What would the separation between two identical objects, one carrying 2 C
of positive charge and the other
2 C
of negative charge, have to be if the electrical force on each was precisely
9 N?

From negative to negative

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling

Pe = 1/2k(x)^2  and .05n/m = .05x10^-9m = x