photon
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and the site receives a small commission
Will it take off?
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OP
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Almost but not quite .... If the wheels do 'try' to move faster? then the belt will match their speed ..
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So, we can substitute bogies?
Ian D J
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Unless the jet engines generates so much thrust (opposable force) that the plane actually takes off like a rocket.
Then once it's in the air, the airflow around the wings does the rest and the jet engines can ease back.
Sorry if that has been brought up earlier.
Then once it's in the air, the airflow around the wings does the rest and the jet engines can ease back.
Sorry if that has been brought up earlier.
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I gave up reading after page 3 but GrittyShaker has the correct explanation I think...
in order to take off, plane must be moving forward on the conveyor belt.
in order to move forward on the conveyor belt, the wheels have to be moving faster than the speed of the conveyor belt
In order to move the wheels faster, plane's engine need to overcome the friction on the wheels...
in order to take off, plane must be moving forward on the conveyor belt.
in order to move forward on the conveyor belt, the wheels have to be moving faster than the speed of the conveyor belt
In order to move the wheels faster, plane's engine need to overcome the friction on the wheels...
It can if the plane isn't moving, but as soon as there is forward thrust from the engines the plane will move forwards (irrespective of the speed of the belt) and the wheels will then be spinning faster than the belt is moving.
If you imagine a person walking on a moving escalator, in the opposite direction. In order to stay in one spot they have to walk at the same speed as the escalator. If the person wants to move forwards, they need to walk faster, but you can counteract that by moving the escalator faster, because the person is driven by their legs, which are in contact with the escalator.
The same thing can't be said about the plane. It's not driven by anything that's in contact with the belt, so if the plane has forward thrust it will move forwards no matter what the belt is doing. But its wheels will be spinning faster than the belt. Physics dictate that.
So there.
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But if you read the OP the conveyor belt always matches the speed of the wheels
There is (almost) no friction within the wheel bearings / wheels, therefore the wheels cannot overcome the friction between the belt and the wheels.
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The speed of the conveyor will never successfully match the speed of the wheels, however well it's designed. It's impossible.
The fact that there is no (notable) friction in the wheel bearings, and that the belt is travelling in the opposite direction to the wheels immediately tells us that the wheels will be spinning faster than the belt.
Unless the belt is spinning in the same direction as the wheels, which is plausible, as the details of the argument have been changed a few times already. Is the conveyor belt still travelling in the opposite direction to the wheels?
The fact that there is no (notable) friction in the wheel bearings, and that the belt is travelling in the opposite direction to the wheels immediately tells us that the wheels will be spinning faster than the belt.
Unless the belt is spinning in the same direction as the wheels, which is plausible, as the details of the argument have been changed a few times already. Is the conveyor belt still travelling in the opposite direction to the wheels?
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Please read the OP I have never changed the details of 'the argument' perhaps you could reference a post to back up your claim!
may I suggest a bit of reading that may help you (and others) to understand the problem
Newtons third Law
Inertial frame of reference
Non-inertial
frame of reference
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My apologies I somehow missed this post :bonk:
This is another example of a bad analogy, but it's a good one to use
The problem here is that when you push your car you are exerting a force against the car i.e. pushing .. but you are also exerting a force against the ground .. i.e. you are stood on it whilst pushing the car ... equal and opposite reactions blah, blah, blah
The aircraft is never in a situation where it is being pushed this way (from the ground) The aircraft is pushed or pulled (arguably) through the air and this really does make a huge difference to the understanding of the problem!
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F1 cars are driven by the wheels. It doesn't matter if they are tested by that means or not. If they are on a conveyor belt with the wheels driving forwards, and the belt is moving backwards at the same speed, someone (like a plane's engine) can still push the car forwards on the belt, which will instantly make the car's wheels spin more quickly than the belt is. That's the reasoning. That is a fact. And there is no way of arguing with that, unless you are hoping to be completely incorrect. In which case, carry on.
The belt is travelling in the opposite direction to the wheels. Think of two cars facing in opposite directions. If one drives away at 20mph, it will be 20 miles away from the other car in one hour. If both cars drive away at 20mph, they will be 40 miles away from each other in one hour.
The belt can't match the speed of the wheels. They will both end up travelling at an infinite speed, which is impossible. It might try to keep up with the speed of the wheels, but very quickly either the belt or the wheels will collapse under the strain of trying to achieve the impossible.
The bit that seems to be getting ignored is that the plane is moving forwards on the belt. The belt can move at the same speed as the wheels as long as the plane is stationary, and the friction between the belt and wheels drags the wheels along at the same pace as it is moving. As soon as there is an outside force applied, such as the thrust from the plane's engines, which correlates with the wheels attached to it, the wheels will spin faster than the belt. They just will. It's impossible to deny that, but somehow you're managing to do so.
Is the belt moving in the same direction as the wheels, or in the reverse direction? A couple of your posts have suggested that the belt may be moving in the same direction,but I think it might be the way you've worded it.
Your second blue bit says that the wheels are moving at the same speed as the belt. This is in the opposite direction, yes? So the belt and wheels are moving at the same speed, but in the opposite direction? So when the plane moves forwards it increases the speed of the wheels. It's dead simple now. If the speed of the belt now increases, then so do the wheels of the plane as it's engines thrust it forwards. Then the belt increases its speed, and so on ad infinitum, until the undercarriage collapses in a ball of flame.
I'm not sure whether the rules have changed or not. I just think a few of your posts are badly worded.
It doesn't matter whether anyone reads those links or not. Most of it doesn't relate to this discussion. The only problem is that either; you don't understand the facts, you have worded the question wrongly from the start, or you are deliberately denying the facts to annoy me and everyone that agrees with me.
The belt is travelling in the opposite direction to the wheels. Think of two cars facing in opposite directions. If one drives away at 20mph, it will be 20 miles away from the other car in one hour. If both cars drive away at 20mph, they will be 40 miles away from each other in one hour.
The belt can't match the speed of the wheels. They will both end up travelling at an infinite speed, which is impossible. It might try to keep up with the speed of the wheels, but very quickly either the belt or the wheels will collapse under the strain of trying to achieve the impossible.
The bit that seems to be getting ignored is that the plane is moving forwards on the belt. The belt can move at the same speed as the wheels as long as the plane is stationary, and the friction between the belt and wheels drags the wheels along at the same pace as it is moving. As soon as there is an outside force applied, such as the thrust from the plane's engines, which correlates with the wheels attached to it, the wheels will spin faster than the belt. They just will. It's impossible to deny that, but somehow you're managing to do so.
Is the belt moving in the same direction as the wheels, or in the reverse direction? A couple of your posts have suggested that the belt may be moving in the same direction,but I think it might be the way you've worded it.
Your second blue bit says that the wheels are moving at the same speed as the belt. This is in the opposite direction, yes? So the belt and wheels are moving at the same speed, but in the opposite direction? So when the plane moves forwards it increases the speed of the wheels. It's dead simple now. If the speed of the belt now increases, then so do the wheels of the plane as it's engines thrust it forwards. Then the belt increases its speed, and so on ad infinitum, until the undercarriage collapses in a ball of flame.
I'm not sure whether the rules have changed or not. I just think a few of your posts are badly worded.
It doesn't matter whether anyone reads those links or not. Most of it doesn't relate to this discussion. The only problem is that either; you don't understand the facts, you have worded the question wrongly from the start, or you are deliberately denying the facts to annoy me and everyone that agrees with me.
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My apologies I somehow missed this post :bonk:
This is another example of a bad analogy, but it's a good one to use
The problem here is that when you push your car you are exerting a force against the car i.e. pushing .. but you are also exerting a force against the ground .. i.e. you are stood on it whilst pushing the car ... equal and opposite reactions blah, blah, blah
The aircraft is never in a situation where it is being pushed this way (from the ground) The aircraft is pushed or pulled (arguably) through the air and this really does make a huge difference to the understanding of the problem!
Ah, I don't think you understand your own argument.
It is an absolutely perfect analogy to use, as the forces are almost identical.
Why is the force against the ground any different to the force that the plane's engine is exerting? When the conveyor belt moves does it move the air with it? If a long tow rope was attached to the plane, and its engines weren't used, would it make a blind bit of difference? It wouldn't. The conveyor would move backwards, which would move the plane's wheels forwards. Then whatever is towing the plane would drive forwards, and the plane would move forwards, which would make the wheels spin more quickly.
Can you explain why me pushing my car from a static position on the ground is any different to a planes engines pushing moving air against static air behind it? There is no difference, as far as this discussion is concerned.
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that sounds right, pretty sure i have said the same thing multiple times in this thread.F1 cars are driven by the wheels. It doesn't matter if they are tested by that means or not. If they are on a conveyor belt with the wheels driving forwards, and the belt is moving backwards at the same speed, someone (like a plane's engine) can still push the car forwards on the belt, which will instantly make the car's wheels spin more quickly than the belt is. That's the reasoning. That is a fact. And there is no way of arguing with that, unless you are hoping to be completely incorrect. In which case, carry on.
The belt is travelling in the opposite direction to the wheels. Think of two cars facing in opposite directions. If one drives away at 20mph, it will be 20 miles away from the other car in one hour. If both cars drive away at 20mph, they will be 40 miles away from each other in one hour.
The belt can't match the speed of the wheels. They will both end up travelling at an infinite speed, which is impossible. It might try to keep up with the speed of the wheels, but very quickly either the belt or the wheels will collapse under the strain of trying to achieve the impossible.
The bit that seems to be getting ignored is that the plane is moving forwards on the belt. The belt can move at the same speed as the wheels as long as the plane is stationary, and the friction between the belt and wheels drags the wheels along at the same pace as it is moving. As soon as there is an outside force applied, such as the thrust from the plane's engines, which correlates with the wheels attached to it, the wheels will spin faster than the belt. They just will. It's impossible to deny that, but somehow you're managing to do so.
Is the belt moving in the same direction as the wheels, or in the reverse direction? A couple of your posts have suggested that the belt may be moving in the same direction,but I think it might be the way you've worded it.
Your second blue bit says that the wheels are moving at the same speed as the belt. This is in the opposite direction, yes? So the belt and wheels are moving at the same speed, but in the opposite direction? So when the plane moves forwards it increases the speed of the wheels. It's dead simple now. If the speed of the belt now increases, then so do the wheels of the plane as it's engines thrust it forwards. Then the belt increases its speed, and so on ad infinitum, until the undercarriage collapses in a ball of flame.
I'm not sure whether the rules have changed or not. I just think a few of your posts are badly worded.
It doesn't matter whether anyone reads those links or not. Most of it doesn't relate to this discussion. The only problem is that either; you don't understand the facts, you have worded the question wrongly from the start, or you are deliberately denying the facts to annoy me and everyone that agrees with me.
i am getting fed up with loads of people saying the same thing over and over so i am now going to unsubscribe and bow out.
have fun all!
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Sorry. You probably have said the same, but it's been going on forever, so I've forgotten a lot of it.How did that plane in your avatar take off? Are its wheels intact?
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F1 cars are driven by the wheels. It doesn't matter if they are tested by that means or not. If they are on a conveyor belt with the wheels driving forwards, and the belt is moving backwards at the same speed, someone (like a plane's engine) can still push the car forwards on the belt, which will instantly make the car's wheels spin more quickly than the belt is. That's the reasoning. That is a fact. And there is no way of arguing with that, unless you are hoping to be completely incorrect. In which case, carry on.
But you said that it was impossible for the conveyor to match the speed of the wheels :shrug:
The belt is travelling in the opposite direction to the wheels. Think of two cars facing in opposite directions. If one drives away at 20mph, it will be 20 miles away from the other car in one hour. If both cars drive away at 20mph, they will be 40 miles away from each other in one hour.
Correct! but each car has only travelled 20 miles ... so what's your point i.e. 20mph not 40 mph
The belt can't match the speed of the wheels. They will both end up travelling at an infinite speed, which is impossible. It might try to keep up with the speed of the wheels, but very quickly either the belt or the wheels will collapse under the strain of trying to achieve the impossible.
Please explain 'impossible' please also explain why it will be an infinite speedthe aircraft has a take off speed, if that was 70mph then if your argument is correct (which it isn't) then the max speed would be 140 mph if it was a 747 with a take off speed much higher (guessing here) 150mph / 175 mph? then why is it infinite :shrug:
The bit that seems to be getting ignored is that the plane is moving forwards on the belt. The belt can move at the same speed as the wheels as long as the plane is stationary
What!
and the friction between the belt and wheels drags the wheels along at the same pace as it is moving. As soon as there is an outside force applied, such as the thrust from the plane's engines, which correlates with the wheels attached to it, the wheels will spin faster than the belt. They just will. It's impossible to deny that, but somehow you're managing to do so.
You fail to explain this 'outside force' To say 'They just will' is neither logical or scientific ... please explain
Is the belt moving in the same direction as the wheels, or in the reverse direction? A couple of your posts have suggested that the belt may be moving in the same direction,but I think it might be the way you've worded it.
Your second blue bit says that the wheels are moving at the same speed as the belt. This is in the opposite direction, yes? So the belt and wheels are moving at the same speed, but in the opposite direction? So when the plane moves forwards it increases the speed of the wheels. It's dead simple now. If the speed of the belt now increases, then so do the wheels of the plane as it's engines thrust it forwards. Then the belt increases its speed
The belt is the same speed as the wheels :shrug: ... should be a fairly simple concept to understand
I'm not sure whether the rules have changed or not. I just think a few of your posts are badly worded.
Please do share ... what bits are badly worded? I will be happy to clarify
It doesn't matter whether anyone reads those links or not. Most of it doesn't relate to this discussion. The only problem is that either; you don't understand the facts, you have worded the question wrongly from the start, or you are deliberately denying the facts to annoy me and everyone that agrees with me.
I am not trying to annoy you or anyone
although you do sound a little bit frustrated as you can't understand that you are wrong with most of your reasoning :shrug: ... TBH I suspect that google is your friend and has become your worst nightmare
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Try sticking your legs in the air then pushing your car, if you have no basic concept of physics why argue :shrug: ... read the references I posted i.e. frames of references (either will do) If you can't be bothered
think of it this way what has the greater resistance air or an aircraft? Newtons third law ... Can we please keep this scientific and factual
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Science is not made by consensus ... Just because lots of people are wrong or lots of people are right! does not change anything Facts are facts
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Google isn't needed for this discussion. It's all perfectly obvious what's correct and what isn't.
The "simple concept" isn't that simple, as much as you believe it is. In essence it's simple, but as soon as you bring the rest of the disccussion into play, it just doesn't work like that. It (impossibly) breaks the laws of physics.
To answer your first blue thing; it is impossible for the conveyor to match the speed of the plane's wheels, as long as the plane is in motion. Your question is completely irrelevant to the paragraph you've paired it with.
Second blue bit; I'm not sure why I thought you'd understand it. Two cars travel in opposite directions. What if one car travels 20 miles, but a conveyor belt travels 20 miles in the opposite direction? Both cars stay next to each other. What if the first car drives 40 miles whilst the conveyor belt moves 20 miles in the opposite direction? The car ends up 20 miles away, but the wheels have driven 40 miles.
Bit three; the wheel speed is infinite because the fictional belt is trying to keep up with the wheels. The plane moves forward no matter what, and the wheels face a great deal of friction against the conveyor. The conveyor tries to keep up with the speed of the wheels, but the planes engines keep propelling it forward, which makes the wheels spin faster, which makes the belt spin faster. Which makes the wheels spin faster. Which makes the belt spin faster. Which....
Third blue bit; I imagine should have a question mark after it (first badly worded bit. There are lots of questions without their respective marks). Not much to say about that. It just needs reading again. It makes perfect sense. I've read and re-read it a few times, and there's nothing I can do to make it simpler.
The outside force could be anything. A person pushing, a car towing, wind blowing, a giant football hitting it. It's very, very logical, if not scientific. It doesn't need to be scientific. It's all very, very clear that I'm right.
The next blue bit; yes, you claim the belt is moving at the same speed as the wheels, but the direction of movement in the first post seems different to later post, but only because of the way you've worded it. Like missing question marks and such.
So the belt is the same speed as the wheels? It isn't. It can try to be, or theoretically it will be, but the wheels will disintegrate immediately, or the belt will. Either way, I wouldn't want to be around when your paradox takes place. It would be messy.
The "simple concept" isn't that simple, as much as you believe it is. In essence it's simple, but as soon as you bring the rest of the disccussion into play, it just doesn't work like that. It (impossibly) breaks the laws of physics.
To answer your first blue thing; it is impossible for the conveyor to match the speed of the plane's wheels, as long as the plane is in motion. Your question is completely irrelevant to the paragraph you've paired it with.
Second blue bit; I'm not sure why I thought you'd understand it. Two cars travel in opposite directions. What if one car travels 20 miles, but a conveyor belt travels 20 miles in the opposite direction? Both cars stay next to each other. What if the first car drives 40 miles whilst the conveyor belt moves 20 miles in the opposite direction? The car ends up 20 miles away, but the wheels have driven 40 miles.
Bit three; the wheel speed is infinite because the fictional belt is trying to keep up with the wheels. The plane moves forward no matter what, and the wheels face a great deal of friction against the conveyor. The conveyor tries to keep up with the speed of the wheels, but the planes engines keep propelling it forward, which makes the wheels spin faster, which makes the belt spin faster. Which makes the wheels spin faster. Which makes the belt spin faster. Which....
Third blue bit; I imagine should have a question mark after it (first badly worded bit. There are lots of questions without their respective marks). Not much to say about that. It just needs reading again. It makes perfect sense. I've read and re-read it a few times, and there's nothing I can do to make it simpler.
The outside force could be anything. A person pushing, a car towing, wind blowing, a giant football hitting it. It's very, very logical, if not scientific. It doesn't need to be scientific. It's all very, very clear that I'm right.
The next blue bit; yes, you claim the belt is moving at the same speed as the wheels, but the direction of movement in the first post seems different to later post, but only because of the way you've worded it. Like missing question marks and such.
So the belt is the same speed as the wheels? It isn't. It can try to be, or theoretically it will be, but the wheels will disintegrate immediately, or the belt will. Either way, I wouldn't want to be around when your paradox takes place. It would be messy.
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Try sticking your legs in the air then pushing your car, if you have no basic concept of physics why argue :shrug: ... read the references I posted i.e. frames of references (either will do) If you can't be bothered
Eh?? How about I attach a couple of jet engines to my legs before I stick them in the air? The car will still move forwards. There is resistance in both cases. Resistance in the air or resistance on the ground. It's irrelevant. The resistance is there, be it ground friction or air friction.
Really, having a concept of physics has long gone out of the window, as I'm arguing against things you're making up as you go along. There's no need for any knowledge of physics anymore.
Science and fact has escaped you several pages ago.
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As mentioned the wheels are only there to support the plane and give comfy landings along with suspension. The bearings on the wheels act two ways therefore there will be no negative force being applied as the plane is powered. If the wheel bearings only rotated forward you would then get friction as they and the belt were pushing against each other.
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Use the jet engines
at least then you would be closer to working this out So your saying that pushing at air is the same as pushing at the ground :shake: As mentioned the wheels are only there to support the plane and give comfy landings along with suspension. The bearings on the wheels act two ways therefore there will be no negative force being applied as the plane is powered. If the wheel bearings only rotated forward you would then get friction as they and the belt were pushing against each other.
But the degree of friction is completely different! .. The wheels are not pushing against anything, they are rolling, that's what wheels do!
(Equal and opposite reaction)
I did say in the op that this could be a fun discussion, looks like I was right
Anyway I will be away for a few days and look forward to continuing this on my return .. bye for now
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Yes. Yes it is. But if you're going to continually deny that fact then this argument will never be over, unfortunately. A physicist on another forum that I've posted this thread on has confirmed that I'm correct. Enjoy your weekend.
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The way I understand this, it doesn't matter what the wheels or the conveyor belt do.
The plane will move forward, reach a takeoff speed of around 200mph(average guessish) and take off.
I hope the conveyor belt is long enough.
The plane will move forward, reach a takeoff speed of around 200mph(average guessish) and take off.
I hope the conveyor belt is long enough.
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This old chestnut ...
A propeller driven aircraft pulls itself through the air and a jet powered craft pushes itself through the air. Prior to take off, as long as contact with the ground remains reasonably frictionless - in our example, that the wheel bearings can withstand any speed thrown at them by the conveyor - the plane will take off.
HTH ...
A propeller driven aircraft pulls itself through the air and a jet powered craft pushes itself through the air. Prior to take off, as long as contact with the ground remains reasonably frictionless - in our example, that the wheel bearings can withstand any speed thrown at them by the conveyor - the plane will take off.
HTH ...
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Of course it does. It's because Splog won't accept the facts, so we have to keep repeating them until it sinks in.
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Splog, what are your physics qualifications?
whitewash
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can someone link me to a proper and by that i mean technical detailed answer to this i.e not one that just says 'it will fly' because in my head im missing something
due to the conveyor belt arrangement (unless ive misunderstood this part of the problem) means that the plane can only take off, it cannot for example move forwards or backwards, any attempt to move forwards will be met by an equal force in the opposite direction to resist the movement, the wheels (on account of not being driven, can spin as fast as they like in whatever direction they like, the important part of this that the plane it is attached to cannot move forwards or backwards without the conveyor belt resisting that movement via the wheels (therefore in my eyes it has infinite resistant via the undercarrage)
therefore the only way the plane (in my eyes) can take off is if the engines themselves can generate the lift required to take off from a standstill (harrier jump jet, missile, rocket etc) regardless of normal, lift induced takeoff via the wings. or the engines can provide enough lift to takeoff in the way that an ekranoplan directs the air under the wings to lift itself clear during takeoff, break the resistance provided by the rollers and then maintain normal flight thereafter
am i missing something fundemental of course.....
this is of course all pointless anyway, the cabin crew will be on strike anyway
due to the conveyor belt arrangement (unless ive misunderstood this part of the problem) means that the plane can only take off, it cannot for example move forwards or backwards, any attempt to move forwards will be met by an equal force in the opposite direction to resist the movement, the wheels (on account of not being driven, can spin as fast as they like in whatever direction they like, the important part of this that the plane it is attached to cannot move forwards or backwards without the conveyor belt resisting that movement via the wheels (therefore in my eyes it has infinite resistant via the undercarrage)
therefore the only way the plane (in my eyes) can take off is if the engines themselves can generate the lift required to take off from a standstill (harrier jump jet, missile, rocket etc) regardless of normal, lift induced takeoff via the wings. or the engines can provide enough lift to takeoff in the way that an ekranoplan directs the air under the wings to lift itself clear during takeoff, break the resistance provided by the rollers and then maintain normal flight thereafter
am i missing something fundemental of course.....
this is of course all pointless anyway, the cabin crew will be on strike anyway
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The plane moves exactly like it does on a tarmac runway.
It reaches take-off speed, and takes off.
The wheels may be turning at a much faster rate than normal, but the plane does as it normally does.
It reaches take-off speed, and takes off.
The wheels may be turning at a much faster rate than normal, but the plane does as it normally does.
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whitewash
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but surely for the plane to move along the conveyor when wheels must move faster than the conveyor which is a situation the original post says cannot happen as the conveyor belt control system will always match the speed of the wheels and therefore prevent the plane from moving along a horizontal plane?
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The conveyor belt can go as fast as it likes. It does not matter.
In reality, as has been said, there is minimal resistance in wheel bearings, friction etc. but this only results in the plane taking maybe one or two seconds longer to reach take off speed.
The plane will still move forward as normal.
In reality, as has been said, there is minimal resistance in wheel bearings, friction etc. but this only results in the plane taking maybe one or two seconds longer to reach take off speed.
The plane will still move forward as normal.
photon
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The damned problem has been incorrectly posed, no doubt due to t'internet and the passage of time. Unless the main aim was to encourage hearty debate...
http://www.boingboing.net/2006/12/11/airplanetreadmill-pr.html
http://www.boingboing.net/2006/12/11/airplanetreadmill-pr.html
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The answer has to be a resounding 'NO' because ....
As the thrust of the engines moves the plane forward, to say 5mph, the conveyor belt will try and match the speed (ie 5 mph in the opposite direction). This means the wheels would see a speed of 10mph - but wait a minute, the conveyor belt will try and match this speed so it increases to 10mph. But now the wheels would see 15mph so the conveyor belt increases it's speed again, and again, and again, until the damn thing is going so fast it flies apart destroying the plane and killing everyone on board long before it gets airborne!
RIP
Andy
As the thrust of the engines moves the plane forward, to say 5mph, the conveyor belt will try and match the speed (ie 5 mph in the opposite direction). This means the wheels would see a speed of 10mph - but wait a minute, the conveyor belt will try and match this speed so it increases to 10mph. But now the wheels would see 15mph so the conveyor belt increases it's speed again, and again, and again, until the damn thing is going so fast it flies apart destroying the plane and killing everyone on board long before it gets airborne!
RIP
Andy
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I like this explanation better ... <http://www.boingboing.net/2006/12/11/airplanetreadmill-pr.html>
"Or, we could interpret it as the author would mislead us into thinking, that the conveyor should move opposite the plane's attempted motion at a rate sufficient to keep it in place. Since the conveyor cannot prevent that motion, in theory its backward speed will quickly go to infinity. At which point the plane may fly through a wormhole to its destination, saving much time and fuel. Or a black hole will form that ingests plane, conveyor, and eventually Earth."
So, don't try this at home!!
"Or, we could interpret it as the author would mislead us into thinking, that the conveyor should move opposite the plane's attempted motion at a rate sufficient to keep it in place. Since the conveyor cannot prevent that motion, in theory its backward speed will quickly go to infinity. At which point the plane may fly through a wormhole to its destination, saving much time and fuel. Or a black hole will form that ingests plane, conveyor, and eventually Earth."
So, don't try this at home!!
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Damn I must be bored. Any who.
If we assume that the wheels rotational speed is taken at the axle and that the frame of reference for the plane and conveyor is the earth/ground:
Normally two forces will be acting on the wheel to make it spin, that of the plane (thrust) through the axle and that of gravity (pushing directly up against it). Remove one of these and the wheel does not spin.
In this situation though there are three. thrust, gravity and the movement of the conveyor. Thrust and the force from the conveyor are opposite to each other and both perpendicular to gravity.
Wheel rotational speed = x * y
On a conveyor then:
Wheel rotational speed = x + c * y
x = plane take off speed
y = a constant that is a function of wheel diameter
c = conveyor speed
Think that's it. If someone thinks they can formalise the rotational speed of the wheels more accurately then please do so.
If this still isn't enough you might tempt me to do a forces diagramme
If we assume that the wheels rotational speed is taken at the axle and that the frame of reference for the plane and conveyor is the earth/ground:
Normally two forces will be acting on the wheel to make it spin, that of the plane (thrust) through the axle and that of gravity (pushing directly up against it). Remove one of these and the wheel does not spin.
In this situation though there are three. thrust, gravity and the movement of the conveyor. Thrust and the force from the conveyor are opposite to each other and both perpendicular to gravity.
Wheel rotational speed = x * y
On a conveyor then:
Wheel rotational speed = x + c * y
x = plane take off speed
y = a constant that is a function of wheel diameter
c = conveyor speed
Think that's it. If someone thinks they can formalise the rotational speed of the wheels more accurately then please do so.
If this still isn't enough you might tempt me to do a forces diagramme
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I can't believe this is still going! lol
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Which part of " Yes it will take off, dont people understand? " :shrug:
http://www.youtube.com/watch?v=IZGdUAiMcPs
http://www.youtube.com/watch?v=IZGdUAiMcPs
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