PH 102 Lecture Notes - Lecture 5: Potential Energy, Electric Potential, Electric Field
Document Summary
The force between two point charges is e= kf qq. This force can do work by pushing the charges apart (if q1 and q2 have the same sign) or pulling them together (if q1 and q2 have opposite sign). There is a potential energy associated with these two charges. The change in potential energy is the negative of the work done during the displacement. Since the force is not constant, then we must calculate this work from the area under the force versus displacement curve, or by using integral calculus. Potential energy always depends on the choice of where the potential energy is assumed to be zero. For point charges, the convention is to assume that pe = Note that this equation is similar to the force formula except that pe varies inversely with r instead of r2. Also, pe is a scalar (it can be + or -), whereas force is a vector (magnitude and direction).
