1. The problem statement, all variables and given/known data Two identical parallel metal plates are separated by 8 mm. A voltage of 170V is applied across them. A proton moves in the same direction of electric field between the two plates through a distance of 3mm. If the initial speed of the proton is 1.5 x 105 m/s, what is the final kinetic energy of the proton? 2. Relevant equations ΔV = E ΔX KE = 0.5mv2 ΔPE = -qEΔX 3. The attempt at a solution Since the proton moves in the same direction of the electric field, the proton gains kinetic energy but lose potential energy. I was thinking that the final kinetic energy: KEfinal = KEinitial + ΔPE I have found that ΔPE = -1.02 x 10-17 J Is this the correct way of solving this problem? Please correct me if I am wrong.