Two point charges are located on the y axis as follows: charge q1 = -1.50nC at y1 = -0.550m , and charge q2 = 4.10nC at the origin (y = 0). What is the magnitude of the net force exerted by these two charges on a third charge q3 = 7.50nC located at y3 = 0.350m ? and what is the direction of the net force?