topic 1 energy

• Closed System


  A system that experiences no net change in its total energy when energy transfers occur within it
• Conservation of Energy


  The law that energy can be transferred, stored or dissipated but never created or destroyed
• Efficiency


  The ratio of useful output energy transfer to total energy input
• Elastic Potential Energy


  The store of energy that stretched or compressed objects experience. It is directly proportional to the stiffness constant and to the square of the extension or compression
• Fossil Fuels


  • Coal
  • Oil
  • Gas
• Gravitational Potential Energy


  The store of energy that all raised matter has. It is directly proportional to the mass of the object, the distance that it is risen and the gravitational field strength at that point
• Joule


  The unit used for energy. Equal to the work done when a force of one Newton acts over a distance of one metre
• Kinetic Energy


  The store of energy that all moving matter has. It is directly proportional to the object's mass and to the square of its velocity
• Power


  The rate at which energy is transferred, or at which work is done
• Renewable Energy Resource


  An energy resource that can be replenished whilst it is being used
• Specific Heat Capacity


  The amount of energy required to raise the temperature of 1kg of a substance by 1°C
• Spring Constant


  A measure of a spring's stiffness. The greater the value, the greater the force required to stretch or compress the spring by a given distance
• System


  A single, or group, of objects
• Thermal Conductivity


  The higher this value is for a given material, the higher the material's rate of energy transfer via conduction will be
• Waste Energy


  Energy that isn't usefully used for the purpose of the system
• Watt


  A unit of power. One Watt is equivalent to one joule of work being done in one second
• Work Done


  The energy transferred when a force acts over a distance