Transferring Energy

Transferring Energy

Energy Forms and Transfers

• Energy can exist in several different forms, such as kinetic, potential, thermal, chemical, nuclear, electrical, and electromagnetic energy.
• Energy can be transferred from one form to another.
• No energy is lost when it is transferred, but it might move to less usable forms - this idea is known as the Law of Conservation of Energy.

Transfer Mechanisms

• Mechanical work: Energy can be transferred by forces, such as when you lift an object.
• Heating: Energy can be transferred by heating, such as when you heat water in a kettle.
• Radiation: Energy can be transferred via radiation, such as sunlight reaching the Earth.
• Electric work: Energy can be transferred by an electrical current, such as when a toaster uses electrical energy to produce thermal energy.

Efficiency

• Not all the energy transferred is used usefully. Some energy may always be wasted.
• The efficiency of a machine or process can be calculated as useful energy out / total energy in. The result can be expressed as a percentage or on a scale from 0 (no efficiency) to 1 (perfect efficiency).
• It is not possible to achieve 100% efficiency due to unavoidable energy losses, mainly as heat.

Power and Work

• Work is done when a force transfers energy. Work done, force, and distance are related by the equation: work done (J) = force (N) x distance (m).
• Power is the rate at which work is done or energy is transferred. Power, work, and time are related by the equation: power (W) = work done (J) / time (s).