$2-$ The beam cross section shown below has a variable wall thickness as shown and is subjected to a constant vertical upward shear force of $1500$ N acting at the shear centre.

a$)$ Determine and plot the flexural shear flow in the two flanges and the web.

b$)$ Locate the shear centre of the beam.

c$)$ Determine the location and magnitude of the maximum shear stress in the cross section.