Develop an equation for the power required, in hp, for a vehicle traveling on a level road to overcome (a) the aerodynamic drag force of the surrounding air on the vehicle and (b) the rolling resistance force on the tires. The drag force, Fd, imposed on a vehicle by the surrounding air is given by

where Cd is a constant for the vehicle called the drag coefficient, A is the projected frontal area of the vehicle, r is the air density and V is the velocity of the vehicle. The rolling resistance of the tires, Fr, opposing the motion of a vehicle is given by

where f is a constant called the rolling resistance coefficient and W is the vehicle weight. What is the equation for the power required in kW?