# Power Needed formula. What is Area in m^2 referring to?



## EVKid (Jul 12, 2009)

Power in Watts = ((Mass in kg) (9.8m/s²) (Velocity in m/s) (Rolling Resistance)) + ((0.6465) (Coefficient of Drag) (Area in m²) (Velocity^3))

I'm just getting started here... can someone help me?

I'm using 0.2 for the Coefficient of Drag, 0.014 for the Rolling Resistance, but I'm not sure what Area in m^2 is referring to...

Mike
-I might have blown the motor on my old corolla and my boss denied my trip to Asia, if the block is cracked, I'm considering of using my new found resources for a conversion...


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## madderscience (Jun 28, 2008)

area (m^2) refers to the frontal surface area of the car. The first approximation of this is the smallest enclosing rectangle defined by the maximum width of the body, and the maximum height of the car, minus ground clearance.

And I believe it is velocity squared, not cubed.

0.2 is a pretty low coefficient of drag. Hope you found an accurate source source. 0.014 is a pretty safe rolling resistance ratio. The right tires and an alignment job and other small tweaks can get it to 0.01 without too much effort.


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## frodus (Apr 12, 2008)

m^2 is square meters. Width times height of the vehicle


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## EVKid (Jul 12, 2009)

Thanks guys, I was thinking no one was ever going to answer to this...

Mikey


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