Book chapters Site Map Online Quizzimg About the Website chemistry Home Wiley Home

Fundamentals of chemical change

Kinetic and Potential Energy

The total energy of some isolated system remains the same. However, that energy can be present in different forms. For example, kinetic energy can become potential energy.

The simple pendulum is a good example of how potentia energy and kinetic energy interchange, even though the total energy always remains the same. The animation below shows that the pendulum has its maximum kinetic energy when it is at the bottom of its swing - this is when it is moving the fastest. When it reaches the "top" on either side (the point where it comes to an instantaneous stop and turns around), the pendulum has only potential energy. The total energy of the pendulum is the sum of the kinetic energy and the potential energy. The total energy is constant, but the proportions of kinetic and potential energies change.

Right click (Win) or hold the mouse (Mac) on the animation for a control menu.