Air Resistance

IMPERIAL

The air resistance against a vehicle is a force in lbs equal to .0025 times the miles per hour squared times the frontal area.

AR = 0.0025 x MPH2 x FA

AR = Air resistance in lbs

MPH = Speed in miles per hour

FA = Frontal area of vehicle in square feet

Example:

What is the air resistance of a vehicle travelling 40 miles per hour and having a frontal area of 80 square feet

AR = 0.0025 x (40)2 x 80 = 320 lbs

METRIC

The air resistance against a vehicle is a force in newtons equal to .0462 times the kilometres per hour squared times the frontal area.

AR = 0.0462 x KPH2 x FA

AR = Air resistance in newtons

KPH = Speed in kilometres per hour

FA = Frontal area of vehicle in square metres

Example:

What is the air resistance of a vehicle travelling 65 kilometres per hour and having a frontal area of 7.5m2?

AR = 0.0462 x (65)2 x 7.5 = 1464 N