What physical principle is demonstrated when a pendulum swings from a height, slows down, and eventually stalls?

The correct answer revolves around the law of conservation of energy. When a pendulum is raised to a certain height, it possesses gravitational potential energy due to its elevated position. As it swings downwards, this potential energy is converted into kinetic energy, causing the pendulum to accelerate and swing faster. However, as the pendulum reaches its lowest point and starts to ascend again, it slows down because its kinetic energy is transformed back into potential energy.

Eventually, when the pendulum reaches its highest point on the other side, it comes to a temporary stop before swinging back down. This demonstrates how energy is conserved within the system as it transitions between kinetic and potential forms. The total amount of mechanical energy (the sum of potential and kinetic energy) remains constant, assuming no external forces like air resistance or friction are acting significantly on it.

This principle highlights the dynamic relationship between potential and kinetic energy in systems influenced by gravity, illustrating the fundamental concept of energy conservation.