A very simple moments question

[kuruman]

Now that we have come to the end of the discussion, Im not sure how you end a tread, do you just stop replying, or do you click something to end it?

Just stop replying if you so desire. You cannot "click something to end it" because others may wish to continue the discussion with or without you. Only the gods, a.k.a. mentors, can close threads.

 

[A.T.]

I am not sure what the system "as a whole is."

I am not sure either what @Lnewqban means by that, but it sounds like both bars + attached weight.

I have considered two separate systems

But in either case Fy was the force by the wall on the horizontal bar only.

 

[kuruman]

I am not sure either what @Lnewqban means by that, but it sounds like both bars + attached weight.


But in either case Fy was the force by the wall on the horizontal bar only.

Yes, of course. The horizontal bar doesn't give a hoot about what we choose as "the system" as long as the "gallows" configuration remains unchanged. If the diagonal piece just touched the wall without being fastened and the contact were frictionless, then $F_y$ would be equal to the hanging weight.