Final answer:
In vehicles, a flywheel is the component that transmits rotational energy to its respective gearboxes. It stores rotational kinetic energy and converts it into the necessary energy for acceleration or to overcome friction.
Step-by-step explanation:
In vehicles, such as buses and cars, the component that transmits rotational energy to its respective gearboxes is a flywheel. A flywheel is a mechanical device that stores rotational energy and releases it when needed. When the vehicle goes down a hill or stops, the flywheel's rotational kinetic energy converts into the necessary energy for acceleration or to overcome friction.