Question $2(25$ points$)$

If $F_1=100i-120j+75k,1b_f$ and $F_2=-200i-250j+100k,$ Ib $b_f,$ determine:

A$)$ The angle between $F_1$ and $F_2.$

B$)$ The resultant force vector, from these two vectors, in Cartesian vector format, in units of Newtons $($N$).$

C$)$ The moment created by the resultant force vector around point $O,$ in units of Newton meters $($ N $m$