QUESTION $3[10$ MARKS$]$

The system shown in Figure $3$ is subjected to force, F$.$

a$)$ Determine the moment $($as Cartesian vector$)$ of this force about point $B.$

$[5$ marks$]$

b$)$ Find the coordinate direction angles of the moment about point $B.[1\mathrm{.}5$ marks$]$

c$)$ Determine the magnitude of the moment of this force about $BC.$

$[2$ marks$]$

d$)$ Express your answer in $($c$)$ as Cartesian vector.

$[1\mathrm{.}5$ marks$]$

Figure $3$: A system exerted by one force