# Flying time

Discussion in 'Physics & Math' started by Saint, Jun 27, 2017.

1. ### SaintValued Senior Member

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3,519
We know that the earth is rotating from west to east.
Let's say I fly an aeroplane from London to New York and vise versa,
with the same average speed,
the time taken for:
1) London to NY, T1
2) NY to London, T2.

Should it be T1<T2 ?

3. ### sideshowbobSorry, wrong number.Valued Senior Member

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The atmosphere is rotating with the earth.

5. ### billvonValued Senior Member

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Speed of the Earth doesn't matter. Speed of the winds near the airplane do matter. JFK to London is generally faster due to prevailing winds.

7. ### gmilamValued Senior Member

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Friend of mine is a retired pilot. I asked him why it generally took me longer to fly from London to NY than it did the other direction. He said it was because of the headwinds.

8. ### sweetpeaValued Senior Member

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How does the jet stream affect flights?
https://en.wikipedia.org/wiki/Jet_stream
My bold.

http://www.metoffice.gov.uk/learning/wind/what-is-the-jet-stream
My bold.

9. ### SaintValued Senior Member

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Do you mean the atmosphere is moving together with the ground when earth rotating?

10. ### The GodValued Senior Member

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Yes. If not then what?

Earth rotation speed (equatorial) on its axis is around 500 meters per second , so if the atmosphere is not moving with the earth, you will be seeing clouds wheezing past you at that speed. Birds will do cross country and cross continent visits just by floating in the sky. A para glider will have to take a ship back home. All sort of crazy things would happen.

11. ### dumbest man on earthReal Eyes Realize Real LiesValued Senior Member

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...yes...
In concurrence with sideshowbob's Post #2 : "The atmosphere is rotating with the earth."

12. ### ajantaRegistered Senior Member

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611
The Earth’s rotation does not affect travel time. When a child tosses a ball up and down in a train moving at 100 kilometres an hour, the ball is not displaced because of the train’s motion. Similarly, aircraft fly in an atmosphere that moves with the Earth. What affects the duration of flight are winds. They can be very strong and generally blow from the west in Canadian latitudes. In fact, westerly winds can be so strong that the duration of a transcontinental flight from Vancouver to Toronto can be about 30 minutes less than a flight from Toronto to Vancouver.

https://www.msnucleus.org/membership/html/jh/earth/atmosphere/lesson4/atmosphere4a.html

Last edited: Jun 28, 2017
13. ### SaintValued Senior Member

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3,519
Which mean the airplane on the air is pulled by the gravity, correct?

14. ### ajantaRegistered Senior Member

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Gravity helps create lift for paper airplanes. The force of gravity that pulls objects toward the Earth. Lift is the force that pushes an aircraft into the air. When paper airplanes are thrown up, gravity pulls them down. This movement causes a difference of air pressure on the airplane wings, which then causes lift. Bernoulli's Principle explains how a difference of air pressure is caused due to air moving faster on top of the wings than on bottom. It is because of gravity that paper airplanes are able to produce this difference and glide!

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16. ### SaintValued Senior Member

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3,519
When an airplane is flying, what is its relative velocity to the ground?
Do you model the ground as static?
But indeed the earth is rotating

17. ### SaintValued Senior Member

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Speed of sound = 1235 km/hr

You see, a point on the ground, when look from outer space, has such a supersonic speed,
the plane is in the air, the direction it flies must have effect on the time traveled between two points.

18. ### James RJust this guy, you know?Staff Member

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And prevailing winds are, in large part, due to rotation of the Earth, combined with the locations of land masses compared to oceans, and a few other factors.

19. ### SaintValued Senior Member

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Do we apply Newtonian Law to analyze this problem?

20. ### billvonValued Senior Member

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Nope. It doesn't care.

Do this experiment. Use the bathroom on an aircraft flying at 550mph. Does your urine get plastered to the side of the restroom? Does the 550mph wind blast it to mist? Nope. Things work like they always do.

How fast you are going doesn't matter. What matters to an airplane is how fast it is going relative to the air outside.

21. ### SaintValued Senior Member

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When you are in the plane, the relative velocity between you and the plane is basically zero.
But the plan is on the air, it is not connected to the ground by any mean.
Gravity is pulling the plane toward the center of the earth.
But the plane is flying, and the earth is rotating,
it must be a complicated system of motion.
How can we just treat the earth as static and flat, and consider the plane is in motion only?

22. ### The GodValued Senior Member

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The mass of the earth is of the order of 10^24 kgs, that of atmosphere is 10^18 kgs and that of jumbo Airbus A380 is around 10^5 kgs....

For a spinning atmosphere of 10^18 kgs, carrying a comparatively insignificant mass of 10^5 kgs along is not an issue.

23. ### SaintValued Senior Member

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Is there no relativity between the earth and the plane?