Electric Potential Between Two Points

[uchicago2012]

Homework Statement

The work done by an external force on an electron as it moves from point A to point B is 6.3 × 10-14 J. If it was started from rest and had 3 × 10-14 J of kinetic energy when it reached B, what is the potential difference VB-VA?

Homework Equations

V = k (q/r)
Delta V = delta U/q = -W/q

The Attempt at a Solution

We're told the work done on moving the electron from point A to point B and the charge of an electron is known so this should be straightforward but then we're given information about the kinetic energy. Does it have anything to do with the equation V = -W/q specifies that W is the work done by the electrostatic force to move some charge from point a to b and we are given the work done by just some unspecified external force? I'm confused.

 

[tiny-tim]

hi uchicago2012!

potential energy is defined as minus the work done (by a conservative force such as an electric field)

and work done = change in (mechanical) energy