The rotational energy typically comes from an engine or electric motor.

They are simply derived from the term for the rotational energy.

More than that: its rotational energy has been "compressed," too.

As an example, let us calculate the rotational kinetic energy of the Earth.

The rotational energy means that less energy is available for translation of the ball.

When considering energies, possible rotational energy before and/or after a collision may also play a role.

It had abundant rotational energy and was nowhere near depletion.

Note this is only a tiny fraction of the total rotational energy of the Earth.

One way is to interact with the rotational energy of the molecules as they rotate in their environment.

A second consideration is the rotational energy stored in the wheels.