How is the efficiency of a machine defined?

The efficiency of a machine is defined as the ratio of useful energy output to the total energy input. It is expressed as a fraction or a percentage, showcasing how much of the input energy is converted into useful work or energy. The formula for calculating efficiency is:

[ \text{Efficiency} = \frac{\text{Useful Energy Output}}{\text{Total Energy Input}} ]

This definition highlights the importance of both input and output energies, indicating how effectively the machine converts input energy into desired work. A high efficiency means that a larger proportion of the input energy is being utilized effectively, while a lower efficiency suggests that more energy is wasted or unutilized.

Understanding this definition allows for evaluating a machine's performance, which is essential in physics and engineering when designing and analyzing systems.