Forms of 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
Conservation of Energy
* 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
Energy and Efficiancy
* 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%)