Which airplane will cover more ground distance?
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I think you are all too bored just to admit they both cover the same distance.
Anyway, why is nobody considering their relative bearings? -Earth spinning under you will modify the ground miles you fly in a given time period at a constant speed.
Regards
Anyway, why is nobody considering their relative bearings? -Earth spinning under you will modify the ground miles you fly in a given time period at a constant speed.
Regards
It's true that the Earth is spinning, but this does not change the result.
In what we on the ground would experience as still air conditions, the air is spinning at the same speed as the Earth. If it were not, we would have a wind speed of about 1000 knots at the Equator. This would drastically rearrange most of the rain forrests and the monkeys would need much stronger grips!
The question specifies that both aircraft are flying at the same TAS. This means that they have the same speed relative to the atmosphere (which as we have observed is spinning at the same speed as the Earth).
So the fact that the Earth is spinning does not change the ground distance flown.
In what we on the ground would experience as still air conditions, the air is spinning at the same speed as the Earth. If it were not, we would have a wind speed of about 1000 knots at the Equator. This would drastically rearrange most of the rain forrests and the monkeys would need much stronger grips!
The question specifies that both aircraft are flying at the same TAS. This means that they have the same speed relative to the atmosphere (which as we have observed is spinning at the same speed as the Earth).
So the fact that the Earth is spinning does not change the ground distance flown.
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So which two aircraft are capable at matching speeds at these two very different levels, and when was the last time there was nil wind all the way up?
What utter nonsense. You don't happen to write the questions for the CAA do you?
What utter nonsense. You don't happen to write the questions for the CAA do you?
What utter nonsense. You don't happen to write the questions for the CAA do you?
I did not write the OP's question and I do not write questions for the CAA.
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'twas aimed at the OP, as this is the sort of nonsense theoretical question that the CAA have in their papers.
Perhaps a misplaced rant after a few beers at the end of the week
However, this is purely a geometry question, as the parameters would be impossible to create in real life, so it has absolutely nothing to do with flying a plane.
How did the aircraft get to 40,000'? It obviously climbed, which reduces groundspeed.
Why not ask the same question that if an aircraft at 40,000' could match the speed of the international space station, which covers more ground?
Or if I dig a tunnel 500' below the ground, and flew through that at the same speed as the aircraft at 2000'? Who covers more ground then?
These are all very nice questions if you like a maths problem to solve, perhaps something to do on long flights between you and the captain, but nothing to do with flying a plane.
Perhaps a misplaced rant after a few beers at the end of the week
However, this is purely a geometry question, as the parameters would be impossible to create in real life, so it has absolutely nothing to do with flying a plane.
How did the aircraft get to 40,000'? It obviously climbed, which reduces groundspeed.
Why not ask the same question that if an aircraft at 40,000' could match the speed of the international space station, which covers more ground?
Or if I dig a tunnel 500' below the ground, and flew through that at the same speed as the aircraft at 2000'? Who covers more ground then?
These are all very nice questions if you like a maths problem to solve, perhaps something to do on long flights between you and the captain, but nothing to do with flying a plane.
Last edited by RTN11; 12th Jan 2014 at 12:36.
As RTN11 (and I in an earlier post) have said, this question is concerned solely with geometry. Had it include IAS, this would have introduced the added complication of the relationship between the IAS/TAS ratio and the air density. This in turn would have required the inclusion of specific altitudes, and/or atmospheric conditions to enable the actual IAS/TAS ratios to be calculated. The overall result would have been the conversion of a relatively simple question into a much more complicated one. As a number of the posts in this thread indicate, the simple geometric question was too complex for some reader.
Virtually all fields of study have employed the practice of posing questions and seeking to deduce the answers to these questions. The questions are often quite abstract and in most cases include various simplifying assumptions. The question posed by the OP in this thread is simply one example of such a question.
The fact that a question is purely theoretical does not make it unworthy of inclusion in pprune. Consideration of this type of question is often the most effective route to developing a thorough understanding of matters. pprune would be a much poorer site if we were to exclude theoretical questions.
For those who dislike purely theoretical questions I would suggest you adopt what I call the Pilchard Principle. I hate tinned pilchards. The very though of them makes me feel quite unwell to the point that I want to heave. I'm actually feeling a bit queasy just writing about them. But this poses no real problem for me. I simply avoid having anything to do with tinned pilchards. The same method would be just as effective when dealing with purely theoretical questions. If you don't like them don't read them.
Virtually all fields of study have employed the practice of posing questions and seeking to deduce the answers to these questions. The questions are often quite abstract and in most cases include various simplifying assumptions. The question posed by the OP in this thread is simply one example of such a question.
The fact that a question is purely theoretical does not make it unworthy of inclusion in pprune. Consideration of this type of question is often the most effective route to developing a thorough understanding of matters. pprune would be a much poorer site if we were to exclude theoretical questions.
For those who dislike purely theoretical questions I would suggest you adopt what I call the Pilchard Principle. I hate tinned pilchards. The very though of them makes me feel quite unwell to the point that I want to heave. I'm actually feeling a bit queasy just writing about them. But this poses no real problem for me. I simply avoid having anything to do with tinned pilchards. The same method would be just as effective when dealing with purely theoretical questions. If you don't like them don't read them.
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Sorry if my tone was a little off. I realise that theoretical questions have their place, I just find it amusing how many posters on here are unsure of the correct answer, or how to work it out, when it's a very simple shape/curve based question, with very little relevance to day to day operations.
If you're working in GPS mapping or satellite positioning, you need a very thorough understanding of such basic principles, but as has been demonstrated by some of the responses on here, many pilots do not.
If you're working in GPS mapping or satellite positioning, you need a very thorough understanding of such basic principles, but as has been demonstrated by some of the responses on here, many pilots do not.
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Well I posted this question here because it was asked in an interview.
Thanks Keith Williams for your detailed answers. I also believe that theoretical questions are important.
Thanks everyone else, for answering.
To people who do not want to answer such questions: simply ignore the thread!
Thanks Keith Williams for your detailed answers. I also believe that theoretical questions are important.
Thanks everyone else, for answering.
To people who do not want to answer such questions: simply ignore the thread!
