Problem $3$

Another bracket in the UHart machine shop has dimensions $x_{AB}=160mm,y_{BC}=140mm,$ and $z_{AO}=300mm$ with applied force magnitudes of $F_{Ay}=20N,F_{Az}=12\mathrm{.}5N,F_{Bx}=40N,F_{Bz}=12\mathrm{.}5N,F_{Cx}=40N,$ and $F_{Cy}=20N.$

Determine:

a$.)$ The resultant moment in terms of i$,$ j$,$ and k unit vectors

b$.)$ The moment about line OA