Two equal positive charges of magnitude q1 = q2 = 5.5 nC are on the y axis at y1 = +3 cm and y2 = -3 cm.
(a) What is the magnitude and direction of the electric field on the x axis at x = 2 cm?
(b) What is the force exerted on a third charge q0 = 4 nC when it is placed on the x axis at x = 2 cm?