1. Skillfulness in avoiding wasted time and effort.
2. The ratio of the output to the input of any system.
Output of a machine (work done by the machine) divided by the input (work put into the machine), usually expressed as a percentage. Because of losses caused by friction, efficiency is always less than 100%, although it can approach this for electrical machines with no moving parts (such as a transformer).
Since the mechanical advantage, or force ratio, is the ratio of the load (the output force) to the effort (the input force), and the velocity ratio is the distance moved by the effort divided by the distance moved by the load, for certain machines the efficiency can also be defined as the mechanical advantage divided by the velocity ratio.
Competency or capability of performance. Producing desired change with little waste of money, resources, time, etc. + prikaži više