Pheesics Pouer

As a rate o chynge o wirk duin or the energy o a subseestem, pouer is:

${\displaystyle P={\frac {W}{t}}\,}$

whaur P is pouer, W is wirk an t is time.

The average pouer (aften juist cried "pouer" whan the context maks it clear) is the average amoont o wirk duin or energy transferred per unit time. The instantaneous pouer is than the limitin vailyie o the average pouer as the time interval Δt approaches zero.

${\displaystyle P=\lim _{\Delta t\rightarrow 0}{\frac {\Delta W}{\Delta t}}=\lim _{\Delta t\rightarrow 0}P_{\mathrm {avg} }\,}$

Whan the rate o energy transfer or wirk is constant, aw o this can be simplifee'd tae

${\displaystyle P={\frac {W}{t}}={\frac {E}{t}}}$,

whaur W an E are, respectively, the work duin or energy transferred in time t (for ordinar measured in seicont).