Mechanical efficiency 420302 223159911 2008-07-02T20:48:39Z Rios sk 4274638 + sk In [[physics]], '''mechanical efficiency''' is the effectiveness of a machine and is defined as :<math>\mbox{Efficiency} = \frac{\mathrm{Mechanical Advantage}}{\mathrm{Velocity Ratio}}</math> To show the effectiveness of a machine one must compare its work input to its work output. Efficiency is often indicated by a [[percentage]], the efficiency of an [[ideal machine]] is 100%. Due to the fact that energy cannot emerge from nothing and the [[Second law of thermodynamics]] which states that the quality of energy will always decrease (transforming from mechanical energy to [[thermal energy]]) the mechanical efficiency of any machine will always be less than 100%. Additionally, there will always be some friction to hinder the machine's performance. ==See also== *[[Thermal efficiency]] *[[Electrical efficiency]] *[[Internal combustion engine]] *[[Electric motor]] [[Category:Mechanical engineering]] {{classicalmechanics-stub}} [[he:נצילות מכנית]] [[sk:Mechanická účinnosť]]