An electron is shot upward directly perpendicular to the lower plate of a parallel plate capacitor. Its initial velocity is 3.0 x 104 m/s. What must be the potential of the upper plate if the electron is to stop just before reaching it? The lower plate is at a potential of 0 V. How does this answer change if the electron is shot at an angle of 45° to the plate? Hint: Compare this to projectile motion.