$5.$ Consider the beam and loading shown, with $\backslash (\backslash$boldsymbol$\{$P$\}=73\backslash$mathrm$\{$kN$\}\backslash ).$

$($a$)$ Determine the shearing stress at point $\backslash ($ a $\backslash ).$

$[8\mathrm{.}265$ MPa$]$

$($b$)$ Determine the largest shearing stress in section $\backslash ($ n$-$n $\backslash ).$

$[9\mathrm{.}092$ MPa$]$