$($a$)$ A SHORT column with a hollow$-$section is subjected to an eccentric compressive force as shown in Figure Q$3$a$.$

$($i$)$ Determine the bending moments, $M_{}$ and $M_{yy},$ cross$-$sectional area and moment of inertia, $I_{}$ and $I_{yy},$ of the cross section about the centroidal axes.

$(7$ marks$)$

$($ii$)$ Determine the maximum and minimum stresses in the section.

$(8$ marks$)$

Figure Q$3$a