A parallel-plate capacitor is charged to \(5000 \mathrm{~V}\). A proton is fired into the center of the capacitor at a speed of \(3.0 \times 10^{5} \mathrm{~m} / \mathrm{s}\), as shown in Figure P21.69. The proton is deflected while inside the capacitor, and the plates are long enough that the proton will hit one of them before emerging from the far side of the capacitor. What is the impact speed of the proton?

+++ ++++ + + + + + + + FIGURE P21.69