VIII. An L$-$shaped bar structure is fixed on the ground, as shown in Figure $5.$ The vertical solid bar has a radius of $10$ mm $,$ and the horizontal bar's radius is $5$ mm $.$ The structure is statically loaded with $1000$ N and $1500$ N $,$ as shown.

$($a$)$ Determine the magnitudes and directions for all stresses at point A$.[12\backslash \%]$

$($b$)$ Please find the absolute maximum shear stress at point A$.[3\backslash \%]$

Hint: All stresses contributed by bending moment, torsional moment, internal normal force, and shear force must be considered.

Section $\backslash ($ a$-$a $\backslash )$