energy stores and systems

• 8 energy stores:

  • thermal energy
  • kinetic energy
  • gravitational potential energy
  • elastic potential energy
  • chemical energy
  • magnetic energy
  • electrostatic energy
• • a system is an object or group of objects
• • energy is transferred mechanically/doing work, electrically, heating, radiation
• • when a system changes, energy is transferred
  • closed systems are systems where neither matter or energy can leave
  • total energy is a closed system does not change
• transferring through heating (kettle) :

  • energy transferred electrically to thermal energy store of kettle's heating element
  • energy from heating element transfers enery by heating to water's thermal energy store
• energy transferred by doing work (object projected upwards):

  • force exerted by throwing ball upwards does work
  • energy transfeer from chemical store of arm to kinetic energy store of ball and arm
• energy transferred by doing work (object accelerated by gravity) :

  • ball dropped from height is accelerated by gravity
  • gravitational force does work
  • energy transferred from ball's gravitational potential energy store to kinetic energy store
• energy transferred by doing work (moving object hitting obstacle) :

  • normal contact between car and object does work
  • energy transferred from car's kinetic enegy store to other energy stores e.g sound waves, elastic potential and thermal stores of car body