Re: Derive energy from angular KE of earth?

[Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU>]

So - could the gyro operate on a 'rogue' planet that is somewhere out
between the galaxies - such that the mass distribution around it
averages out to be totally symmetric - hence no mechanism for angular
momentum transfer?

Happy Holidays to All!

Bob at PC

Brian Whatcott wrote:
> Let's see: if we can all agree that a polar "Leigh" gyro changes Earth momentum
> when electrical power is generated, then the complementary momentum is
> taken out
> from the 'system' - lacking a Moon, then from the Solar system - lacking a
> solar
> system, from the Milky Way.
> There - is that unrealistic enough to have appeal?
>
> :-)
>
> Brian W
>
> At 09:23 AM 12/24/2003, you wrote:
> > The Moon don't enter into it!
> >
> > We can banish the moon and the generator still works. Not so with the tidal
> > effects.
> >
> > Buone feste!
> >
> > Mark
> >
> > At 07:08 24/12/03 -0600, Brian Whatcott wrote:
> > > I offer this 'anti-physicist' thought.
> > > No observable effect at all depends on whether a physicist can explain it.
> > >
> > > So I will, instead  :-)
> > > If there were a physicist's kind of gyroscope - you know, the one with
> > > frictionless
> > > bearings and zero air resistance and no eddy current losses, then we can
> > > say the
> > > gyro's momentum would remain intact, and the stored momentum of the Earth
> > > changes as electrical power is generated (in Leigh's idealization).
> > >
> > > It is this change that is comparable to tidal drag (at least, if the gyro
> > > is in the
> > >   polar regions.) The change of Earth momentum
> > > is countered by the change in Earth Moon momentum as I recall.
> > >   I am tempted to suppose that in lower latitudes, there can be
> > > precessional modes
> > > excited, but I have not thought much about the differences....
> > >
> > > If we have to cope with an engineer's gyro, then the enhanced side force on
> > > the gyro's pivots allow that device to spin down and lose momentum too.
> > >
> > > Merry Christmas.
> > > Brian W
> > >
> > > At 02:57 AM 12/24/2003, you wrote:
> > > > Brian, we agree that the KE of the system decreases, but for the angular
> > > > momentum to decrease we must find an external torque or else show how the
> > > > mass distribution changes to produce a change in the moment of inertia so
> > > > that the angular momentum does not change. (Take a look at Leigh Palmer's
> > > > gedankenapparat (unfortunately described under the subject line "phys-l
> > > > digest")). About the axis of the generator, you first bring the generator
> > > > rotor + gyroscope to rest (seen from a non-rotating frame), and use the
> > > > gyroscope flywheel spinning about a perpendicular axis to keep it there
> > > > while the earth continues to spin. Note that you will have exchanged ang.
> > > > mom. between earth and rotor in the process. Now when you use the
> > generator
> > > > to do work there is an electromagnetic torque between the rotor and the
> > > > earth - angular momentum is again exchanged between these parts of the
> > > > system. This is not the answer, however, since we can go on doing work
> > with
> > > > the generator for as long as we want, it seems to me. I note that there
> > > > must also be a precession caused about the third perpendicular axis when
> > > > you do work with the generator, but this only seems to complicate matters
> > > > as far as ang. mom. conservation is concerned. Mark
> > > >
> > > > At 23:01 23/12/03 -0600, Brian Whatcott wrote:
> > > > > Perhaps I am not fully conscious of the effect you're pondering.
> > > > > I am supposing that you spin up a flywheel, providing complementary m=
> > > > > omenta,
> > > > > then extracting momentum from the disk, with the identical reduction
> > > > > to the complementary agency?
> > > > >
> > > > > Perhaps you are considering the case of generating energy without
> > > > > losing momentum.   A perpetual motion, kinda?
> > > > >
> > > > > Brian W
> > > > >
> > > > > At 08:34 PM 12/23/2003, you wrote:
> > > > > > Well, it is true that spinning up the flywheel will transfer angular
> > > > > > momentum to the earth, but after that, if the bearings are really go=
> > > > > od,
> > > > > > there will be a very small amount of angular momentum transferred be=
> > > > > tween
> > > > > > the wheel and the earth.
> > > > > >
> > > > > > Fred Bucheit
> > > > > >
> > > > > > > From: Brian Whatcott <betwys1@SBCGLOBAL.NET>
> > > > > > >
> > > > > > > How about treating the angular momentum as a storage method.
> > > > > > > Spin up a flywheel, and the Earth takes up a complementary
> > > > > > >   momentum (if you must...)
> > > > > > >
> > > > > > > Brian
> > > > > > >
> > > > > > > At 10:01 PM 12/22/2003, you wrote:
> > > > > > > > [This was brought up on PHYSHARE-L as well, and I still don't ge=
> > > > > t how
> > > > > > > > rotational momentum is conserved. I realize that when I fully un=
> > > > > derstand
> > > > > > > > it, I am going to feel like an idiot, but here goes....]
> > > > > > > >
> > > > > > > > If the energy that is used to light the bulbs, etc., comes from =
> > > > > the
> > > > > > > > earth's rotation, then the earth needs to lose kinetic energy. K=
> > > > > E of a
> > > > > > > > rotating body is KE =3D 1/2 (rotational inertia) (rotational vel=
> > > > > ocity)^2. I
> > > > > > > > presume that the actual shape of the earth doesn't change, so it=
> > > > > s
> > > > > > > > rotational inertia remains constant. That means that rotational =
> > > > > velocity
> > > > > > > > must decrease.
> > > > > > > >
> > > > > > > > On the other hand rotational  momentum =3D rotational inertia x =
> > > > > rotational
> > > > > > > > velocity . If rotational inertia stays the same and rotational v=
> > > > > elocity
> > > > > > > > decreases, then rotational momentum must get smaller. If rotatio=
> > > > > nal
> > > > > > > > momentum of the earth gets smaller, then the L of something else=
> > > > >  must get
> > > > > > > > larger.
> > > > > > > >
> > > > > > > > So, the rotational momentum of what gets larger?
> > > > > > > >
> > > > > > > > Marc "Zeke" Kossover
> > > > > > > > The Hockaday School
> > >
> > > Brian Whatcott    Altus OK    Eureka!
> >
> > Mark Sylvester
> > UWCAd
> > Duino Trieste Italy
>
> Brian Whatcott    Altus OK    Eureka!