$5\mathrm{.}111$ The crane's cable $CD$ is attached to a stationary object a

D$.$ The crane is supported by the bearings $E$ and $F$ and the horizontal cable $AB.$ The tension in cable $AB$ is $8$ kN $.$ Determine the tension in the cable $CD.$

Strategy: Since the reactions exerted on the crane by the bearings do not exert moments about the $z$ axis, the sum of the moments about the zaxis due to the forces exerted on the crane by the cables $AB$ and $CD$ equals zero.