Two small plastic balls hang from threads of negligible mass. Each ball has a mass of 0.14 g and a charge of magnitude q. The balls are attracted to each other, and the threads attached to the balls make an angle of 20.0 degrees with the vertical. The threads are separated by a distance of 2.05 cm. Find (a) the magnitude of the electric force acting on each ball, (b) the tension in each of the threads, and (c) the magnitude of the charge on the balls.