Four electric charges are arranged as shown. Each charge is placed a distance d = 3.0 cm from the origin, and the values of the charges are q1 = 1.5 µC, q2 = 3.0 µC, q3 = 4.5 µC, and
q4 = 6.0 µC.

(a) Determine the magnitude of the electric field E at the origin.
(b) Determine the direction of the electric field E at the origin. Express your answer as an angle θ, measured counterclockwise from the +x direction.
Now an electron of mass m = 9.11×10-31 kg and charge q = −1.60 ×10-19 C is placed at the origin and released from rest.
(c) Calculate the magnitude the initial acceleration of the electron.
(d) Determine the direction of the initial acceleration of the electron.