energy conservation

• Types of energy

  • Kinetic
  • Gravitational potential
  • Elastic
  • Thermal
  • Magnetic
  • Electrostatic
  • Nuclear
• Gravitational potential energy (GPE)


  Energy due to position
• GPE depends on the height of the objects and their mass
• The higher the object, the more GPE it has
• The greater the mass, the more GPE it has
• Kinetic energy (KE)


  Energy in moving objects
• Loss in GPE

  Gain in KE
• GPE = Mass x Gravitational field strength x Height
• KE = 1/2 x Mass x Velocity^2
• Energy transformations

  • Kinetic -> Gravitational potential
  • Kinetic -> Electrical
  • Chemical -> Thermal
  • Kinetic -> Sound
  • Electrical -> Sound
  • Chemical -> Electrical -> Sound
  • Elastic -> Kinetic
  • Electrical -> Thermal
  • Gravitational potential -> Kinetic
  • Electrical -> Kinetic
  • Electrical -> Kinetic
• Modes of energy transfer


  • Conduction
  • Convection
  • Radiation
• Conduction


  Energy transfer in solids by vibrating particles
• Convection


  Energy transfer in liquids and gases
• Radiation


  Energy transfer using infrared radiation
• Efficiency calculations can be represented using Sankey diagrams
• chemical energy


  in food, fuel and, batteries
• elastic energy


  in a stretched object
• thermal energy


  in a heated object
• electrical energy is the energy stored in the flow of electric charge in a circuit
• nuclear energy is the energy released by the splitting of atoms in a nuclear reactor.
• sankey diagram

  100% of energy in

  90% of energy output

  10% of energy wasted