Subject:
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Re: John Leo's opinion of "The West Wing"
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Newsgroups:
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lugnet.off-topic.debate
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Date:
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Thu, 3 Oct 2002 17:56:11 GMT
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Viewed:
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984 times
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In lugnet.off-topic.debate, Dan Boger writes:
> Quoting David Koudys <dkoudys@redeemer.on.ca>:
> > Would it be a $#*crash*#$ into the side or more of a 'rubbing' every once
> > in a while to stop the sideways velocity.
>
> I think it'll feel like you're rolling down a steep hill, constantly crashing
> against the eastern wall.
>
> > Considering that gravity is pulling straight down, and the original
> > velocity
> > from the surface spin is moving you east at whatever kph, would the gravity
> > effectively cancel out the sideways velocity over the distance of the
> > tunnel, even tho the closer you get to the center of the earth, the slower
> > the sideways velocity is along the tunnel.
>
> uh, why? gravity is pulling straight down, your momentum is at 90 degs to the
> force - gravity will NOT AFFECT your sideways motion one bit. I won't cancel
> it out, or slow you down. The only thing slowing down your sideways momentum
> (in a painful way) would be the side of the tunnel.
>
> > I mean, there is this sideways velocity, but the farther the mass goes 'off
> > center' from straight down, the more gravity would tend to pull that mass
> > back to center.
>
> if you were free falling in orbit, that would kind of be correct. at the right
> speed, at the right distance from earth, you might even go into stable orbit.
> However, if you only have 8' of sideways motion available, gravity if for all
> practical considerations perpendicular to you, and therefore will not change
> your lateral speed.
Now that I pictured that, I understand it better--the force of gravity is
always pointing straight to the center from the object, even if you're a
foot to the right from where you were a second ago--my visual image is
reprocessed--thanks!
>
> [snip]
>
> > And reading Frank's example about the onion and the layers, the effective
> > mass for attracting an object is lessened as we fall down the hole--I think
> > this means that our 'terminal velocity' speed would lessen as we get closer
> > to the center, so does this, in turn, mean that the closer we get to the
> > center of the planet, the slower we would fall--that we wouldn't have to
> > get
> > past the center before we start slowing down, due to being pulled back to
> > the center?
>
> yup - you won't slow down as you near the center, you'll just accelerate more
> slowly. To slow down a force need to be applied to your falling (flailing?)
> body.
*arms and legs flailing in the air*...
But if we deal with the idea of terminal velocity, that brings the air
resistance into the 'hypothetical' idea... without terminal velocity (air
resistance) I'd swing just as far up the other side as my initial starting
position.
So as the air resistance works against the falling mass, and the gravity
lessens, the mass will slow down.
So it won't be a straight line, or even a simple arc (if we don't want to
hit the walls of the tunnel), but a spiral to the center of the planet.
K, completely ravamping my childhood idea here.
But wait (he says trying to readjust...)
The velocity at the surface of the tunnel and the velocity of the mass to
the east are the same, and would probably be a negligible change for the
first few meters of the mass falling...
Then as the velocity of tunnel decreases the farther down the tunnel (like a
bike spoke--closer to the center, the slower it moves if the wheel is
rotating), and if we didn't want to hit the walls of the tunnel, the tunnel
would have to start swinging east, taking us away from the center of the
planet, and eventually end up, as Dan said, in a stable orbit at some point
above the center of the planet.
But then there's wind resistance, and that throws a whole different kettle
of fish into the mix... the path of the tunnel might end up looking like an
upsidown question mark.
So, basically for me, we're back to making the tunnel go from the north pole
to the south pole, where the easterly velocity is a moot point, and we only
have to factor in terminal velocity and the lessened gravity as we approach
the center.
> [snip]
Dave K.
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Message has 1 Reply:
Message is in Reply To:
 | | Re: John Leo's opinion of "The West Wing"
|
| Quoting David Koudys <dkoudys@redeemer.on.ca>: (...) I think it'll feel like you're rolling down a steep hill, constantly crashing against the eastern wall. (...) uh, why? gravity is pulling straight down, your momentum is at 90 degs to the force - (...) (22 years ago, 3-Oct-02, to lugnet.off-topic.debate)
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