Re: Vertical fall. A paradox?

[LUDWIK KOWALSKI <KOWALSKIL@alpha.montclair.edu>]

> A spherical object is moving vertically down through a medium, such as air 
> or water. The potential energy decreases. Initially a large fraction of PE
> is converted into translational KE but eventually this conversion process 
> stops (at the macroscopic level) and PE is converted into Q only. ....

Now suppose the object is a  rigid "bomb" whose fins are twisted. Its 
rotational kinetic energy (spinning about the vertical axis) also increases 
at the expense of potential energy. Will the angular velocity continue to 
increase after the terminal linear velocity is reached? What is the  maximum 
possible rotational energy? We know that KErot can not exceed (m*g*h-KEtt), 
where KEtt is the terminal translational KE. In fact, KErot must be smaller 
than (m*g*h-KEtt) because part of the initial potential energy is thermalized.
What mechanism is responsible the "terminal angular velocity"? Why should the 
net torque be zero at some rate of rotation? Constant terminal torque? Yes. 
Constant terminal omega?  (???).
                                                         Ludwik Kowalski