Describe examples of energy transfers in a closed system with no net change to total energy.

Closed-system examples are about conservation. In the Energy transfers in a system subtopic, energy may shift between kinetic, gravitational, elastic, chemical, or thermal stores, but the total energy of the closed system stays constant. A falling object, a pendulum, or a bouncing ball can be described by naming the stores before and after the transfer. The exam skill is to avoid saying energy is lost: if it is dissipated, it has moved to less useful thermal stores, not disappeared. In exam answers, include the named Energy transfers in a system context, state the relevant equation or energy principle, and finish with a sentence that explains what has physically changed in the system.