If you let go two oposite charges from distance D they will start to attract and if they can pass thru each other when they meet they will distant them selfs until they reach -D distance. They they will start geting back until they get to the initial distance D. This domain from D to -D via the zero or equilibrium point, is the INTERACTIVE INTERIOR. If the charges were same by sign they would repeal and get more and more distant. If they could pass the infinity point they would change the sign of their equilibrium distances and continue to reduce the absolute distance between them until they reach -D distance. Then they will go backwards until they get to the initial D distance. The domain from D to -D via the infinity point or where the charges repeal is INTERACTIVE EXTERIOR. By the way the forces and the distances are related, based on the rules of lever, this way F1 * D1 = F2 * D2. This equation breaks down to the system of equations: dF1/D2=dF2/D1<0 and dD1/F2=dD2/F1>0 because of preserving the formality and because the force makes displacement in same direction of the actual force. Now the point of the Nuclear energy or Nuclear force, since they are proportional, is to shift repealing charges from the I. Exterior into the I. Interior, making them this way atracting, or vice versa for the oposite charges. How close?