<Dl> <Dd> P in = P out + P fric (\ displaystyle P_ (\ text (in)) = P_ (\ text (out)) + P_ (\ text (fric)) \,) </Dd> </Dl> <Dd> P in = P out + P fric (\ displaystyle P_ (\ text (in)) = P_ (\ text (out)) + P_ (\ text (fric)) \,) </Dd> <P> The mechanical efficiency η (\ displaystyle \ eta \,) of a machine (where 0 <η <1 (\ displaystyle 0 <\ eta \ <1)) is defined as the ratio of power out to the power in, and is a measure of the frictional energy losses </P> <Dl> <Dd> η ≡ P out P in (\ displaystyle \ eta \ equiv (P_ (\ text (out)) \ over P_ (\ text (in))) \,) </Dd> <Dd> P out = η P in (\ displaystyle P_ (\ text (out)) = \ eta P_ (\ text (in)) \,) </Dd> </Dl>

Name a machine which is used to multiply force