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Will it take off ?!

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Will it take off ?!

Of course it will you muppet, dont you know physics ?
39
35%
Not a chance in hell it will get airborne !
66
59%
Help, my brain hurts !?
7
6%
 
Total votes: 112

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ONMEHEADSON
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Post by ONMEHEADSON »

By Unscimes. This is all very interesting, although irrelevant to the original question posed by Zeus.

Although as you have stated that the wheels are freewheeling, and are not mechanically attached to anything, I assume that under the original question, you now accept that the plane will take off.

Is this true - are you now a 'flier'?

And are you now working on a different problem?
No it is not irrelevant Unscimes. It is the most relevant issue for me.
Is the plane allowed to move forward? Yes or No?
If yes - then the conveyer doesn´t have a tracking system that tracks the aircrafts speed and negates it.
By Jez. The distance is irrelevant, it could be half a mile or 20 miles, it was just as an example to give perspective.
Yes the distance is irrelevant Jez. I agree. But the original question indicates that the aircraft wont move forward as it´s speed is negated by the control system.

I realise I am repeating myself now - but please, please tell me you understand what i´m saying.

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ONMEHEADSON
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Post by ONMEHEADSON »

Unscimes, you dont understand where I´m coming from?
OK Fair game you dont understand me. What more can I do?

But, let me say - you earlier wrote this:
"The 'wheels', as a whole, must move at the same speed as the plane, as they are attached"

You are confused about the question, no doubt about it.

I agree, we shouldn´t argue (fellow members and all that)

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uncsimes
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Post by uncsimes »

ONMEHEADSON wrote:
By Unscimes. This is all very interesting, although irrelevant to the original question posed by Zeus.

Although as you have stated that the wheels are freewheeling, and are not mechanically attached to anything, I assume that under the original question, you now accept that the plane will take off.

Is this true - are you now a 'flier'?

And are you now working on a different problem?
No it is not irrelevant Unscimes. It is the most relevant issue for me.
Is the plane allowed to move forward? Yes or No?
If yes - then the conveyer doesn´t have a tracking system that tracks the aircrafts speed and negates it.
By Jez. The distance is irrelevant, it could be half a mile or 20 miles, it was just as an example to give perspective.
Yes the distance is irrelevant Jez. I agree. But the original question indicates that the aircraft wont move forward as it´s speed is negated by the control system.

I realise I am repeating myself now - but please, please tell me you understand what i´m saying.
but it doesn't say that the tracking mechanism NEGATES the speed, it says it MATCHES it. They are totally different concepts.

To negate the speed, there would have to be some mechanism applying rearward force to the plane - which there isn't (because of the freewheel as you so elegantly described using your Shrek example) unless we are assuming that this mechanism is a steel cable attached to a big mass somehere behind the plane.

To match the speed (which is what it says), you just need a radar speed gun and some software to adjust the speed of the conveyor motor to cause movement of the conveyor at the relevant speed in the opposite direction.

I understand exactly where you're coming from in that you are making up your own question to match your statement that the plane won't move.

However, if you read the question literally, it takes off.
Last edited by uncsimes on 27 Feb 2006, 11:34, edited 1 time in total.

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Zeus
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Post by Zeus »

ONMEHEADSON wrote:
No it is not irrelevant Unscimes. It is the most relevant issue for me.
Is the plane allowed to move forward? Yes or No?
If yes - then the conveyer doesn´t have a tracking system that tracks the aircrafts speed and negates it.
I think this is where your argument is falling. The conveyors theoretical tracking device is attempting to negate the forward motion of the aircraft, but is unable to do so due to its minimal effect on the airframe.

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uncsimes
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Post by uncsimes »

ONMEHEADSON wrote:Unscimes, you dont understand where I´m coming from?
OK Fair game you dont understand me. What more can I do?

But, let me say - you earlier wrote this:
"The 'wheels', as a whole, must move at the same speed as the plane, as they are attached"

You are confused about the question, no doubt about it.

I agree, we shouldn´t argue (fellow members and all that)
I'm honestly not trying to be 'funny' or 'difficult' about this, but I don't see what my statement (which I have proved, albeit having to define what I mean in more detail) about the wheels as a whole having to move at the same speed as the aircraft, has to do with the original question. This says that the conveyors control mechanism matches the speed of the aircraft - it doesn't mention rotational speed, wheels, negating or anything else.

I respect the fact that you are prepared to argue your corner, but just think that you're reading things into the question that arent there.

If you read the question that the conveyor mechanism exerts a force which negates the force of the engines, then I see where you are coming from. The plane will not move under those circumstances. If that's what you want me to say, well then I've said it. And I believe it - I'm not just saying it for the sake of stopping the debate.

However, I don't see where the question says that.

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Post by JaseC »

uncsimes wrote: but it doesn't say that the tracking mechanism NEGATES the speed, it says it MATCHES it. They are totally different concepts.

To negate the speed, there would have to be some mechanism applying rearward force to the plane - which there isn't (because of the freewheel as you so elegantly described using your Shrek example) unless we are assuming that this mechanism is a steel cable attached to a big mass somehere behind the plane.

To match the speed (which is what it says), you just need a radar speed gun and some software to adjust the speed of the conveyor motor to cause movement of the conveyor at the relevant speed in the opposite direction.

I understand exactly where you're coming from in that you are making up your own question to match your statement that the plane won't move.

However, if you read the question literally, it takes off.
Uncsimes is bang on. Coming from an initial stand point of it not getting airborne - I also thought the aircraft would remain stationary.

It does not of course as the wheels will turn and the aircrat moves forward from the engines thrust.

If the conveyor negated the speed it would have to latch hold of the aircrafts body in someway to counteract the thrust. If it just matches the speed then it moves backwards and spins the wheels which are free to rotate and can not transmit a retarding force to the airframe.

I have my own theories on length of take of roll and time to getting airborne - but these are largley irrelevant as the fact is the plane moves forward and takes off.

Incidentally if the conveyor belt is not long enough (or close enough to the ground) then the aircraft will fall off and maybe plough into the ground - which would mean no take off. But that is a different matter. :wink:

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Post by Zeus »

JaseC wrote:
uncsimes wrote: but it doesn't say that the tracking mechanism NEGATES the speed, it says it MATCHES it. They are totally different concepts.

To negate the speed, there would have to be some mechanism applying rearward force to the plane - which there isn't (because of the freewheel as you so elegantly described using your Shrek example) unless we are assuming that this mechanism is a steel cable attached to a big mass somehere behind the plane.

To match the speed (which is what it says), you just need a radar speed gun and some software to adjust the speed of the conveyor motor to cause movement of the conveyor at the relevant speed in the opposite direction.

I understand exactly where you're coming from in that you are making up your own question to match your statement that the plane won't move.

However, if you read the question literally, it takes off.
Uncsimes is bang on. Coming from an initial stand point of it not getting airborne - I also thought the aircraft would remain stationary.

It does not of course as the wheels will turn and the aircrat moves forward from the engines thrust.

If the conveyor negated the speed it would have to latch hold of the aircrafts body in someway to counteract the thrust. If it just matches the speed then it moves backwards and spins the wheels which are free to rotate and can not transmit a retarding force to the airframe.

I have my own theories on length of take of roll and time to getting airborne - but these are largley irrelevant as the fact is the plane moves forward and takes off.

Incidentally if the conveyor belt is not long enough (or close enough to the ground) then the aircraft will fall off and maybe plough into the ground - which would mean no take off. But that is a different matter. :wink:
JasC

Just wondering, is this new standpoint your own viewpoint or the collective viewpoint of the pilots you work with ? Have you managed to persuade them or are you now a lonely voice of dissention ?

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djwhew
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Post by djwhew »

ive just asked my 10 year old boy and he recons foget the wheels the thrust of the jet engine would move it forward the wheels just hold it in place??

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Post by Alchemist »

ONMEHEADSON wrote:
By Unscimes. This is all very interesting, although irrelevant to the original question posed by Zeus.

Although as you have stated that the wheels are freewheeling, and are not mechanically attached to anything, I assume that under the original question, you now accept that the plane will take off.

Is this true - are you now a 'flier'?

And are you now working on a different problem?
No it is not irrelevant Unscimes. It is the most relevant issue for me.
Is the plane allowed to move forward? Yes or No?
If yes - then the conveyer doesn´t have a tracking system that tracks the aircrafts speed and negates it.
By Jez. The distance is irrelevant, it could be half a mile or 20 miles, it was just as an example to give perspective.
Yes the distance is irrelevant Jez. I agree. But the original question indicates that the aircraft wont move forward as it´s speed is negated by the control system.

I realise I am repeating myself now - but please, please tell me you understand what i´m saying.


OMHS


Please take a few moments to consider the follwoing arguement

Your left hand is resting on your right hand. If your left hand moved to the left, your right hand moves to the right. Your brain has a control system that tracks your left hand speed and tunes the speed of your right hand to be exactly the same, but in the opposite direction. There is no wind.

You start to move your left hand......


Please tell me what happens next.

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Fuzzy Logic
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Post by Fuzzy Logic »

Alchemist wrote: OMHS


Please take a few moments to consider the follwoing arguement

Your left hand is resting on your right hand. If your left hand moved to the left, your right hand moves to the right. Your brain has a control system that tracks your left hand speed and tunes the speed of your right hand to be exactly the same, but in the opposite direction. There is no wind.

You start to move your left hand......


Please tell me what happens next.
reckon you'll be forced to say 'Just like that'

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JaseC
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Post by JaseC »

Zeus wrote:
JaseC wrote:
uncsimes wrote: but it doesn't say that the tracking mechanism NEGATES the speed, it says it MATCHES it. They are totally different concepts.

To negate the speed, there would have to be some mechanism applying rearward force to the plane - which there isn't (because of the freewheel as you so elegantly described using your Shrek example) unless we are assuming that this mechanism is a steel cable attached to a big mass somehere behind the plane.

To match the speed (which is what it says), you just need a radar speed gun and some software to adjust the speed of the conveyor motor to cause movement of the conveyor at the relevant speed in the opposite direction.

I understand exactly where you're coming from in that you are making up your own question to match your statement that the plane won't move.

However, if you read the question literally, it takes off.
Uncsimes is bang on. Coming from an initial stand point of it not getting airborne - I also thought the aircraft would remain stationary.

It does not of course as the wheels will turn and the aircrat moves forward from the engines thrust.

If the conveyor negated the speed it would have to latch hold of the aircrafts body in someway to counteract the thrust. If it just matches the speed then it moves backwards and spins the wheels which are free to rotate and can not transmit a retarding force to the airframe.

I have my own theories on length of take of roll and time to getting airborne - but these are largley irrelevant as the fact is the plane moves forward and takes off.

Incidentally if the conveyor belt is not long enough (or close enough to the ground) then the aircraft will fall off and maybe plough into the ground - which would mean no take off. But that is a different matter. :wink:
JasC

Just wondering, is this new standpoint your own viewpoint or the collective viewpoint of the pilots you work with ? Have you managed to persuade them or are you now a lonely voice of dissention ?
I am actually convincing them also!! Before you think about the question - the natural instinct is to say no because it seems that the aircraft will have no forward speed hence no lift.

However, this is not the case when you look more closely. I still think there is an element of "question interpretation" in there though!

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Post by Alchemist »

700........ Gone a bit quiet!

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Fuzzy Logic
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Post by Fuzzy Logic »

Alchemist wrote:700........ Gone a bit quiet!
Yes it has, there be only the flight experiment to go. :-)

With this in mind, and whilst working through the whole will it or won't it. I came across this:
Richard Feynman wrote:
This problem is from Surely You're Joking, Mr. Feynman! by Richard Feynman.

You have an S-shaped lawn sprinkler-an S-shaped pipe on a pivot-and the water squirts out at right angles to the axis and makes it spin in a certain direction. Everybody knows which way it goes around; it backs away from the outgoing water. Now the question is this: If you had a lake, or swimming pool-a big supply of water-and you put the sprinkler completely under water, and sucked water in, instead of squirting it out, which way would it turn? Would it turn the same way as it does when you squirt water out into the air, or would it turn the other way?
quickly runs away whistling

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The Jezster
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Post by The Jezster »

YOU bustard!!!

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Billy Whiz
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Post by Billy Whiz »

To save everyone's time, this one has already been debated on the following "Advanced Physics Forum" (of which I am now a member :wink: )

http://www.advancedphysics.org/forum/ar ... t-168.html

What we need now is a new physics problem that can't be accessed on the web!

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The Jezster
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Post by The Jezster »

Billy, without having looked at the forum youve linked to, my immediate reaction is that it will not turn. Is this correct?

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Post by Fuzzy Logic »

The Jezster wrote:Billy, without having looked at the forum youve linked to, my immediate reaction is that it will not turn. Is this correct?
I take it the discussion we had on this doesn't count then :wink:

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uncsimes
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Post by uncsimes »

The sprinker one sounds like it would need some knowledge of fluid dynamics to work out. I did do some fluid dynamics at Uni but that was a long time ago and I've never had to use it in practice (did work as an engineer for a while - working on stresses and forces in turbine blades and generator rotor's (particularly 'End Bells', much to our amusement at the time!) before switching to accountancy).

I reckon that once the water is flowing, there will be no rotational force or torque to move it in any direction, but would struggle to prove it. As for what happens when you first turn the water on... No idea. I suspect that it must move in some direction as there must be some initial torque - common sense says that it would move in the opposite direction when sucking in to when it is blowing out???

Doubt too many here would know too much about fluid dynamics (without looking it up anyway!) so reckon it probably won't take off.





:wink:

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Post by murf »

I was always puzzled over whether water rotated in the opposite direction in the southern hemisphere when going down the plughole. Thankfully that was solved for me by a TV programme called The Simpsons.

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Post by Billy Whiz »

No one's posted on this thread for 24 hours! Where's everybody gone? :shock:

So what does happen when an unstoppable force hits an immoveable object? :lol:

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Post by djwhew »

you get divorced

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Post by Dr. Pepper »

So will it take off or not?

Video?

Is Del Horno injured???

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Re: Will it take off ?!

Post by AKNel1 »

Zeus wrote:Ok, last night whilst in the pub I was arguing with a mate over a problem that his physics lecturer had set him. By the end of the evening, neither of us had persuaded the other that he was right, but had managed to confuse about twenty people who we explained it to. Now before you vote or add your comments, just take a moment to think about it !

The problem goes like this:
An aircraft is standing on a runway that can move (a conveyor belt). The aircraft moves in one direction, while the conveyor moves in the opposite direction. This conveyor has a control system that tracks the aircraft's speed and tunes the speed of the conveyor to be exactly the same, but in the opposite direction. There is no wind. The pilot begins to add thrust to the engines...



The question is:

Will the plane take off or not?

I voted it takes off because a/ the question states that the plane 'moves' in the opposite direction thereby creating wind thereby creating lift

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Post by DixieDean »

Coor you've raked up a right can of worms there mate :wink:

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The Jezster
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Post by The Jezster »

I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..
I must not come back to this thread..

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Post by Madchester »

i thought this thread had been locked!

p.s. no, it won't take off :wink:

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murf
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Post by murf »

This thread is over.

All right minded people know it takes off and surely nobody else wants to embarass themselves further..............

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Post by snout »

murf wrote:This thread is over.

All right minded people know it takes off and surely nobody else wants to embarass themselves further..............
What do the left-minded people think? :wink:

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Post by DixieDean »

AKNel1... do you know what you have done!!!!...


I'm off to hide under a conveyor belt somewhere :lol:

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Post by Madchester »

DixieDean wrote:
I'm off to hide under a conveyor belt somewhere :lol:
don't hide under the one which the plane will be using to try to take off... because it'll fall off onto your head!

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