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 51000 m/s . What will be the final speed of an electron released from rest at the negative plate? 2. Relevant equations 3. The attempt at a solution I'm struggling as to what equations to use, I've tried using KE, assuming that the KE in the system is the same for both the Proton and the Electron, but that didn't work. I've also tried to find the magnitude of the electric field and work back to a kinematic equation, I'm so stuck . I could really just use some guidance as to where to start.