Solve the all parts of following problem given below:

Problem: An electron is accelerated inside a parallel plate capacitor. The electron leaves the negative plate with a negligible initial velocity and then after the acceleration it hits the positive plate with a final velocity B. The distance between the plates is 14.4 cm, and the voltage difference is 120 kV.

Part I: Determine the final velocity B of the electron using classical mechanics. (The rest mass of the electron is 9.11 x 10^-31 kg, the rest energy of the electron is 511 keV.)

Part II: What is the final velocity B of the electron if you use relativistic mechanics?

Show each step and detailed calculation for help. Thanks.