$14\mathrm{.}1$ Calculate the section modulus for:

$($a$)$ a $6-$in$.-$by$-10-$in$.($S$4$S$)$ timber cross section, with respect to the strong axis $($check with Appendix E$)$

$($b$)$ a pipe cross section having an inner diameter of $100$ mm and an outer diameter of $114$ mm

$($c$)$ the cross section of Example $14\mathrm{.}16,$ with respect to the weak axis $($a$)$ beam cross section