A flywheel is a rotating mechanical device that is used to store rotational energy and helps the engine in keeping the speed uniform

an electrical device which converts an alternating current into a direct one by allowing a current to flow through it in one direction only.

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911 in Leiden.

Angular momentum is equal to moment of inertia x angular velocity