Why does earth and electrons rotate? From where do they derive energy to rotate? When will they stop rotating?

rotation of a particle has nothing to do with the energy.... when a particle travels in the space linearly, theres no force acting on it hence velocity remains constant... but if a force acts then velocity changes..be it its direction or magnitude... for electrons.. nucleus applies an electrostatic force of attraction .. on the electron.. as the force is perpendicular to the direction of velocity .. magnitude of velocity is unaffected because the component of force in the direction of velocity is zero but the direction of velocity changes such that force is always perpendicular to the velocity..which results in circular motion