A $1750-$kg car coasts down a hill inclined at an angle of $=15\mathrm{.}0.$ The car is acted on

$$

by three forces: $($i$)$ the normal force exerted by the road, $$

$,($ii$)$ a force due to air

resistance, $$ air, and $($iii$)$ the force of gravity, $$

$.$ Find the total work done on the car as it

coasts $25\mathrm{.}5$ m down a hill. Let the force due to air resistance be $25\mathrm{.}0$ N$.$