if net Force is not equal to 0, then it accelerates the Fluid (since F = ma), causing variation in velocity, which is not a Fully Developed Flow. Hence Forces are equally balanced such that the initial inertia of the Fully Developed Flow is not changed.
18:06 too important concept why net force zero
if net Force is not equal to 0, then it accelerates the Fluid (since F = ma), causing variation in velocity, which is not a Fully Developed Flow. Hence Forces are equally balanced such that the initial inertia of the Fully Developed Flow is not changed.