Two point charges are placed on the x-axis as follows: Charge q1 = +4.00 nC is located at x = 0.200 m and charge q2 = -5.40 nC is at x = +0.400 m. What is the magnitude of the net force exerted by these two charges on a third point charge q3 = -0.600 nC placed at the origin? What is the direction of the net force exerted by these two charges on a negative point charge q3 = -0.600 nC placed at the origin?