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      02-20-2013, 09:10 AM   #48
bruce.augenstein@comcast.
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Quote:
Originally Posted by urBan_dK View Post
This is false. CanAutM3 is correct.

The power required to overcome drag is given by 1/2ρ * v^3 * A * Cd where:

ρ is the fluid density (air in this case)
v is velocity
Cd is coeffieient of drag
A is frontal area

Bruce, you were probably thinking of force required to overcome drag, not power.
Quote:
Originally Posted by CanAutM3 View Post
I think we are saying the same thing but just to nitpick:

It is actually the force of drag that increases with the square of speed.

Power = work / time = force x distance / time = force x speed

So power needed to overcome aero drag does increases with the cube of speed.

So it takes 125 times the power to overcome aero drag at 100mph compared to 20mph .
Deal. I stand corrected.

Bruce
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