The figure below shows forces acting at various points on a metal cylinder. The angles $=46,=33,=21.$ The length $l=4\mathrm{.}2m.$ Find the net torque $($in $N*m)$ on the cylinder about the following axes.

$($i$)$

$($a$)$ an axis through $O$ perpendicular to the page magnitude $q,N*m$ direction $---$Select$---$

$($b$)$ an axis through $C$ perpendicular to the page magnitude $N*m$ direction

$---$Select$---$