Work and energy

• force= spring constant x extension
• Car safety features


  • Airbags
  • Crumple zones
• Crumple zones and airbags

  • They change in a collision
  • They allow the work to be done over a longer distance
  • This reduces the force on the passengers
• The longer the distance the work is done over, the smaller the force on the passengers will be
• Car efficiency to reduce green house gases

  Less energy being wasted
• Efficiency features


  • Start stop
  • Lighter materials to reduce the mass of the car
  • More streamlined shape to reduce friction
  • Correctly inflated tyres to reduce work done by friction
• The total energy at the start must equal the total energy at the end of the action unless energy is lost by heat
• Potential energy


  Gravitational potential energy = mass & height
• Kinetic Energy


  Kinetic Energy = 1/2 mass velocity^2
• Some energy is lost due to the work done by Friction
• Work = Force x distance