# Two and Three force members

1. Apr 15, 2010

### Lmck33

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..

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Last edited: Apr 16, 2010
2. Apr 16, 2010

### Lmck33

thanks for the overwhelming help :D i managed to work it out by myself.

3. Oct 27, 2010

### engineerman01

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

4. Mar 1, 2011

where could i find how to this problem?!

5. Mar 1, 2011

### PhanthomJay

Hi, Ady1219, welcome to Physics Forums!
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.

6. Apr 7, 2012

### oyala

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 !.

7. Apr 7, 2012

### pongo38

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?