Pendulum: energy transfers

• Conservation of energy


  Energy can be transferred usefully, stored or dissipated, but it cannot be created or destroyed
• Energy transfer within a system

  1. Gravitational potential energy at the top

  2. Kinetic energy at the bottom

  3. Gravitational potential energy as it swings back up
• Friction causes energy to be transferred to thermal energy stores
• Friction


  Causes the pendulum to gradually swing with less energy and eventually stop
• Closed system


  • No energy can enter or leave the system
• Reducing friction, e.g. using a lubricant, can reduce unwanted energy transfers