An electron is released from rest at the negative plate of a parallel plate capacitor and accelerates to the
positive plate (see the drawing). The plates are separated by a distance of 1.2 $\mathrm{cm}$ , and the electric field within the capacitor has a magnitude of 2.1 $\times 10^{6} \mathrm{V} / \mathrm{m}$ . What is the kinetic energy of the electron just as it reaches the positive plate?