$*4-20.$ The tower crane is used to hoist the $2-$Mg load upward at constant velocity. The

$1\mathrm{.}5-Mg$ jib BD$,0\mathrm{.}5-Mg$ jib BC$,$ and $6-Mg$ counterweight C have centers of mass at G$1,$ G$2,$

and G$3,$ respectively. Determine the resultant moment produced by the load and the

weight of the tower crane jibs about point A and about point B $.$ The tower crane is used

to hoist the $2-$Mg load upward at constant velocity. The $1\mathrm{.}5-Mg$ jib BD$,0\mathrm{.}5-Mg$ jib BC$,$ and

$6-Mg$ counterweight C have centers of mass at G$1,$ G$2,$ and G$3,$ respectively. Determine

the resultant moment produced by the load and the weights of the tower crane jibs about

point A and about point $B.$