In the figure below, each charged particle is located at one of the four vertices of a square with side length = a. In the figure, A = E = a Aq 0 a Bq F = 9 Cq (a) What is the expression for the magnitude of the electric field in the upper right corner of the square (at the location of q)? (Use the following as necessary: q, a, and k.) 3, B = 4, and C = 7, and q > 0. Give the direction angle (in degrees counterclockwise from the +x-axis) of the electric field at this location. (counterclockwise from the +x-axis) (b) Determine the expression for the total electric force exerted on the charge q. (Enter the magnitude. Use the following as necessary: q, a, and k.) Give the direction angle (in degrees counterclockwise from the +x-axis) of the electric force on q. O (counterclockwise from the +x-axis)