Sketch a thin$-$walled symmetrical channel section with flange width $4$ cm $,$ web height $8$ cm and wall thickness $2$ mm $.$ Derive and obtain an expression for the maximum shear stress in the section when subject to a vertical shearing load. If the maximum shear stress $\backslash (=300\backslash$mathrm$\{$MPa$\}\backslash ),$ find the magnitude of the vertical shearing load. Plot the shear flow variation. Determine the shear centre position and mark the same on the crosssection. Verify if the force of the shear flow equals the applied shear.