Coriolis acceleration of a projectile launched at the equator

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Discussion Overview

The discussion revolves around the Coriolis acceleration experienced by a projectile launched from the equator at a 45-degree angle relative to the surface. Participants explore the implications of the launch angle on the Coriolis effect, particularly in the context of long-range ballistic travel.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the Coriolis acceleration is truly zero at the equator when a projectile is launched at an angle, suggesting that the velocity vector's orientation could result in a non-zero Coriolis effect.
  • Another participant reiterates that Coriolis acceleration is zero at the equator only if the launch angle is zero, implying that any angle could introduce a Coriolis effect.
  • A later reply references the standard formula for calculating Coriolis acceleration, indicating that it supports the idea of a non-zero effect when the velocity vector is not parallel to the surface.
  • One participant provides external links to resources on exterior ballistics, although these do not fully address the specific question raised about Coriolis acceleration.
  • Another participant cites a specific example of projectile deflection due to Coriolis effects, noting the directional influence on shots fired north or south at a significant range.

Areas of Agreement / Disagreement

Participants express differing views on whether Coriolis acceleration can be considered zero at the equator when launching at an angle. There is no consensus on the implications of the launch angle for the Coriolis effect.

Contextual Notes

The discussion highlights the complexity of the Coriolis effect in relation to projectile motion, with participants noting assumptions about launch angles and the dependence on the velocity vector's orientation.

jk185
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I have a question about the Coriolis acceleration experienced by a projectile launched from the surface of a rotating body.

Say a ball is launched at 45 degree angle relative to the surface at some initial velocity v0. Let's further specify that the ball is launched due north from the equator (i.e. latitude = 0). I want to calculate the Coriolis acceleration (and its x, y, z components) that is experienced by the ball. Since the launch occurs at the equator, most would say that the Coriolis acceleration is zero, but is this true? Isn't the Coriolis acceleration only 0 at the equator since the launch angle is assumed to be 0 (i.e. the motion is parallel to the surface), meaning the velocity vector is parallel to the rotational vector? If a ball is launched at some angle relative the surface, the velocity vector is no longer parallel to the surface, meaning that there should actually be a Coriolis acceleration that is experienced by the ball.

Also, I am particularly interested in long-range ballistic travel.

Is there something that I am missing here? I have looked everywhere for an answer to this question but haven't found anything that specifically addresses this question.

Any help is appreciated here. Thanks!
 
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jk185 said:
Isn't the Coriolis acceleration only 0 at the equator since the launch angle is assumed to be 0 (i.e. the motion is parallel to the surface), meaning the velocity vector is parallel to the rotational vector? If a ball is launched at some angle relative the surface, the velocity vector is no longer parallel to the surface, meaning that there should actually be a Coriolis acceleration that is experienced by the ball.
That seems to be what the standard formula for calculating the Coriolis acceleration ##a_C=2\vec{\Omega}\times\vec{v}## says, yes.
 
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https://www.eugeneleeslover.com/USNAVY/FC-APPENDIX-B-8IN-55.html said:
1652974773254.png
Look at the Latitude 0 section and the columns for a target at 0 degrees (North) or 180 degrees (South). Look at the row for 30,000 yard range. A shot at those angles is deflected 42 yards left (west) when firing north and 42 yards right (west) when firing south. This is presumably due to Coriolis acting on the arching shot.
 
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