P1.1 - Energy Stores and Systems

• What is the definition of energy?


  Energy is the capacity to do work.
• What is an energy store?


  An energy store is a system or object that contains energy in a particular form.
• In what unit is energy measured?

  Energy is measured in joules (J).
• Can energy be transferred between different stores?


  Yes, energy can be transferred between different stores.
• What are the main types of energy stores?

  1. Kinetic energy
  2. Gravitational potential energy
  3. Elastic potential energy
  4. Internal energy
  5. Electrical energy
  6. Magnetic energy
  7. Chemical energy
  8. Nuclear energy
• What type of energy does a moving car possess?

  A moving car has kinetic energy.
• What type of energy is stored in a stretched rubber band?


  A stretched rubber band has elastic potential energy.
• What type of energy is associated with a hot cup of tea?

  A hot cup of tea has internal energy.
• What type of energy is stored in a battery?

  A battery has chemical energy.
• What type of energy is stored in a magnetic field?

  Energy stored in a magnetic field is magnetic energy.
• How is energy transferred between stores?

  Energy can be transferred between different stores through various processes.
• What are the processes through which energy can be transferred between stores?

  • Work
  • Heat transfer
  • Electrical work
  • Radiation
• What happens to energy when you wind up a toy car?


  You transfer energy from your muscles into the car's spring.
• What is the principle of conservation of energy?


  The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.
• What happens to energy in a closed system according to the conservation of energy principle?


  The total energy in a closed system remains constant.
• What is often the result of energy transfers in real-world scenarios?


  Some energy is often dissipated as heat during transfers.
• How much kinetic energy will a rollercoaster have at the bottom of a hill if it starts with 1000J of gravitational potential energy?


  1000J
• Describe the energy transfers when a ball is dropped.

  1. Gravitational potential energy at the top
  2. Converted to kinetic energy as it falls
  3. Kinetic energy is temporarily stored as elastic potential energy when it bounces
  4. Converted back to kinetic energy on the rebound
• How does charging a battery work in terms of energy transfers?


  • Electrical energy from the power source is converted into chemical energy
  • This chemical energy is stored in the battery
  • Can be converted back to electrical energy when used
• Explain the energy transfers when riding a bicycle.

  • Muscles convert chemical energy from food into mechanical energy
  • Mechanical energy turns the wheels
  • This mechanical energy is converted to kinetic energy as the bicycle moves forward
• What happens in a solar panel in terms of energy transfers?

  • Light energy from the sun is converted into electrical energy
  • This electrical energy can be used directly or stored in batteries as chemical energy
• Describe the energy transfers in a wind turbine.

  • Kinetic energy of the wind is converted into mechanical energy
  • Mechanical energy turns the turbine blades
  • This mechanical energy is then converted into electrical energy by the generator
• In an electric car, what is the main sequence of energy transfers during acceleration?


  Chemical → Electrical → Kinetic (and some Heat)
• What is the role of heat in energy transfers?


  Heat is often a less useful form of energy that is dissipated during transfers.