Which expression gives the average power delivered to a system during a time interval…

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

Which expression gives the average power delivered to a system during a time interval

\Delta t

in which its mechanical energy changes by

\Delta E

? (a)

P_{\text{avg}}=\dfrac{|\Delta E|}{\Delta t}

(b)

P_{\text{avg}}=\dfrac{E_i+E_f}{2\,\Delta t}

(c)

P_{\text{avg}}=\dfrac{\Delta E}{\Delta t}

(d)

P_{\text{avg}}=\dfrac{2\,\Delta E}{\Delta t}