1. The problem statement, all variables and given/known data A proton is released from rest at the positive plate of a parallel plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the final speed of an electron released from rest at the negative plate? 2. Relevant equations KE= 1/2 mv^2 U= qV 3. The attempt at a solution I tried using conservation of energy, the left side is the proton and right side is the electron: KE1 + U1 = KE2 + U2 1/2mv^2 + qV = 1/2mv^2 + qV I do not understand what to plug in for V? I have tried searching for similar threads but I can't find a similar one. Any guidance would be appreciated, thank you.