Solving a Three-Force Member Equilibrium of Particles Question

[Melawrghk]

Homework Statement

Homework Equations

None

The Attempt at a Solution

The prof told us to treat the three-force member as an equilibrium of particle question. So here is the FBD and the triangle I set up for the particle equilibrium:

I don't know where to go from there.. I mean I know it's a right angle triangle, where I know the hypotenuse, but that's really it. Help? :)

 

[PhanthomJay]

Your first FBD is good. It is usually best to break up the known (3kN) and unknown (A and B) forces into their x and y components. Then just use the 3 equilibrium equations (sum of x forces =0, sum of y forces = 0, and sum of moments about any point = 0) which will give you the required 3 equatiions to solve for the 3 unknowns A, B, and alpha.

 

[Melawrghk]

Thanks Jay. I know how to do it with the equilibrium equations actually. But I'm having problems doing it using the three-force member theory...

 

[PhanthomJay]

Thanks Jay. I know how to do it with the equilibrium equations actually. But I'm having problems doing it using the three-force member theory...

That's a pain theory to use, but if it is required by the problem, the steps are shown here at
http://darkwing.uoregon.edu/~struct/courseware/461/461_lectures/461_lecture15/461_lecture15.html
I've never used the graphical method.