View Single Post
 12-14-2012, 01:17 PM #188 (permalink) Xist Not Doug     Join Date: Jun 2012 Location: Show Low, AZ Posts: 12,115 Chorizo - '00 Honda Civic HX, baby! :D 90 day: 35.35 mpg (US) Mid-Life Crisis Fighter - '99 Honda Accord LX 90 day: 34.2 mpg (US) Gramps - '04 Toyota Camry LE 90 day: 35.39 mpg (US) Don't hit me bro - '05 Toyota Camry LE 90 day: 35.79 mpg (US) Thanks: 7,212 Thanked 2,195 Times in 1,688 Posts "Furthermore, double fuel consumption does not mean double speed (and therefore not double traveled distance per fuel unit) unless you are traveling in vacuum or talking about ridiculously low speeds. Air resistance rises as a quadratic function, so going from 50 mph to 100 mph, you will more or less quadruple your fuel consumption while only doubling your traveled distance per time." Tinduck, I am actually finishing up Physics 101. You are entirely correct. As I understand it, wind resistance is exponential because when your vehicle displaces air, you need to accelerate the air as you displace it. The idea of momentum is pretty simple, mass x velocity, but we are dealing with kinetic energy, and the formula for that is 1/2 x mass x velocity [squared]. I just figured out this regarding wind resistance! I just wanted to add that using the same formula, accelerating 0-100 MPH would require four times as much energy as 0-50, which definitely figures into fuel economy.