determine the force about x axis y axis and z axis and AB ax

determine the force about x axis, y axis, and z axis, and AB axis show all work and please explain all steps

solution

moment about y axis = (50i - 40j + 20k) (4j)

= -160 lbf.ft

moment about z axis = (50i - 40j + 20k) (2k)

= 40 lbf.ft

moment about AB axis = (50i - 40j + 20k) ( 4i + 3j )

= 80 lbf.ft