Difference between revisions of "Power (Physics)"
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Since d''W'' = [[Force|F]] d[[distance|x]] and [[Velocity|v]] = dx / dt follows that: | Since d''W'' = [[Force|F]] d[[distance|x]] and [[Velocity|v]] = dx / dt follows that: | ||
| − | P = F dx / dt = F v | + | P = F · dx / dt = F · v |
The usual units for power are [[Watts]] ( W = [[Joule|J]]/[[seconds|s]] ) and [[horsepower]] ( hp = 746 W ) | The usual units for power are [[Watts]] ( W = [[Joule|J]]/[[seconds|s]] ) and [[horsepower]] ( hp = 746 W ) | ||
Revision as of 03:47, October 17, 2007
In physics, power refers to the rate of transfer of energy respect to time [1].
Mathematically, average power is expressed as:
P = W / Δt
Therefore, power at any instant can be determined by the equation:
P = limΔt->0 W / Δt = dW / dt
Since dW = F dx and v = dx / dt follows that:
P = F · dx / dt = F · v
The usual units for power are Watts ( W = J/s ) and horsepower ( hp = 746 W )
References
- ↑ Serway and Beichner, Physics For Scientists and Engineers, Fifth Edition