Two uncharged, conducting spheres are separated by a distance d. When charge −Q is moved from sphere A to sphere B, the Coulomb force between them has magnitude F0.

(a)Is the Coulomb force attractive or repulsive?

attractive repulsive

(b) If an additional charge −Q is moved from A to B, what is the ratio of the new Coulomb force to the original Coulomb force,(c) If sphere B is neutralized so it has no net charge, what is the ratio of the new to the original Coulomb force,