2.3.3 Calculating Energy Transfers

• Energy transfer

  The process of energy moving from one store to another, often involving a change in the form of energy
• Energy Stores

  • Kinetic Energy
  • Gravitational Potential Energy (GPE)
  • Elastic Potential Energy
  • Thermal Energy
  • Chemical Energy
• Kinetic Energy


  Energy of a moving object
• Gravitational Potential Energy (GPE)

  Energy stored in an object due to its height above the ground
• Elastic Potential Energy


  Energy stored in a stretched or compressed object
• Thermal Energy

  Energy stored in an object due to its temperature
• Chemical Energy


  Energy stored in chemical bonds, such as in food or fuel
• Kinetic Energy Calculation

  KE=12×1000 kg×(20 m/s)2=200,000 J
• Gravitational Potential Energy Calculation

  GPE=2 kg×9.8 m/s2×5 m=98 J
• Elastic Potential Energy Calculation

  EPE=12×100 N/m×(0.2 m)2=2 J
• Work Done Calculation

  Work Done=50 N×3 m=150 J
• Efficiency Example

  Efficiency=150 J/200 J×100%=75%
• Understanding how to calculate and analyze energy transfers helps you grasp how energy moves and changes form in different physical processes, which is a core part of physics
• Energy transfer

  The process of energy moving from one store to another, often involving a change in the form of energy
• Energy Stores

  • Kinetic Energy
  • Gravitational Potential Energy (GPE)
  • Elastic Potential Energy
  • Thermal Energy
  • Chemical Energy
• Kinetic Energy


  Energy of a moving object
• Gravitational Potential Energy (GPE)

  Energy stored in an object due to its height above the ground
• Elastic Potential Energy


  Energy stored in a stretched or compressed object
• Thermal Energy

  Energy stored in an object due to its temperature
• Chemical Energy


  Energy stored in chemical bonds, such as in food or fuel
• Kinetic Energy Calculation

  KE=12×1000 kg×(20 m/s)2=200,000 J
• Gravitational Potential Energy Calculation

  GPE=2 kg×9.8 m/s2×5 m=98 J
• Elastic Potential Energy Calculation

  EPE=12×100 N/m×(0.2 m)2=2 J
• Work Done Calculation

  Work Done=50 N×3 m=150 J
• Efficiency

  Measure of how much input energy is usefully transferred
• Understanding how to calculate and analyze energy transfers helps you grasp how energy moves and changes form in different physical processes, which is a core part of physics