A ring of charge with radius R = 3.5 m is centered on the origin in the x-y plane. A positive point charge is located at the following coordinates:
x = -6.8 m
y = 5.0 m
z = -18.5 m
The point charge and the total charge on the ring are the same, Q = +48 µC.
Find the net electric field along the z-axis at z = 9.0 m.