Physics

Problem

A car of mass

1000\,\text{kg}

moves on a straight road. Its engine produces a forward driving force of

8000\,\text{N}

. The resistive force of air is

F_{\text{air}}=50v

, where

v

is the speed in

\text{m\,s}^{-1}

. Find the net instantaneous power exerted on the car when its speed is

20\,\text{m\,s}^{-1}

. a)

1.8\times10^{5}\,\text{W}

1.4\times10^{5}\,\text{W}

7.0\times10^{4}\,\text{W}

1.6\times10^{5}\,\text{W}