Conservation of energy

-The total energy after a transfer is the same as the energy before the transfer, this is known as conservation of energy

-It tells us that energy cannot be created or destroyed 

-Conservation of energy applies to all energy changes 

-What energy is transferred after a bungee jumper jumps off the platform?

• When the rope is slack, some of the gravitational potential energy of the bungee jumper is transferred to kinetic energy as the jumper falls
• Once the slack in the rope has been used up, the rope slows the bungee jumper's fall. Most of the gravitational potential energy and kinetic energy of the jumper is transferred into elastic strain energy 
• After reaching the bottom, the rope pulls the jumper back up. As the jumper rises, most of the elastic strain energy of the rope is transferred back to gravitational potential energy and kinetic energy of the jumper 

-The bungee jumper doesn't return to the same height as the start. This is because some the the initial gravitational potential energy has been transferred to the surroundings by heating as the rope stretched the shortened again