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Re: What is weight?



It is virtually impossible to imagine a distribution of masses that give
rise to a uniform gravitational field over an extended region. The field
in a spaceship is uniform enough for practical purposes of course,
but when one is considering the question of relativity of frames in
gravitation, it is important that when considering an extended region
(say in the Earth's field) it is NOT equivalent to an accelerated frame.
It cannot be completely transformed away by getting in an accelerated
frame.

Thus there are tidal forces (different pull at your head and at your
feet, slightly different directions also from the sides of your body
(radial field)). While these are trivial near the Earth, if you were in
orbit near a black hole these tidal forces could pull you apart.