5. Three Point charges are arranged as shown in the figure. How much work was required to move the middle charge in from infinitely far away with the other two charges already fixed in place? +10 nC +15 nC 20nC 5cm 10 cm 6. Point charges g1, g2, and gs are fixed at the vertices of an equilateral triangle whose sides are L long. a) Find an expression for the electrostatic potential energy of this system of charges. b) Find the value of the electrostatic potential energy of this system of charges for q; = 15uC, g2 = =30 uC, q3 = +60 uC, and L = 2.25 cm 7. The electric potential in a region of space is given by the expression V = 3x%y3 6xz2 + 10y2z*. a) Find the electric field in this region of space. b) Evaluate the magnitude of the field at the position = 71 4] + 10k