The figure below shows four small spheres, each with a positive charge, at the corners of a square. The length of each side of the square is a. The sphere at top-right has a charge of q; the one at lower-left has a charge of 6.5q; the other two each have a charge of 6.0q. (Assume that the +x-axis is to the right and the +y-axis is up along the page.) 6.0q a a a 6.5q 6.09 (a) What is the magnitude of the force on the sphere with charge q? Express your answer in terms of ke, q, and a in symbolic form. e' F = (b) What is the direction of the force on the sphere with charge q? (Enter your answer in degrees counterclockwise from the +x-axis.) counterclockwise from the +x-axis