Conservation of Energy Principle

Key Concepts

• Conservation of Energy: Energy can be transferred, stored, or dissipated but cannot be created or destroyed.
  • Energy moves between different objects and forms.

Application Example

• Phone Charging:
  • Electrical energy from a wall socket transfers to the chemical energy store in the phone's battery.
  • When using the phone:
    • Chemical energy converts back to electrical energy.
    • Electrical energy powers components like the screen and speaker.
    • Screen: Electrical energy → Light energy.
    • Speaker: Electrical energy → Sound energy.

Energy Transfer

• Ideal: All energy is transferred usefully to the desired store.
• Reality: Some energy is dissipated as wasted energy (often as heat).
  • Example: Phone warming up during use.
  • Other forms: Sound energy.

Systems in Physics

• System: A portion of the universe chosen for analysis; the rest is the environment.
• Open System:
  • Energy and matter move freely between the system and environment.
  • Example: A phone not in a sealed container.
• Closed System:
  • Energy and matter cannot enter or escape the system.
  • Example: A phone in a sealed jar with air.
  • Important: Overall energy in a closed system remains constant.

Conclusion

• Understanding and applying the conservation of energy in different scenarios is crucial.
• Systems can be open or closed, affecting how energy and matter interact with the environment.