Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: A bawl in a rotating dish (was Hot air rising ...)



At 06:06 7/28/99 +0100, you wrote:
Clever. But I do not see why should the surface be parabolic?
...Spherical
surfaces, however, are easier to create than parabolic.
Ludwik Kowalski

Robert A Cohen wrote:

How about spinning a parabolic surface about its center? At a particular
rotation rate, a ball placed on its surface and at rest relative to the
surface will stay stationary relative to the surface....

I believe there is virtue in Ludwik's comment.
A concave surface of rotational symmetry will serve Robert's purpose,
I fancy. Robert has the inverse case in mind, I imagine - that the
equipotential surface of revolution is parabolic - to which spun
mercurial mirrors conform.
Perhaps the parabola has a virtue: that though one could hope for
stasis in the mirror's frame at only one rotational speed, the
"apparent incline" is linear at different speeds and provides a
centrifugal or centripetal direction.


brian whatcott <inet@intellisys.net>
Altus OK