(vA)y - (vB)y = r_dish*wx
r_dish = radius of antenna dish
=> wx = (15-9)/10 = 6/10 = 0.6 rad/s (counter-clock wise)
wz = (vB)y/r_arm
r_arm = length of arm = ...
The solution shows the step-by-step calculations to reaching the answer of the question posed on motion at a fixed point in the case of a rotating radar antenna.