Ulisse wrote:I had to look it up, but you are right. Drag does increase with speed, but it would be felt more on something like amotorcycle than a car and the more aerodynamic the shape the less effect drag would have.The more turbulence caused by the car/mortocycle the more drag.
Look it up some more, my friend, and soon we will have the exact formula.
But again off the top of my head, you are talking about Coefficient Of Drag -- Cd (or some such symbol). A sports car might have a Cd of 0.3, while a pickup might have 0.4. The lowest Cd in the world is the shape of a raindrop.
Roughly, the formula for drag is something like:
Cd x frontal area x speed squared.
Again, probably not precise, but the concept.
Ygmir, it is all a matter of degree, and/but some of the factors change exponentially (thanks Joe, I couldn't think of that word). And yes, air and water behave the same way -- they just have different viscosity. If you wanted to compare MPG between a car and a boat -- PROVIDED THE OTHER FACTORS COULD BE THE SAME
(let's say you wanted to compare the internal efficiency of the engines but did not have a test bench) -- you would have to add the fluid viscosity to the formula.
This is a very interesting field. For example, there is something called the boundary layer. The air that is closest to the car-body actually stands still in relation to the car, no matter how fast the car is moving in relation to the surrounding air. Of course, we are talking about a thickness of molecules. Then the boundary layer ends where the air is up to full speed. The boundary layer creates turbulence. Polishing the car helps.