What does efficiency measure in a machine?

Efficiency in a machine is a measure of how well it converts input energy into useful output work relative to the total energy or work put into the system. When we talk about efficiency, we often refer to how effectively a machine performs its intended task while minimizing waste, whether that be energy, time, or materials.

The correct answer highlights that efficiency reflects the machine's capability to accomplish work with minimal resources, aligning with the definition of efficiency in physics and engineering. It essentially indicates how much input energy is transformed into useful output versus how much is lost to factors like friction and heat during operation.

Measuring efficiency is important in various contexts, as it can help in optimizing machines for better performance and lower costs. This understanding is crucial for engineers and scientists looking to design or improve machines for various applications.