Potential difference question.... 1. The problem statement, all variables and given/known data A proton (mass = 1.67 10-27 kg, charge = 1.60 10-19 C) moves from point A to point B under the influence of an electrostatic force only. At point A the proton moves with a speed of 60 km/s. At point B the speed of the proton is 80 km/s. Determine the potential difference Image . 2. Relevant equations Vb-Va = 0 3. The attempt at a solution a) +15v b) -15V c) -33V d) +33V e) -20V im stumped with this one....any help would be appreciated.