4. A uniformly-charged bar has length 2:51 and total charge Q. On the perpendicular bisector at a distance 3a from the bar: (10 points) (a) determine the electric eld. 3a (10 points) (b) determine the voltage. (10 points) (c) If the middle half of the bar (from u/2 to (1/2) is removed, re-evaluate your answers to (a) and (b) above. 10-P0i11t Bonus: With the middle half removed, determine the force of repulsion between the remaining pieces. +61