A steel girder has a closed rectangular cross$-$section with the dimensions given in Figure Q$3.$

The girder has a $24$ m span and is simply supported at the two ends. A w kN$/$m uniformly

distributed load is applied on the girder.

Solve the following questions:

$($a$)$ Find the neutral axis of the girder.

$($b$)$ Calculate the second moment of area of the girder.

$($c$)$ If the maximum shear flow on each side of the top flange$-$web connection is equal to $1\mathrm{.}8$ kN$/$mm$,$ calculate the maximum shear force acting on the girder.

Where:

X$1=221$ mm

X$2=192$ mm

X$3=254$ mm

Please write through pen and paper.