A 1.00 g cork ball with charge 2.00 uC is suspended vertically on a 5.00 m long, light string in the presence of a uniform, downward-directed electric field of magnitude E = 1.00 x 10^5 N/C. If the ball is displaced slightly from the vertical, it oscillates like a simple pendulum.
a) Determine the period of this oscillation.
Also, can you tell me if you think gravity should be included in this calculation?