Energy Stores

• What are the 8 energy stores?

  1. Kinetic
  2. Gravitational Potential
  3. Chemical
  4. Electrostatic
  5. Magnetic
  6. Elastic Potential
  7. Nuclear
  8. Thermal
• What is a description of a Kinetic energy store?

  Movement (E.G, a car/train)
• What is a description of a Gravitational Potential energy store?

  Anything above ground (E.G, plane/rock climber)
• What is a description of a chemical energy store?

  Stored energy released in chemical reactions (E.G, food/fuel/batteries)
• What is a description of a Electrostatic energy store?

  Electric charges moving together or apart (E.G, Lightning/electricity pylons)
• What is a description of a Magnetic energy store?

  Attraction of an object made of iron (E.G, Compass/fridge magnets)
• What is a description of a Elastic Potential energy store?

  Stretch or Squash (E.G, elastic band/spring)
• What is a description of a Nuclear energy store?

  Energy in the nucleus of an atom (E.G, Nuclear power plants/stars)
• What is a description of a Thermal energy store?

  Heat (E.G, Radiators/fires/hair dryer)
• State the law of conservation of energy :

  Energy cannot be created or destroyed, instead it is carried along a pathway from one energy store to another
• Power is the rate at which work is done
• Power = energy transferred/time
• power = work done/time
• 1 Watt = 1 joule per second
• How do u find Kinetic energy?

  kinetic energy = 1/2 mass x velocity2
• A car of mass 2450kg is travelling at 38m/s. calculate its kinetic energy?

  kinetic energy = 1/2 mass x velocity2

  kinetic energy = 1/2 2450 x 38 2

  Ek = 1768900J
• How do u find gravitational potential energy?

  Ep = mass x gravity x height
• An object of mass 47kg is slowly raised through 6.3. assuming gravity is 9.8N/kg. calculate the gravitational potential energy?

  Ep = mass x gravity x height

  Ep = 47 x 9.8 x 6.3

  Ep = 2901.78J
• How do we change Gravitational potential to Kinetic energy when calculating?


  Ep = m x g x h

  Ek = 0.5 x m x v ( 2 )

  Get rid of the squared

  = squared root of Ek/( 0.5 x m )

  = your answer
• Justin Bieber ( 60kg ) fell off a 108m cliff and landed in the sea. How fast was he going when he hit the water?

  step 1 :

  $Ep =$$mgh$

  = 60 x 9.8 x 108

  = 63504

  Step 2 :

  Ep -> Ek

  Ek = 63504J

  Step 3 :

  $Ek =$$0.5 *$$m *$$v2$

  63504 = 0.5 x 60 x v ( 2 )

  = 46,008J
• How do you find elastic potential energy?

  Ee = 1/2 x spring constant x extention
• A spring has a spring constant of 30n/m and is extended 0.2 . Calculate the Ee

  Ee = 0.5 x k x e ( 2 )

  = 0.5 x 30 x 0.2 ( 2 )

  = 0.6J