Determining static equlibrium reactions

I'm having trouble getting my head around how to determine the direction of the forces of reaction and of moment/torque in static equilibrium systems.
For example how do I determine the reactions for the system attachment and why are they as they are.
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 Come on? Cant anyone help me??? This ought to be simple, but surprisingly no one knows.

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 Quote by martix Come on? Cant anyone help me??? This ought to be simple, but surprisingly no one knows.
Well, not that simple. Try isolating BCD and take FBD's of members BC and CD. Note that there can be no moments at joints B, C, and D. Solve for the reactions at B and D, then analyze AB as a cantilever with a distributed load and concentrated load at the far end. Assume small deflections. Note that your units for F are stated incorrectly, it should be in kN, not kN-m.

Determining static equlibrium reactions

I am not familiar with everything the exact English terminology so there may be small discrepancies in what I'm trying to say.
Anyway, didn't notice the F units thing...
Well I do know that the directions do no matter for the internal joints, all that is important is that they are opposite for each joint so as to keep the equilibrium.
The problems I'm trying to solve are usually only about finding the magnitude, they don't involve vector quantities. So thats why I need to determine the direction(i.e. sign in the equilibrium equation) of the forces on the end points. Which for this case are A and D.
But then again - the solution has some negative numbers which don't really make sense to me.
Anyway, thanks.

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