1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    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!

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


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    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?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook