Energy stores, transferring energy & work done

• What is the key principle governing energy transformations?

  • Energy is never created or destroyed
  • It's only ever transferred between different forms and objects
• Name the different forms that energy can take.

  • Thermal or internal energy
  • Kinetic energy
  • Gravitational potential energy
  • Elastic potential energy
  • Chemical energy
  • Magnetic energy
  • Electrostatic energy
  • Nuclear energy
• What is thermal or internal energy?

  The heat energy trapped within an object, related to its temperature.
• What is kinetic energy?

  The energy associated with the movement or motion of an object.
• What is gravitational potential energy?

  The energy an object possesses due to its position in a gravitational field.
• What is chemical energy?

  Energy stored in chemical bonds.
• What is magnetic energy?

  The energy that holds magnets together.
• What is electrostatic energy?

  Energy associated with static electricity.
• What is nuclear energy?

  The energy produced by breaking atoms apart.
• How can energy be transferred between different stores?

  • Mechanically: physically moving objects, like stretching an elastic band
  • Electrically: plugging something into a socket
  • By heating: direct transfer of thermal energy
  • By radiation: through light or sound waves
• What is a system in physics?

  • A system is a collection of matter being considered.
  • It's a term used to describe the specific group of objects or materials being analyzed.
• What characterizes an open system?

  • Matter can exchange energy with the outside world
  • Can lose or gain energy as it interacts with the surroundings
• How does a closed system differ from an open system?

  • A closed system is separate from the outside world
  • Neither matter nor energy can enter or leave
  • The overall energy change within the system is always zero
• What are the two main types of work done?

  Mechanical and electrical work done.
• What is mechanical work done?

  The work done when a force moves an object.
• What is electrical work done?

  The work done when current flows in a circuit.
• What happens to the energy in the wheel when the train brakes are applied?

  The kinetic energy is transferred to thermal energy of the surroundings as heat.
• What does friction do in terms of energy transfer when a train brakes?

  Friction does work by converting kinetic energy into thermal energy.
• How does the energy transformation work in a boiling kettle?

  1. Electrical energy flows from the socket to the heating element.
  2. Electrical energy is transferred electrically to thermal energy in the heating element.
  3. The heating element transfers thermal energy to the water.
  4. The water's thermal energy store increases, eventually boiling the kettle.