Problem 3.372

At the moment $t=0$ an electron leaves one plate of a parallel-plate capacitor with a negligible velocity. An accelerating voltage, varying as $V=a t,$ where $a=100 \mathrm{~V} / \mathrm{s},$ is applied between the plates. The separation between the plates is $l=5.0 \mathrm{~cm} .$ What is the velocity of the electron at the moment it reaches the opposite plate?