1. The problem statement, all variables and given/known data A ping-pong ball, of mas3E-4kg is hanging from a light thread 1.0m long, between two vertical parallel plates 10cm (0.1m) apart. When the potential difference across the plates is 420 V, the ball comes to equilibrium 1cm (0.01m) to one side of it's original position. What is the mag. of elecric force deflecting the ball? kq/r^2 = E V/d = E 3. The attempt at a solution First I found the angle of the string through trig: asin(0.01/1) = 89 1. After that I equated the x component of tension to equate to gravity sin@T = mg T = mg/sin@ Then I solved for the y component cos@T = Fy cos@ (mg/sin@) = Fy I figured that this force would be the electric force, as Fnet = 0. This gave me the wrong answer 2. In my second attempt I solved for the charge of the ball Kq/r^2 = E Kq/r^2 = V/r q = Vr/K Then I plugged this value into F = qE, only to once again get a wrong answer. Im really unsure of what I'm doing wrong and a little help would be greatly appreciated.