Energy

• 8 energy stores

  . Kinetic

  . Gravitational potential

  . Chemical

  . Thermal

  . Nuclear

  . Electrostatic

  . Magnetic

  . Elastic potential
• 4 energy transfers

  . Work done by a force

  . Electrical current

  . Heating

  . Radiation
• 3 ways heat can be transferred

  . Conduction

  . Convection

  . Radiation
• Law of conservation of energy:

  Energy cannot be created or destroyed only transferred from one store to another
• What is a closed system?

  A system where energy is not transferred to surroundings
• Most wasted energy ends up dissipated as heat in the surroundings
• Energy is measured in joules (J)
• Kinetic energy = 0.5 × mass × velocity ²
• Unit for mass is kg
• Units for speed/velocity are metres per second (m/s)
• Gravitational potential energy = mass × Gravitational field strength × height
• Gravitational field strength = newton's per kg (N/kg)
• Height is measured in metres (m)
• Work done = force × distance
• Work done is measured in joules
• Force is measured in newton's (N)
• Distance is measured in metres (m)
• Power = energy ÷ time
• Power is measured in Watts
• Time is measured in seconds