The efficiency of a machine is the ratio between ___
Mechanical advantageVelocity ratio
Consider a machine which displaces an actual load W through a distance D, when effort E causes a displacement through distance d.
∴ Output of the machine
= Work done by the machine = W × D
∴ Input of the machine
= Work done on the machine = E× d
∴ Efficiency of the machine (η) = OutputInput
=W×DE×d=WE×Dd
or η=WE×Dd ...(i)
Now mechanical advantage (MA) of the system =LoadEffort=WE
Velocity ratio of the machine (VR)
=Distance moved by effortDistance moved by load=dD
By substituting these two values of MA and VR in Eq.(i), we get:
η=MA×1VR=MAVR
∴ Efficiency =Mechanical advantageVelocity ratio