When energy is wasted in machinery, which of the following is most commonly released?

In machinery, when energy is wasted, it is most commonly released as heat energy. This occurs due to friction between moving parts or inefficiencies in the machine's operation. As machinery operates, kinetic energy is often transformed into thermal energy due to these frictional forces, which results in an increase in temperature of the components involved.

Heat energy is a natural byproduct of many types of mechanical work, particularly in engines or machines where components rub against each other or where there are resistance forces like air resistance. This thermal energy is typically considered a form of wasted energy because it does not perform useful work and often needs to be dissipated or managed to prevent overheating.

Potential energy and chemical energy are not forms commonly associated with waste energy in machinery. Potential energy is related to an object's position and not typically considered in operational losses. Chemical energy might be released in chemical reactions but is not directly relevant to the operational inefficiencies of machinery that primarily involve mechanical energy conversions. Sound energy can be generated by machines, but it is usually a secondary consequence to the heat released and is not the primary form of wasted energy in most contexts. Thus, heat energy is recognized as the most common form of energy loss in machinery.