What causes the change in velocity from pole to equator on Earth?

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Discussion Overview

The discussion revolves around the change in velocity experienced by a person moving from the pole to the equator on Earth due to the planet's rotation. Participants explore the concepts of tangential velocity, acceleration, and the effects of Earth's rotation on movement, with a focus on theoretical and conceptual understanding.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant notes that a person at the pole has no tangential velocity due to Earth's rotation, while at the equator, the tangential velocity is approximately 1,670 kph.
  • Another participant introduces a hypothetical scenario involving free fall and skating on an ice surface to illustrate the concept of acceleration as the ground moves beneath a stationary observer.
  • A third participant reiterates the initial point about the change in velocity and discusses the influence of the Coriolis force and the effect of the Earth's rotation on an airplane flying from the pole to the equator, suggesting that the airplane experiences a sidewind that contributes to its eastward acceleration.
  • One participant expresses gratitude for the explanations provided, indicating a personal understanding of the topic.

Areas of Agreement / Disagreement

The discussion includes multiple viewpoints regarding the mechanisms of acceleration and the effects of Earth's rotation, with no consensus reached on a singular explanation.

Contextual Notes

Participants mention the Coriolis force and the influence of local wind and weather, but these factors remain unresolved in terms of their specific contributions to the change in velocity.

papernuke
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Assume there's a person standing at the pole of the earth. When the Earth rotates, he/she has no tangential velocity because the person is at the pole.
Now if the person were to take a trip by plane and land at the equator, the person would now have a fairly large velocity because the equator's tangential velocity is quite high.
What provides the acceleration that that changes the person's velocity from zero at the pole to 1,670 kph at the equator?


source for 1,670: http://geography.about.com/library/faq/blqzEarth'spin.htm
 
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Why the Earth does - and the engines in the means of transportation.

Consider, you are in free fall above an airless spherical World composed entirely of ice and you are wearing ice-skates.
The world is turning below you. The ground gets closer - your feet touch the ground - the world keeps turning under you.

From your POV, you are now skating very fast across the surface.
Turn your skates and you can slide to a "stop" - now you are going at the same speed as the surface under you ... where did the acceleration come from?
 
Last edited:
papernuke said:
Assume there's a person standing at the pole of the earth. When the Earth rotates, he/she has no tangential velocity because the person is at the pole.
Now if the person were to take a trip by plane and land at the equator, the person would now have a fairly large velocity because the equator's tangential velocity is quite high.
What provides the acceleration that that changes the person's velocity from zero at the pole to 1,670 kph at the equator?source for 1,670: http://geography.about.com/library/faq/blqzEarth'spin.htm

If we ignore variation from the local wind and weather on the surface of the earth, the air at the equator is moving at 1670 kph relative to the air at the north pole. So as the airplane flies southwards, it experiences a sidewind blowing from the west that accelerates it in an eastwards direction.

If you were walking south from the north pole, with every single step you'd be putting your foot down on a patch of Earth that is moving ever so slightly faster to the east than where your foot had been. It's not much at each step, but it's enough to add up to 1670 kph over the 20,000,000 or so steps between pole and equator.

You might want to google for "Coriolis force".
 
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Thank you both for the explanations!
I understand it now
 

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