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[Phys-L] Re: thrown ball with air drag (linguistic correction)



In the following, I should have used the word "speed" throughout instead
of "velocity". I am not talking about vector relationships.

Jack



On Mon, 10 Oct 2005, Jack Uretsky wrote:

Hi all-
I've finally had a chance to look at this.
The natural scale of velocities is the terminal velocity, let's
call its value 1. The solution for if x is the inverse square of the
final velocity, and y is the inverse square of the initial velocity, then:
x=1+y.
That is, the inverse velocities (not their squares) form the hypotenuse
and vertical side of a right triangle with unit base, the hypotenuse
being the final velocity. The information encoded is that the final
velocity is always less than the initial velocity (the flight is in a
dissipative medium) and the final velocity can never exceed terminal
velocity.
The fact that the solution is expressed in squares reflects the
physical fact that the problem is not time-reversal invariant.
Regards,
Jack




--
"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn Valley