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Science Forum Index » Space - Shuttle Forum » Orbital Mechanics revisited
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| Lynndel Humphreys |
 Posted: Sun Feb 11, 2007 3:38 pm |
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| Lynndel Humphreys |
| Posted: Sun Feb 11, 2007 5:23 pm |
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| > If the shuttle were to go straight up (90 degrees) at > |
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| Danny Deger |
| Posted: Sun Feb 11, 2007 11:43 pm |
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"Lynndel Humphreys" <lynndel0@earthlink.net> wrote in message
news:7PLzh.962$Jl.532@newsread3.news.pas.earthlink.net...
Quote:
If the shuttle were to go straight up (90 degrees) at
I think if it went straight up there would be no coriolis effect -- no
rotation rate relative to inertial space.
Danny Deger |
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| Maurice Barnhill |
| Posted: Tue Feb 13, 2007 9:20 pm |
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Lynndel Humphreys wrote:
Quote: If the shuttle were to go straight up (90 degrees) at
If the rocket thrust were directly upward as seen by a person on
the ground, and the launch were from any point other than the
North or South Pole, there would be a Coriolis acceleration from
the viewpoint of the ground observer.
For the rocket to remain directly above the observer who is
rotating with the earth, it must move eastward faster and faster
as it get further and further from the rotation axis of the earth
in order to stay directly overhead. That increase in speed would
require a force pointing east, which isn't available if the
rocket is thrusting straight up. So the rocket drifts westward
relative to a point at its altitude directly above the observer.
Alternatively, from the wikipedia article or any mechanics book,
omega X v is not zero. Omega points from the south pole to
the north, and the best way to see that omega and v are are
not perpendicular is to get a globe and put a pencil
perpendicular to the surface at, say, Kennedy Space Center on the
map.
--
Maurice Barnhill
mvb@udel.edu [Use ReplyTo, not From]
[bellatlantic.net is reserved for spam only]
Department of Physics and Astronomy
University of Delaware
Newark, DE 19716 |
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| John Doe |
| Posted: Wed Feb 14, 2007 1:53 am |
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Maurice Barnhill wrote:
Quote: the ground, and the launch were from any point other than the
North or South Pole, there would be a Coriolis acceleration from
the viewpoint of the ground observer.
If it went straight up, would there be Coriolis acceleration per say ? Or
would the ship simply appear to be moving towards the west because the
ground is moving towards the east ?
From what I remember, Coriolis happens when you have a northward or
soutward component in the direction. But in that case, going straight up
would not have any such component in the travel. Is that a correct
interpretation ? |
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| Maurice Barnhill |
| Posted: Wed Feb 14, 2007 10:14 am |
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John Doe wrote:
Quote: Maurice Barnhill wrote:
the ground, and the launch were from any point other than the North or
South Pole, there would be a Coriolis acceleration from the viewpoint
of the ground observer.
If it went straight up, would there be Coriolis acceleration per say ?
Or would the ship simply appear to be moving towards the west because
the ground is moving towards the east ?
The ship appearing to move west because the ground is moving to
the east *is* the Coriolis effect. Coriolis acceleration (and
centrifugal acceleration for that matter) is the appearance of
acceleration because the observer is in a non-inertial frame,
even though the body itself is in uniform motion. You can, of
course, have Coriolis and "real" acceleration happening at the
same time.
Quote:
From what I remember, Coriolis happens when you have a northward or
soutward component in the direction. But in that case, going straight
up would not have any such component in the travel. Is that a correct
interpretation ?
Coriolis acceleration due to southward or northward motion is
encountered more frequently than that due to a vertical motion,
simply because most objects stay on or very near to the earth's
surface. Nonetheless both exist and are due to the same kind of
process. In particular, a body moving north in the northern
hemisphere is getting closer to the axis of rotation of the earth
[it is aimed at the pole after all]. The earth below it is
therefore moving more and more slowly as the body goes north
[would be zero at the pole], but the body continues at its
original rotational speed. So the northward-moving body appears
to move eastward relative to the earth's surface. That is the
Coriolis acceleration.
--
Maurice Barnhill
mvb@udel.edu [Use ReplyTo, not From]
[bellatlantic.net is reserved for spam only]
Department of Physics and Astronomy
University of Delaware
Newark, DE 19716 |
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