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## Homework Statement

I know that standard formula is, FD = 1/2 CD *ApV^2

FD = Drag Force. SI: N

CD = Drag Coefficient. SI: Dimensionless (Typical Values)

A = Coss-sectional Area perpendicular to the flow. SI: m2

r = Density of the medium. SI: kg/m3

v = Velocity of the body relative to the medium. SI: m/s

But our prof also said theres another formula for drag force,

FD = 1/4 AV^2

(Its is not supposed to be equal but approximately)

So the question is when is the equation above false, whats the error in the equation that makes it approximate.

## Homework Equations

FD = 1/4 AV^2

FD = 1/2 CD *ApV^2

## The Attempt at a Solution

I searched everywhere on wikipedia and NASA site and no luck and I dont know integration yet so can't follow the complicated math. Please anyone can help me.