Question $2$: $[20$ marks$]$

A road sign with the layout and dimensions shown below carries a wind load acting in the negative $z-$direction. The sign is fixed at the left support. The resultant force from the wind load has a magnitude of $50kN$ acting at the centroid of the $2\mathrm{.}55m$ rectangular sign. The bar supporting the sign has a solid $250250mm$ square cross$-$section as shown in the closeup view of the fixed connection. The self$-$weight of the assembly can be neglected such that they only load is the $50kN$ force acting as shown. Points A and $B$ are located at the fixed support in the middle of each $250mm$ side of the bar as shown in the main figure and the closeup of the support at right.

$($a$)$ Determine the internal shear force, bending moment, and torque acting in the solid bar at the fixed support due to the wind load. $[8$ marks$]$