Q$\mathrm{.}4($b$)$ A channel section is being used for a cantilever beam that supports a load $P$ at the free end. Centerline dimensions for the channel are shown in Figure. All metal in the channel section is $12$ mm thick. Assume that all of the section is effective in resisting flexural stresses and that only the web resists vertical shearing stresses, locate the shear center $(e)$ of the section with respect to the center of the web.