A small plastic ball of mass 7.81 x 10^-3 kg and charge +0.174 uC is suspended from an insulating thread and hangs between the plates of a capacitor (see the drawing). The ball is in equilibrium, with the thread making an angle of 30.0 with respect to the vertical. the area of each plate is 0.01670 m^2. what is the magnitude of the charge on each plate.