Using Energy

* Energy exists in difference forms- sound, light, K.E, nuclear, electrical. 

* Forms of stored energy- Gravitational Potential, elastic potential, chemical. 

* Any object above the ground has G.P.E

* A dalling object transfers G.P.E into K.E

* Not possible to create or destory energy- only possible to transfer from one form to another, or one place to another.

* The total amount of energy is always the same- Conservation of Energy and applies to all energy transfers.

* Stretching an elastic band transfers chemical energy into elastic potential energy.

* A swinging pendulam transfers energy from G.P.E to kinetic energy and back again as it swings.  

* Useful energy is energy in the place we want it and the form we need it

* Wasted energy is energy that is not useful energy

* Useful energy and wasted energy both end up being transferred to the surroundings which becomes warmer

* As energy spreads out, it gets more and more difficult to use for further energy transfers

* The energy supplied to a machine is called input energy

 Input energy = useful energy transferred + energy wasted

* The less energy wasted, the more efficiant

* No machine can be 100% efficiant 

* To make machines more efficiant by reducing friction, air resistance, electrical resistance, noise due to vibrations

Efficiancy = useful energy transferred by appliance DIVIDED BY total energy supplied to appliance (X 100%)