etermine the horsepower developed by a passenger car traveling at a speed of 70 mi h on an upgrade of 9 percent with a mooth pavement The weight of the car is 4 500 lb and the cross sectional area of the car is 35 ft Assume the density of air is 0766 lb ft and the aerodynamic drag coefficient is 0 4 Use the following equation for the rolling resistance R in lb R Crs 2 15C W or which C 0 012 C 0 650 x 10 6 sec ft2 u is the vehicle speed in mi h and W is the weight of the vehicle in lb