Hi,

I am writing a phsyics engine for a car game. I am having problems understand a drag equation which I have found.

I am using the following resource.

http://www.gamedev.net/reference/articles/article1615.asp

The equation is:



Where:

C = coefficient of friction, a factor depending on the shape of a car and determined by experiment; for a late model Corvette it is about 0.30;

A = frontal area of the car; for a Corvette, it is about 20 square feet;

P = density of air = 0.0801

V = speed of the car.

If you plug in the values, you get:



Up to this point I understand.

Then the resource says the following:

"We want, at the end, to have V in miles per hour, but we need in feet per seconds for the calculations to come out right. We recall that there are 22 feet per second for every 15 miles per hour, giving us:"



What I dont understand is how they go from 0.24 to 0.517.

Any help would be great

Many thanks
Alex