⇒ Here, an electric motor is being used to lift a weight

⇒ Electrical energy is being transferred to gravitational potential energy, plus heat and sound energy)

⇒ Below, a sankey diagram shows how 100J of electrical energy are transferred to the other types of energy (with the majority being transferred to heat and sound energy, and only 30J being transferred to usesful gravitational potential energy)

⇒ A Sankey diagram is a specific flow diagram in which the width of the arrows is proportional to the quantity of the flow. Here they are used to show how energy is transferred in various processes

⇒ The efficiency of a machine is defined as follows:

⇒ Also see our notes on:

• Work
• Calculating Energy
• The Principle of Conservation of Energy
• Power