thought experiment

Ted Gallop ( gallope@planet.curtin.edu.au )
Thu, 28 Oct 1999 14:44:19

>Anyone game to tackle this?
>
>For computational purposes we will assume a diameter of the earth of
>24,000 miles with the resultant velocity of 1000 MPH or 1600 KPH. We are on
>the equator. We have a small pad on the ground exactly at sea level that
>has the ability to neutralize the gravity of an object instantaneously, in 0
>time. We have three spheres of 1 meter each. One is pure iron, one is
>pure copper, and one is pure silicon. Other than the weight difference, one
>is magnetically and electrically conductive, one is electrically but not
>magnetically conductive, and one is neither.
>
>The neutralization does just that, it does nothing but render the
>spheres absolutely neutral insofar as gravitional attraction, but retains all
>other properties of the respective materials. In relation to the point where
>it was neutralized, can anyone predict what each sphere would do after it
>was neutralized and considering all other physical forces and energies which
>it would be subject to other than gravity?>
>
>Dave Nelson

Hi David et al,

I don't think much would happen at all from the magnetic or electrical
perspective, but they would all 'shoot' vertically up from the earth into
the sky, at about 268 mph.

IRON-The magnetic qualities of the iron sphere are irrelevant. After all,
the sphere would be equally attracted to the South as to the North so they
magnetic forces would be 'neutral'. Magnetic attraction works in both
directions on a non-magnetised item (Both ends of a magnet attract iron)

COPPER-The copper sphere would would, I think, have the same result. If
there were any 'electrical' forces out there the copper sphere would once
again, on being released from gravitational force, be in a 'neutral' state
where the attraction/force in any direction was equal to the
attraction/force in another.

SILICON-As with the others, would not do much at all.

ALL Cases- Each 'sphere' would have a tendency to continue in its state of
motion att he same rate of speed as the earth rotates. However, the spheres
would travel in a straight line and the earth's surface would 'recede' from
the spheres as it rotated in a circle and they tangentially headed into
space. To an earth observer they would appear to go straight up. But the
rate of divergence from the earth's surface, i.e. the rate at which they
appear to 'rise' (relative to the earth) would not be great. In fact, the
earth's surface direction change is only 15 degrees per hour. So the rate
of rise would be (if my trigonometry serves me correctly) at tan 15 x rate
of rotation, which is (if the earth is rotating at 1000mph) 268 MPH.

The only additional influence might be some restricion on the acceleration
of the iron sphere as it leaves the influence of the earth's magnetic
field. Similarly, there may be some electrical force that effects this
acceleration with the copper sphere. However in both cases these would be
weak compared with the inertial force (centripetal - or is it centrifugal -
whichever is the force causing the spheres to keep going outward at a
tangent) that causes the sphere to keep going.

With all the spheres (especially the silicon) it's WHAMMOOO0ooooooooooo.......

Cheers,
Ted Gallop

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