Final answer:
Swinging on swings is an example of mechanical energy, encompassing both kinetic and potential energy, changing forms as the swing moves but remaining constant in total.
Step-by-step explanation:
Swinging on the swings involves a type of energy known as mechanical energy, which includes both kinetic energy and potential energy. When a child swings upward, potential energy increases due to gaining height, while kinetic energy decreases, since the swing is decelerating. Conversely, as the child swings downward, kinetic energy increases because the swing is accelerating, and potential energy decreases as the height is lost. This exchange of energies is perfectly showcased by the conservation of mechanical energy, indicating that in a closed system without external forces, the total mechanical energy remains constant. The oscillation of the swing, similar to a pendulum, illustrates how energy is transferred between potential and kinetic forms, maintaining the overall mechanical energy of the system.