A body with points $A,B$ and $C$ as indicated below has a force, $\frac{?}{\text{b}\text{a}\text{r}}(F)=(\frac{30}{b}ar(i)+\frac{60}{b}ar(j)-\frac{90}{b}ar(k))N$ The moment of the force $\frac{?}{\text{b}\text{a}\text{r}}(F)$ about point $D$ :

has the same magnitude and direction as the moment about point $A$

has the same magnitude and opposite direction as the moment about point $A$

cannot be related to the moment about point $A$ in any way

Calculate the moment of the force $\frac{?}{\text{b}\text{a}\text{r}}(F)$ about line $AC,M_{AC}.$

$M_{AC}=(\frac{,}{b}ar(i)+\frac{,}{b}ar(j)+\frac{,}{b}ar(k))Nm$

applied at point $B.$

$A=(3,5,-1)m$

$B=(-9,-3,-10)m$

$C=(-2,-4,5)m$

Point $D$ is on the same line as $AB.$ Point $B$ is in the middle of points A and $D.$

a$)$

Calculate the moment of the force $\frac{?}{\text{b}\text{a}\text{r}}(F)$ about point $A,M_A.$

$\{$:$M_A=1,(\frac{?}{\text{b}\text{a}\text{r}}(i))+,(\frac{?}{\text{b}\text{a}\text{r}}(j))+,(\frac{?}{\text{b}\text{a}\text{r}}(k)))Nm$