Three equal positive charges Q are each fixed at a corner of an equiliateral triangle of side length a. A negative charge -Q is placed at the midpoint of one of the sides.
(a) Draw a free body diagram for the negative charge. Find the magnitudes of the net force on the negative charge.
(b) Find the magnitudes of the net electric field at the triangle's center. Draw a diagram showing the individual electric field vectors due to each charge at the triangle's center.