1.1.11 Conservation & Dissipation of Energy

• Conservation of Energy


  The law states that energy cannot be created or destroyed, only transferred or transformed
• The total amount of energy in a closed system remains constant
• Closed System


  A system where no energy enters or leaves
• Energy Transformations

  Energy can change forms but the total energy within the system remains unchanged
• Examples of energy transformations

  • Pendulum
  • Roller Coaster
• Pendulum swings

  Gravitational potential energy converts to kinetic energy and back
• Roller coaster descends

  Converts gravitational potential energy to kinetic energy
• Roller coaster climbs

  Converts kinetic energy back to gravitational potential energy
• If a ball falls, its gravitational potential energy decreases while its kinetic energy increases by the same amount
• Dissipation of Energy


  The process where energy is spread out or "lost" to the environment
• Heat Loss

  Energy is often lost as heat due to friction between surfaces or air resistance
• Sound


  Energy can also be dissipated as sound, often a byproduct of mechanical processes
• Irreversibility


  Dissipated energy generally cannot be fully recovered or converted back into useful work
• Examples of energy dissipation

  • Friction
  • Electrical Devices
• In mechanical systems like car engines

  Energy is lost as thermal energy due to friction
• In a light bulb

  Electrical energy is partly converted into light and partly dissipated as heat
• Insulation

  Using insulating materials can reduce heat loss in buildings and appliances
• Lubrication

  Reducing friction by using lubricants in machinery can minimize energy loss due to heat
• Efficient Design

  Designing devices to be more energy-efficient can reduce unnecessary energy dissipation
• 450,000 joules of energy is dissipated as heat and sound due to friction
• Higher efficiency means less energy is wasted