How is the efficiency of a machine defined?

The efficiency of a machine is defined as the ratio of useful work output to total work input. This means that efficiency measures how effectively a machine converts the input energy or work into useful output. A higher efficiency indicates that a larger proportion of the input energy is being transformed into useful work, while a lower efficiency signifies that more energy is being lost (typically as heat or friction) rather than being used for the intended purpose. Understanding efficiency is crucial in fields like engineering and manufacturing, as it directly influences performance, cost-effectiveness, and energy consumption in mechanical systems.

The other options presented do not accurately capture the concept of efficiency. The first choice refers to physical weight and power output, which are not factors in defining efficiency. The third choice discusses operating speed rather than the effective transformation of energy. The fourth option mentions energy consumption versus energy wasted, which touches on related concepts but does not provide the specific definition of efficiency as a ratio of useful output to input.