Examples

• Objects accelerated by constant force

  • Work is done by a force on an object.
  • This work is converted to the object's kinetic store.
• Boiling water in an electric kettle

  • Energy transfers from the electrical store of the mains power supply to the thermal store of the water.
• A vehicle slowing down

  • To begin with, the vehicle's energy is in the kinetic store.
  • The brakes do work slowing the car down. During this process, energy is dissipated (lost) through heat and sound.
• An object projected upwards

  • The object's energy is initially in the kinetic store as it moves upwards.
  • The object's energy is slowly transferred from the kinetic store to the gravitational potential store as it slows down and climbs higher.
  • Once the object reaches its highest point, all of its energy is in the gravitational potential store.
  • As the object falls again, energy transfers from the gravitational potential store to the kinetic store.
• A moving object hitting an obstacle

  • The object's energy is in the kinetic store to begin with because it is moving.
  • When the object collides with the obstacle, energy is converted to:
  • The kinetic store of the obstacle (making it move),
  • The thermal store of the object and the obstacle (the particles in the object and the obstacle vibrate more).
  • Some energy remains in the object's kinetic store as it moves away after the collision.