Energy, Work and Power
- Energy: amount of work and its measured in Joules (J)
- ^^Conservation of energy:^^ energy cannot be created or destroyed, when work is done, energy is changed from one form to another. * Energy can be stored
- A book on a shelf has g.p.e , if it falls of the shelf it will have k.e
| Energy type | What it is |
|---|---|
| Kinetic | Due to motion |
| Gravitational | From potential to fall |
| Chemical | In chemical bonds |
| Strain | Compress/stretch |
| Nuclear | Atoms rearranged/split |
| Internal | Motion of molecules |
| Electrical | Carried by electrons |
| Light | Carried in light waves |
| Sound | Carried in sound waves |
- Due to the processes through which energy transfers take place not being 100% efficient
- energy is lost to the surrounding and therefore energy gets more spread out (dissipated)
- ^^Efficiency:^^ ^^how much useful work is done with energy supplied^^
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Energy Resources
- ^^Renewable sources:^^ Energy sources that are not exhaustible/ Infinite
- ^^Non-renewable sources:^^ Energy sources that are exhaustible/ finite
Work and Power
- ^^Work^^: Work is done whenever a force acts on an object that moves (or is moving) in the direction of the force * The greater the force, the greater the work * The larger the distance moved, the larger the work
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- Whenever any work is done, energy gets transferred (mechanically) from one form to another
- The amount of energy transferred (in joules) is equal to the work done (also in joules) * ^^energy transferred (J) = work done (J)^^
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Work done = Force x Distance travelled
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^^Power:^^ is the rate at which a machine transfers energy
The greater the rate at which energy is transferred, the greater the power * Because work done is equal to energy transferred, the power is also equal to the rate of doing work
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- Power = Energy/time
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