We have three unknowns Fy1, Fy2 and Fx1/Fx3.
Bar has "L" shape and corner is Pin support.
Horizontal is 20" long
Vertical is 5" long
Right side has Horizontal roller at end.
Vertical bar has Vertical roller at end.
Load 30 lbs at middle of the bar (10" away from corner)
I listed out moment equations for each ends, but fomular to get these three, you will have unknows remain.
Software result said
Fy1 = 19.50
Fy2 = 10.5
Fx1 or fx3 = (+/-) 18.00
How to reach to this? What you need to consider to get about balance between Fy1 and Fy2?

Attached Files

result.doc (54.5 KB, 11 views)

Can you elaborate a little? you said that the corner is pinpoint support, but which corner? do you mean that at the bend in "L" shaped bar?

And what's up with the rollers? The image isn't very self-explanatory..like is the bar free to roll along them? but then it won't be fixed at the bend..
Explain these, and then the people here might be of help.

__________________
Any physical theory is always provisional: you can never prove it. But you can always disprove a theory by finding even a single observation that disagrees with the predictions of the theory!

This problem is indeterminate using simply sum of forces= 0 and sum of moments = 0, because you have 4 unknowns and only 3 equations. Which means there are an infinite number of solutions. For example, the following also satisfies the force and moment requirements:

Fx1 = Fx3 = 0
Fy1 = Fy2 = 15

This satisfiies the boundary conditions just as the solution your software gave you does as well. To really solve this you need to incorporate beam deflection equations, but to do that you need to have values for E (Young's modulus), and I (moment of inerta) for each leg. If you assume that EI is infinite, then my solution above is what you get.

Detremine the magnitudes of P and F necessary to keep the concurrent force system in equilibrium.

Attached Images

00000000000000000.jpg (23.6 KB, 3 views)

First - please do not tag a new question onto an old thread - it is better to start a new discussion so as to not confuse things.

To solve this you need to balance the sum of the forces in the x direction to zero, and the sum of forces in the Y direction to zero. I'll help you get started, then you should take it from there and complete the problem.

Sum of forces in X direction = 0 = -300 -P*cos(30)+ F*cos(60) + 200*cos(45)

Do you see how I used cosine to get the component of P, F and the 200 lb load that are in the x direction? Also, note that I used negative signs for forces going to the left and positive for forces going to the right - it's really important to keep the signs consistent and correct.

Now you write out the equation for sum of forces in the Y direction = 0. You will then have two equations with two unknowns, and should be able to solve for P and F. Post back with your results and we'll check it for you.