Power is quite an important concept in physics. When we talk about how "powerful" something is we generally think of how strong something is. In science though, "power" is a measure of the rates at which work is done. If we have two machines A and B, and B performs more work in the same time as machine A, we would regard machine B has being the more powerful of the two.


To put this mathematically, power is a measure of the amount of work done in a given time. Work is measured in Joules and time of course is measured in Seconds, so the amount of work done is the number of joules divided by the number of seconds.



The unit that we use for power, is the Watt so it follows that the amount of Watts is the number of Joules divided by the number of seconds:



In GCSE you are not likely to see the second depiction (s-1), this seems to be favoured in A level study.


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