Energy stores & systems

• What is the principle regarding energy as stated in the video?


  Energy is never created or destroyed; it is only transferred between different forms and objects.
• What are the different forms of energy mentioned in the video?

  • 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 related to?


  It is related to the heat energy trapped within an object and its temperature.
• What type of energy is associated with the movement of an object?

  Kinetic energy.
• What is gravitational potential energy?


  It is the energy that an object possesses because of its position in a gravitational field.
• What is elastic potential energy?


  It is the energy held in an already stretched spring.
• What type of energy is stored in chemical bonds?


  Chemical energy.
• What is magnetic energy?


  It is the energy that holds magnets to your fridge.
• What is electrostatic energy?


  It is the energy that can give you a shock when you touch your car.
• What is nuclear energy?


  It is the energy obtained from breaking atoms apart.
• How can energy be transferred between different forms?

  • Mechanically (e.g., stretching an elastic band)
  • Electrically (e.g., plugging into a socket)
  • By heating
  • By radiation (e.g., light or sound waves)
• What is meant by the term 'system' in physics?


  A system refers to a collection of matter being considered for energy transfer analysis.
• What happens to energy in an open system?


  Energy can be exchanged with the outside world, allowing the system to gain or lose energy.
• What is a closed system?


  A closed system is separate from the outside world, where neither matter nor energy can enter or leave.
• What is the overall change in energy in a closed system?


  The overall change is always zero, despite energy being transferred within the system.
• How does energy transfer occur in a kettle when it is turned on?

  1. Electrical energy flows to the heating element.
  2. Energy is transferred to the thermal energy store of the heating element.
  3. The heating element transfers energy to the water's thermal energy store.
• What is another way of saying 'energy transferred'?

  Work done.
• What are the two main types of work done?

  • Mechanical work done
  • Electrical work done
• What does mechanical work done involve?


  It involves using a force to move an object.
• What is an example of mechanical work done?


  Kicking a ball up in the air.
• What does electrical work involve?


  It involves current flowing and the energy required to overcome resistance in wires.
• How does friction do work in the example of a train crossing a broken bridge?


  • Friction between brakes and wheels slows the train down.
  • Energy in the wheel's kinetic energy stores is transferred to the thermal energy stores of the surroundings.
• What happens to the energy in the wheels of the train when it applies the brakes?

  Energy is transferred from the wheels' kinetic energy stores to the thermal energy stores of the surroundings.