As shown in the figure, a ball with a mass of 1.020 g and positive charge of q=44.0 C is suspended on a string of negligible mass in a uniform electric field. 9 48 mg Uniform E-field We observe that the ball hangs at an angle of 0=19.0 from the vertical. What is the magnitude of the electric field? Draw a free body diagram for the ball. Since the ball is at rest the vector sum of all the forces, including the tension in the string, must be zero.