A car is going up a road with a $5\%$ grade at a constant speed of $60m\frac{i}{h}$ at a location where

${}_{\text{a}\text{i}\text{r}}=0\mathrm{.}0025$slu$\frac{g}{f}{t}^3.$ The car's frontal area is $20f{t}^2,$ for which the drag coefficient is $0\mathrm{.}30.$ The

efficiency of the car engine is $90\%.$ If the car weighs $1800$ lb $,$ how much horsepower $($hp$)$ is

the car's engine generating?

$P=17,292\mathrm{.}98ft-lb\frac{?}{s}=31\mathrm{.}44hp$