The coulomb force is given by k*q1*q2/r^2 so if there are two charges that have negative signs, then the force would be negative. Having said that, a "negative force" would then signal an attractive force since opposites attract. F=-dU/dx, so a negative force would result in a "positive potential" Does this mean a positive potential is attractive and a negative potential is repulsive? I'm not sure why there is a negative sign there. If this is the case, then why is the binding energy for an electron around the hydrogen atom -13.6 eV? The energy here is negatice, but the force is "binding" I'm confused, any thoughts would be appreciated.