Energy Transfers

• Conservation of energy meaning.


  The total amount of energy in a closed system remains constant, energy cannot be created or destroyed but can change forms.
• Describe the energy changes that occur in a filament light-bulb.

  Electrical energy is transferred into light and heat energy, light is useful heat is waste.
• Describe the energy transfers for a bungee jumper.

  When falling, the GPE is converted to KE of jumper, as the chord tightens KE converted to Elastic Potential Energy (EPE), at lowest point jumper’s initial GPE all EPE.
• Explain why a bungee jumper slows down once the cord begins to stretch.

  KE decrease as it is converted to EPE, since it is proportional to (velocity)2 as KE decreases, so does velocity.
• How can unwanted energy transfer be reduced in a mechanical system?

  Reduce friction by lubricating moving parts.