posted by Trevor .
A small plastic ball with a mass of 6.50x10^-3 kg and with a charge of +0.150x10^-6 C is suspended from an insulating thread and hangs between the plates of a capacitor. The ball is in equilibrium, whit the tread making an angle of 30 degrees with respect to the vertical. The area of each plate is 0.0150 m^2. What is the magnitude of the charge of each plate?