Re: Air Resistance

[John Mallinckrodt <ajmallinckro@CSUPomona.Edu>]

On Wed, 10 Dec 1997, LUDWIK KOWALSKI wrote:

> The  reference for the empirical formula: "Analytical Mechanics" by 
> G.R. Fowles and G.L. Cassiday, Fifth Edition, 1993, page 62. It is the
> usual c1*v+C2*v^2 description. For a sphere of diameter D the empirical
> values are:  c1=1.55*10^-4*D and c2=0.22*D^2, all in SI units.

It's worth noting that the empirical formula implies that quadratic drag
becomes dominant at speeds greater than (7 x 10^-4)/D (in SI units).  For
Ludwik's basketball this is about 3 mm/s, about 600 times less than the
smallest velocity reported.  This result agrees with my own previous
understanding of the exceedingly low velocities at which viscous drag
ceases to be a viable model for macroscopically sized objects moving
through air.

John
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