$**4-8.$ The cable exerts a force of $P=6kN$ at the end of the $8-$m$-$long

crane boom. If $=30,$ determine the placement $x$ of the boom at $B$ so

that this force creates a maximum moment about point $O.$ What is this

moment?

$4-9.$ The cable exerts a force of $P=6kN$ at the end of the $8-m-$long crane

boom. If $x=10m,$ determine the angle $$ of the boom so that this force

creates a maximum moment about point $O.$ What is this moment?

Probs. $4-8/9$