt at a solution

    No attemps..

    Attached Files:

    Last edited: Apr 16, 2010
  2. jcsd
  3. Apr 16, 2010 #2
    thanks for the overwhelming help :D i managed to work it out by myself.
  4. Oct 27, 2010 #3
    I know you did this problem long ago, but if you still understand how to do it, could you please explain? I am very lost
  5. Mar 1, 2011 #4
    where could i find how to this problem?!
  6. Mar 1, 2011 #5


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    Hi, Ady1219, welcome to Physics Forums! :smile:
    Looks like lmck33 couldn't wait a day for the help, so he may still be a bit heated. Hint: Can you identify a 2 force member in this problem? There are two of them. A 2-force member is one in which forces are applied at the ends of the member only, with no forces in between, and as a result, the 2 forces on these members must be equal and opposite and point toward each other from one end to the other, from equilibrium considerations.
  7. Apr 7, 2012 #6
    Hi guys

    I really need help with that Question, I really don't how to find the reaction force acting D and G. I have Identified all the 2 and 3 force members so far but still haven't got enought skill to find the solution.

    anyone keen to explain to me will be great !.
  8. Apr 7, 2012 #7
    The key to this problem is to understand the difference between the hinge at E and the hinge at F. Whereas ABEF is a bar with various moments in it, especially at E because it is continuous there, F is different. What do you know about the bending moment at F? How does that help you find the reaction at G?
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