The system shown in the figure is composed of members $[1],[2],$ and $[3]$ and loaded by a known couple of $10$ N$-$m$.$

Here are the free body diagrams for subsystems $(1)$ and $(3).$ Note that member $(2)$ is a two force member.

The unknown Ay can be solved for using only two steps $($solving only two equations$).$ For each of these two steps, specify the body whose equilibrium should be considered, the equilibrium equation that should be used, and the unknown that should be solved for from this equation.