A $\backslash (13-\backslash$mathrm$\{$kN$\}\backslash )$ force is applied as shown to the $\backslash (60-\backslash$mathrm$\{$mm$\}\backslash )$ diameter cast$-$iron post ABD $.$

At point H$,$ determine;

a$)(\backslash \%5)$ the principal stresses and principal planes,

b$)(\backslash \%5)$ the maximum shearing stress,

c$)(\backslash \%5)$ the principal stresses and principal planes by using Mohr's circle,

d$)(\backslash \%5)$ the maximum shearing stress by using Mohr's circle.