Gene,
You are using non-inertial reference frames, which can give rise to
pseudoforces (such as centrifugal force). I know that NASA is fond of this.
I'll stick by classical physics, thank you.
Jim
[email protected] wrote:
Jim,
Here are several corrections of your statements. See below.
---- Original message ----
Date: Sun, 25 Jan 2009 18:38:55 -0600
From: James Frysinger <[email protected]>
Subject: [USMA:42574] Re: The real physics (was Small item seen on TV)
To: "U.S. Metric Association" <[email protected]>
...
The astronauts orbiting the Earth are not weightless.
False. There weights are nearly zero with respect to their immediate surroundings. They
are "weightless" in first approximation in the reference frame of their
spacecraft.
Their gravitational weight is the centripetal force that pulls them around in
orbit.
False. The central force accelerates them toward the center of the earth, but
it is perpendicular to their direction of motion in the orbit.
Likewise, their orbiter's weight pulls it around in orbit.
False. There is no tangential pull (thrust) and little drag on the spacecraft in parking orbit.
...
*With the earth as the frame of reference*:
The weight of an object at Shuttle Orbiter altitudes is >roughly 92 % of its
weight on the surface of the Earth. At >ISS altitudes it's roughly 91 %.
*With the orbiter as the frame of reference*:
...the astronauts are in orbit with their orbiter and since >both experience the same
centripetal acceleration, the >astronauts feel "weightless" and float around inside
the >orbiter.
A similar phenomenon can be experienced (briefly) in an >elevator whose cable
has been cut...
I have no quibble with your elevator and other examples.
Gene.
--
James R. Frysinger
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Doyle, TN 38559-3030
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