Descartes - Discourse ON the Method(545h55)

Definitions and Concepts for AQA Physics GCSE Topic 1: Energy

Closed System

  • Closed System: A system that experiences no net change in its total energy when energy transfers occur within it.

Conservation of Energy

  • Conservation of Energy: The law that energy can be transferred, stored or dissipated but never created or destroyed.

Efficiency

  • Efficiency: The ratio of useful output energy transfer to total energy input.

Types of Energy

Elastic Potential Energy

  • Elastic Potential Energy: The store of energy that stretched or compressed objects experience.

    • Directly proportional to the stiffness constant and to the square of the extension or compression.

Fossil Fuels

  • Fossil Fuels: Coal, oil, and gas that are used as energy sources.

Gravitational Potential Energy

  • Gravitational Potential Energy: The store of energy that all raised matter possesses.

    • Directly proportional to:

      • Mass of the object

      • Distance risen

      • Gravitational field strength at that point.

Joule

  • Joule: The unit of energy, defined as the work done when a force of one Newton acts over a distance of one metre.

Kinetic Energy

  • Kinetic Energy: The store of energy possessed by moving matter.

    • Directly proportional to:

      • Mass of the object

      • Square of its velocity.

Power

  • Power: The rate at which energy is transferred or at which work is done.

Renewable Energy Resource

  • Renewable Energy Resource: An energy resource that can be replenished while being used.

Specific Heat Capacity

  • Specific Heat Capacity: The amount of energy required to raise the temperature of 1 kg of a substance by 1°C.

Spring Constant

  • Spring Constant: A measure of a spring’s stiffness; a greater value indicates a greater force required to stretch or compress the spring by a given distance.

General Concepts

System

  • System: A single or group of objects.

Thermal Conductivity

  • Thermal Conductivity: The higher this value for a given material, the higher the material’s rate of energy transfer via conduction.

Waste Energy

  • Waste Energy: Energy that isn’t usefully used for the purpose of the system.

Watt

  • Watt: A unit of power, defined as one joule of work being done in one second.

Work Done

  • Work Done: The energy transferred when a force acts over a distance.