How do energy changes occur in a pendulum?

Energy changes in a pendulum occur through the conversion between gravitational potential energy and kinetic energy.

When a pendulum is lifted to one side, it gains gravitational potential energy because it is raised against the force of gravity. This energy is at its maximum when the pendulum is at its highest point. As the pendulum is released and begins to swing downwards, this gravitational potential energy is converted into kinetic energy, which is the energy of motion.

At the lowest point of its swing, the pendulum's gravitational potential energy is at its minimum, while its kinetic energy is at its maximum. This is because the pendulum is moving at its fastest speed at this point. As the pendulum continues to swing upwards to the other side, the kinetic energy is converted back into gravitational potential energy. The pendulum slows down as it rises, reaching its highest point where the kinetic energy is at its minimum and gravitational potential energy is at its maximum again.

This process of energy conversion continues back and forth as the pendulum swings. In an ideal situation with no air resistance or friction, the pendulum would keep swinging indefinitely, with energy perfectly converting between kinetic and potential forms. However, in real-world scenarios, some energy is lost to air resistance and friction at the pivot point, causing the pendulum to eventually come to a stop.

Understanding these energy changes in a pendulum helps illustrate the principle of conservation of energy, which states that energy cannot be created or destroyed, only converted from one form to another. This principle is fundamental in physics and helps explain the behaviour of many different systems beyond just pendulums.