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Re: Weightlessness



It is not very often that Marilyn Savant is inaccurate in her replies. Well...I guess Physics is one subject where there are ample opportunities to be factually inaccurate.

-Hasan Fakhruddin

<<< emosca@PTD.NET 5/20 7:59a >>>
The letter and answer below came from Marilyn vos Savant's column in today's
Parade Magazine. I thought some of you might find Marilyn's answer as
edifying as I do.


Earth's gravity holds spaceships in orbit, but the things inside them are
weightless and float around. Why doesn't gravity have an effect inside?
*-Jerry Mapes, city unknown

Actually, it does*-the same way it affects the spacecraft itself. When a
space shuttle is orbiting the Earth, the sum of the ³downward"
(gravitational) force and the "forward'' (inertial) force of the moving ship
and its contents nearly equals zero. So both the ship and its contents are
in freefall, which makes everything weightless. They stay in orbit while
"falling'' (being pulled toward the Earth) because the inertial force
(centrifugal force, in this case) of the moving vehicle is radial*-away from
the Earth. A similar principle applies to the planets: All are in glorious
free-fall while orbiting within the gravitational field of the Sun.


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