A vehicle is built to try for the land-speed record at the Bonneville Salt Flats, elevation \(4400 \mathrm{ft}\). The engine delivers \(500 \mathrm{hp}\) to the rear wheels, and careful streamlining has resulted in a drag coefficient of 0.15 , based on a \(15 \mathrm{ft}^{2}\) frontal area. Compute the theoretical maximum ground speed of the car

(a) in still air 

(b) with a \(20 \mathrm{mph}\) headwind.