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Author Topic: Is the Coriolis effect, as applied to missiles, wrong?  (Read 2344 times)

Offline mrsmith2211

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According to NASA "To an outside observer, who is occupying another reference frame, there is no deflection and the motion is a straight line."

Would this mean observed from space the path of a missile is straight?

How could this be explained? No effect when shot along the eqauator.

Because of the axis tilt of earth and earth's rotation, from the time of the missile firing and hitting ground the target has moved, thus necessitating corrective calculation attributed to the coriolis effect.

Would there be a coriolis effect if the earth's axis was not tilted? I think not.
« Last Edit: 21/12/2015 23:24:55 by chris »


 

Offline evan_au

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Re: Coriolis effect as applied to missiles is wrong.
« Reply #1 on: 21/12/2015 20:01:53 »
Quote from: mrsmith2211
Would there be a coriolis effect if the earth's axis was not tilted?
Yes.

There would be no Coriolis effect if the Earth were not rotating (but that would totally mess up your life in other ways...)
 

Offline mrsmith2211

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Re: Coriolis effect as applied to missiles is wrong.
« Reply #2 on: 21/12/2015 22:53:48 »
The earth is rotating, many sites attribute gravitational whatever to changing the path of the missile, the path of the missile does not change, only the observed path from the earth point of view.
 

Offline Space Flow

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #3 on: 22/12/2015 03:00:01 »
Would there be a coriolis effect if the earth's axis was not tilted? I think not.
As stated by Evan above, the Coriolis effect is due to the Earths spin on it's axis and not on the amount of axis tilt. The effect would be the same at any angle of axis tilt, as long as the rate of spin remains the same.
 

Offline mrsmith2211

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #4 on: 22/12/2015 03:08:15 »
The question I would ask if a planet was spinning on a perpendicular rather than tilted axis  would there be a perceived Coriolis effect.
 

Offline Space Flow

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #5 on: 22/12/2015 03:36:52 »
The question I would ask if a planet was spinning on a perpendicular rather than tilted axis  would there be a perceived Coriolis effect.
Perpendicular to what? If you mean at an axial tilt of 90 degrees, than the answer is yes. It would be the same at any axial tilt.
 

Offline mrsmith2211

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #6 on: 22/12/2015 06:51:44 »
The earth axis is at a 23 Degree tilt as noted by many sources, so at a 0 degree tilt my hypothesis is there would be no Coriolis effect. Sorry if you missed the NASA reference that from another reference point ie space  "there is no deflection and the motion is a straight line."
 
 

Offline Colin2B

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #7 on: 22/12/2015 11:04:48 »
The earth axis is at a 23 Degree tilt as noted by many sources, so at a 0 degree tilt my hypothesis is there would be no Coriolis effect.
The coriolis effect is completely independent of tilt and is due to the rotation of the earth.

Sorry if you missed the NASA reference that from another reference point ie space  "there is no deflection and the motion is a straight line."
We didn't miss the NASA reference, but I think you might be misunderstanding what they are saying given your comments about a missile on the equator and gravity.

A missile fired along the equator will be affected by gravity as it rises and falls, but there will be no coriolis effect.
A missile fired north to South or south to north will also be affected by gravity as it rises and falls. But it will also be affected by coriolis effect and veer to the right - northern hemisphere - as seen by an observer on earth (but not by an observer from space who will see a straight line).

I think you need to reread the NASA reference and perhaps a few other descriptions. It's not an easy one to grasp and many people are confused by it. But I can assure you it has nothing to do with the tilt or gravity.


Edit: I've thought of a demo you can do. Take a globe, a ball will do, and a felt tip. Put the pen on the equator and while rotating the ball (so points on equator move to your right) move the pen North in a straight line - as if viewed from space. Look at the pen line, while it ends at the North Pole in front of you, the start point on the equator is now off to the right possibly behind the ball. The line will start running almost parallel to the equator then turn right towards the pole, and yet viewed 'from space' you saw a straight line upwards.
« Last Edit: 22/12/2015 11:55:45 by Colin2B »
 

Offline A Davis

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #8 on: 28/12/2015 00:34:56 »
Getting back to basics if there are two degrees of spin there will always be a third , the coriolis effect, another degree of spin that will occur on it,s own. I don,t see how a space ship has two degrees of spin. I can count only one due to the earhts rotation, if it spins as it takes off, then there will be a third.
 

Offline Colin2B

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #9 on: 29/12/2015 14:23:21 »
.... I don,t see how a space ship has two degrees of spin. I can count only one due to the earth's rotation, if it spins as it takes off, then there will be a third.
The OP has asked a question about a missile fired from Earth. This will take a curved course, from Earth frame of reference, due only to the earth's rotation whether the missile spins or not.
What you seem to be alluding to is torque induced precession. This will not occur in this case, even if the missile spins, because from an inertial reference frame the missile is following a straight line.
 

Offline mrsmith2211

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #10 on: 10/01/2016 23:58:01 »
So the question in my mind is it an observed effect or an actual effect ie frame of reference issue. My previous hypothesis is that is it is an observed effect due to the fact that the earth has a tilted axis, and due to earths rotation the target has moved between firing of missile and landing of missile, unles I misinterpret the previous post it is a frame of reference issue.
 

Offline Space Flow

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #11 on: 11/01/2016 01:48:04 »
My previous hypothesis is that is it is an observed effect due to the fact that the earth has a tilted axis, and due to earths rotation the target has moved between firing of missile and landing of missile, unles I misinterpret the previous post it is a frame of reference issue.
As long as you leave the tilt of the axis out of the influences involved, then both of those descriptions are accurate and in no way contradictory or exclusive of the other.
They both accurately describe the same thing.
Axial tilt has no influence.
 

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Re: Is the Coriolis effect, as applied to missiles, wrong?
« Reply #11 on: 11/01/2016 01:48:04 »

 

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