The Geneva fountain, 107 m high, 1 MW of power
(see educanet.ch for a detailed account).
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Physics -- Units and Concepts: Power |
This is a word everyone uses and few understand. Power is to work what speed is to distance. Power is work per time. The more energy something can deliver per time unit, the more powerful it is.
If I have a miniature Japanese bulldozer, I can certainly build a dam with it but it will take me a long time to put all the earth in place. With a bigger machine, I can deliver more work per second and finish the job earlier (I also use more petrol per second). The amount of energy spent on the dam is the same in both cases. The bigger machine just handles more Joules per second than the small one.
The unit of power is the Joule per second or J/s. In honour of James Watt we call this unit also the Watt and write W.
1 W=1 J/s. The bigger unit is a thousand Joules per second or a kiloWatt or kW. The next bigger unit is again a thousand times larger, 1000 kW or 1MW or 1 MegaWatt.
Motors, light bulbs, kitchen appliances, cars: all have a power rating in W. It's how many Joules per second they are capable of consuming to do their work. But they do not need to do it all the time: they can be switched off.
The Geneva fountain, 107 m high, 1 MW of power
(see educanet.ch for a detailed account).
Confusion...
