Efficiency

Efficiency is a calculation of how efficient a machine is at utelising input energy into useful output energy. No machine can be 100% efficient, as energy is always lost through friction, heat, or sound, thus perpetual motion machines remain theoretical.

$$ \text{Efficiency (%)} = \frac{\text{work out}}{\text{work in}} \times 100 $$

Efficiency can also be calculated as

$$ \text{Efficiency (%)} = \frac{\text{output energy}}{\text{input energy}} \times 100 $$

Factors impacting efficiency

There are countless factors that impact efficiency, but common factors include:

• Deformation: Components or material stretching, warping, bending, such as a rope on a pulley system.
• Friction: Surfaces rubbing against each other, joints overly tight, poor lubrication.
• Heat: Energy lost through generation of heat.
• Sound: Energy lost through generation of sound.