An automobile has a characteristic length and area of 8 ft and 60 ft2, respectively.
When tested in sea-level standard air, it has the following measured drag force versus speed:
V, mi/h: 20 40 60
Drag, lbf: 31 115 249
The same car travels in Colorado at 65 mi/h at an altitude of 3500 m. Using dimensional analysis, estimate (a) its drag force and (b) the horsepower required to overcome air drag.