The drawing shows two situations in which charges are placed on the x and y axes. They are all located at the same distance of 4.50 cm from the origin O. For each of the situations in the drawing, determine the magnitude of the net electric field at the origin. -5.0C +1.0 +2.0C -3.0C +4.0C -1.0C (a) E= i (b) E-i +6.0C (a) (b)