[amsat-bb] Re: AMSAT-NA totally metric? and now almost totally off topic.
lucleblanc6 at videotron.ca
Mon Jan 22 02:33:46 PST 2007
On 22 Jan 2007 at 17:43, Tony Langdon wrote:
> At 03:38 PM 1/22/2007, Sil - ZL2CIA wrote:
There is a lot of folks who experience free falls in their dreams...it is
probably not related to gravity but as much scary than a real one. Could be a
dream interpreter can be usefull here.
As Einstein says all is relative to the context the astronauts are falling but
they don't feel it as they remain at the same level.
Is the astronauts make also free falling dreams?
Back to normal programming...
> >Are you really weightless in space? Surely you're just in free fall.
> >When the term "weightless" is used to describe the condition
> >astronauts experience, this is surely a literary term, rather than a
> >scientific one.
> As it turns out, the answer is "yes" or "no". It depends on your
> frame of reference and the definition you use. Using the definition
> that weight is the force exerted by gravity, then one would presume
> at a point near the Earth - Moon L1 point, you would be very nearly
> weightless (there would be some unbalanced gravitational influence of
> the Sun most of the time, but you could move around and null that out too...).
> >Why spend the $20.000.000 (or 20,000,000 if that's your custom) you
> >mention, when you could achieve that same "weightlessness" by
> >jumping out of a building (if for a shorter time, of course, and
> >with a riskier outcome).
> A _much_ shorter time (remember air resistance quickly builds up so
> you soon have the same reaction force from air resistance as you do
> standing on the ground - i.e. you quickly reach terminal velocity).
> >Am I weightless when I jump off a chair?
> Depends who you ask, but most physics sources do say "no" as they
> define weight purely in terms of gravitation.
> >Are orbiting satellites "weightless"?
> See above, but after looking at a number of sources, I'll concede
> "no" (assuming the strict gravitational definition of weight).
> 73 de VK3JED
Luc Leblanc VE2DWE
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