2.3 Useful Energy
A machine is something that transfers energy from one form to another.
The energy we recieve consists of:
· Useful energy - has been transferred to the place and form we want.
· Wasted energy - has not been usefully transferred
Both useful and wasted energy will eventually be transferred to the surroundings, which will be heated up. Energy is often wasted due to friction although some friction is useful.
As energy spreads out it becomes more and more difficult to use for further energy transfers.