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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 16:55 
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MaliA wrote:
Spinglo Sponglo! wrote:
As far as I can see the following is correct:

1) The Engines provide a force to move the plane in this ---> direction


HAND ON ROLLER SKATE PUSHING SKATE AGAINST TREADMILL


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 16:57 
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When you're pushing* the rollerskate, is the rotation speed of the wheels affected and different to when the rollerskate is statically-placed on the treadmill?

I'm rubbish at physics.

*acting as acceleration, either forwards or backwards, against the treadmill.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 16:58 
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Lave wrote:
I'm using slip to me that the rather than the wheel rolling across a surface, indeed it loses traction and it slides across a surface instead. In the way that a plane with it's brakes on would still take off, as eventually the force would overcome the coefficient of static friction between the tarmac and the rubber tread, and it would slide forward.

I'm saying that when interpreting this question people persume, that this slide can't occur, and as such the resistance between the wheel and the belt is sufficient to hold back the force of the jet. Which of course it can;t.


Why is anyone assuming that? The brakes are not applied, the wheels will turn freely.

They will turn at double their normal speed in this theoretical situation, and the plane will more forward at more-or-less its normal speed.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 16:58 
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Spinglo Sponglo! wrote:
I assume what is meant by the speed of the conveyor belt is the same as the speed of the wheel, that if you were standing still next to this conveyour belt then the plane would be stationary relative to you.

Malc


No, as that question is the same as, "Will a stationary plane take off?", which it obviously won't.

The debate really centres along whether the plane CAN move against such a treadmill. It can.

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:03 
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Curiosity wrote:
"Will a stationary plane take off?", which it obviously won't.

Actually, technically planes can take off from a stationary position (and don't mention Harriers), because the lift is provided purely by the wings dependent on the relative airflow. There's plenty of videos on youtube of paragliders taking off from a standing start, from the tops of hills where there's a high windspeed, for example.

That doesn't alter your point though, because this plane is not in a wind tunnel or anything, and it's not stationary.

Quote:
The debate really centres along whether the plane CAN move against such a treadmill. It can.


Agree.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:03 
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We've already posited a magical conveyor belt with a control system with zero lag. Who is to say what other arcane powers are held within its dark mechanical soul? I think it's perfectly reasonable that something of such fearsome power could stop a plane taking off, and I for one pray that is all the devastation it chooses to wreak.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:04 
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Tippy wrote:
We've already posited a magical conveyor belt with a control system with zero lag. Who is to say what other arcane powers are held within its dark mechanical soul? I think it's perfectly reasonable that something of such fearsome power could stop a plane taking off, and I for one pray that is all the devastation it chooses to wreak.


Welcome Tippy! Good answer.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:04 
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kalmar wrote:
Lave wrote:
I'm using slip to me that the rather than the wheel rolling across a surface, indeed it loses traction and it slides across a surface instead. In the way that a plane with it's brakes on would still take off, as eventually the force would overcome the coefficient of static friction between the tarmac and the rubber tread, and it would slide forward.

I'm saying that when interpreting this question people persume, that this slide can't occur, and as such the resistance between the wheel and the belt is sufficient to hold back the force of the jet. Which of course it can;t.


Why is anyone assuming that? The brakes are not applied, the wheels will turn freely.

They will turn at double their normal speed in this theoretical situation, and the plane will more forward at more-or-less its normal speed.


I was making an example of a different situation.

Question: Once the wheel of circumference 1m has rotated 360 degrees what length of belt has it rolled along?

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:04 
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Tippy wrote:
We've already posited a magical conveyor belt with a control system with zero lag. Who is to say what other arcane powers are held within its dark mechanical soul? I think it's perfectly reasonable that something of such fearsome power could stop a plane taking off, and I for one pray that is all the devastation it chooses to wreak.


Now THAT is a first post.

:)

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:06 
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Indeed it is!

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:09 
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Ok, so what's being said is that once you overcome the friction between the wheels and the treadmill the plane does travel along the treadmill?

Ok thena question, as I'm stuggling to visualise the wheel at the moment

On the runway the wheel is spinning around, on the treadmill is it spinning around twice as fast as it usually would, or is it not spinning at all?

As far as I can imagine it at the moment the engine is pushing the wheel to the right at the top,(clockwise) and the conveyor belt is pushing it to the left at the bottom (also clockwise), so the wheel is going twice as fast as it normally would in "real life". Now as I understand it, the coeffecient of friction increases exponentially (squared isn't it?) with speed. If this conveyor belt really can match whatever speed the wheel is travelling at, then this friction force is easilly going to match the thrust from the jet. The Plane goes no where.

As far as I can tell.

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:10 
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Lave wrote:
kalmar wrote:
Lave wrote:
I'm using slip to me that the rather than the wheel rolling across a surface, indeed it loses traction and it slides across a surface instead. In the way that a plane with it's brakes on would still take off, as eventually the force would overcome the coefficient of static friction between the tarmac and the rubber tread, and it would slide forward.

I'm saying that when interpreting this question people persume, that this slide can't occur, and as such the resistance between the wheel and the belt is sufficient to hold back the force of the jet. Which of course it can;t.


Why is anyone assuming that? The brakes are not applied, the wheels will turn freely.

They will turn at double their normal speed in this theoretical situation, and the plane will more forward at more-or-less its normal speed.


I was making an example of a different situation.


OK, but you accept that the plane will move forward and take off essentially as normal then, right?

Quote:
Question: Once the wheel of circumference 1m has rotated 360 degrees what length of belt has it rolled along?

[/quote]

2 x pi x D.

Sorry, 2m.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:17 
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kalmar wrote:
Lave wrote:
kalmar wrote:
Lave wrote:
I'm using slip to me that the rather than the wheel rolling across a surface, indeed it loses traction and it slides across a surface instead. In the way that a plane with it's brakes on would still take off, as eventually the force would overcome the coefficient of static friction between the tarmac and the rubber tread, and it would slide forward.

I'm saying that when interpreting this question people persume, that this slide can't occur, and as such the resistance between the wheel and the belt is sufficient to hold back the force of the jet. Which of course it can;t.


Why is anyone assuming that? The brakes are not applied, the wheels will turn freely.

They will turn at double their normal speed in this theoretical situation, and the plane will more forward at more-or-less its normal speed.


I was making an example of a different situation.


OK, but you accept that the plane will move forward and take off essentially as normal then, right?


Of course, the plane will take off regardless of what is happening between the wheels and the belt. The only thing I'm not decided on is how the wheels behave.

Quote:
Quote:
Question: Once the wheel of circumference 1m has rotated 360 degrees what length of belt has it rolled along?



2 x pi x D.

Sorry, 2m.


So you think for one rotation of the wheel of circumference 1m it travels along 2m of the belt?

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:18 
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Spinglo Sponglo! wrote:
Ok, so what's being said is that once you overcome the friction between the wheels and the treadmill the plane does travel along the treadmill?

There's not really any friction overcoming to be done. The wheel will *roll* on the treadmill belt, just as it would roll on a runway.

Quote:
Ok thena question, as I'm stuggling to visualise the wheel at the moment

On the runway the wheel is spinning around, on the treadmill is it spinning around twice as fast as it usually would, or is it not spinning at all?

Twice as fast.

Quote:
As far as I can imagine it at the moment the engine is pushing the wheel to the right at the top,(clockwise) and the conveyor belt is pushing it to the left at the bottom (also clockwise), so the wheel is going twice as fast as it normally would in "real life".

Correct.

Quote:
Now as I understand it, the coeffecient of friction increases exponentially (squared isn't it?) with speed.


This is not applicable. The coefficient involved here is the rolling resistance of the tyre, which is practically a fixed value until high speeds are reached, and then it increases linearly.
Remember, the speed of the wheel in a normal landing is higher than at takeoff, so theoretically doubling the speed isn't earth shattering.

Quote:
If this conveyor belt really can match whatever speed the wheel is travelling at, then this friction force is easilly going to match the thrust from the jet.

Picking some numbers, if the plane takes off at 120mph, the experienced speed of the wheel will be 240mph in the silly-treadmill-argument. Even if the force due to the rolling resistance is quadrupled in this case, it is still totally insignificant compared to the force of the engines.

Quote:
The Plane goes no where.


Noooo (cries)..


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:20 
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Lave wrote:
Quote:
Question: Once the wheel of circumference 1m has rotated 360 degrees what length of belt has it rolled along?


Quote:
2 x pi x D.

Sorry, 2m.


Eh? I said circumference. so you think for one rotation of the wheel of circumference 1m it travels along 2m of the belt?


If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:24 
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conveyor belt and Jumbo could in theory be in a massivly larger jumbo jet hence they can both fly. Weeee :?


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:28 
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kalmar wrote:
Spinglo Sponglo! wrote:
Ok, so what's being said is that once you overcome the friction between the wheels and the treadmill the plane does travel along the treadmill?

There's not really any friction overcoming to be done. The wheel will *roll* on the treadmill belt, just as it would roll on a runway.

Quote:
Ok thena question, as I'm stuggling to visualise the wheel at the moment

On the runway the wheel is spinning around, on the treadmill is it spinning around twice as fast as it usually would, or is it not spinning at all?

Twice as fast.

Quote:
As far as I can imagine it at the moment the engine is pushing the wheel to the right at the top,(clockwise) and the conveyor belt is pushing it to the left at the bottom (also clockwise), so the wheel is going twice as fast as it normally would in "real life".

Correct.

Quote:
Now as I understand it, the coeffecient of friction increases exponentially (squared isn't it?) with speed.


This is not applicable. The coefficient involved here is the rolling resistance of the tyre, which is practically a fixed value until high speeds are reached, and then it increases linearly.
Remember, the speed of the wheel in a normal landing is higher than at takeoff, so theoretically doubling the speed isn't earth shattering.

Quote:
If this conveyor belt really can match whatever speed the wheel is travelling at, then this friction force is easilly going to match the thrust from the jet.

Picking some numbers, if the plane takes off at 120mph, the experienced speed of the wheel will be 240mph in the silly-treadmill-argument. Even if the force due to the rolling resistance is quadrupled in this case, it is still totally insignificant compared to the force of the engines.

Quote:
The Plane goes no where.


Noooo (cries)..


Where is the force coming from? If the speeds are the same there is no acceleration, if there is no acceleration there is no force (F=ma and all that) If you can explain where the force is coming from, then I will happily concede defeat.

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:32 
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kalmar wrote:
Lave wrote:
Quote:
Question: Once the wheel of circumference 1m has rotated 360 degrees what length of belt has it rolled along?


Quote:
2 x pi x D.

Sorry, 2m.


Eh? I said circumference. so you think for one rotation of the wheel of circumference 1m it travels along 2m of the belt?


If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


Hmm, ok, I think I'm working out the difference between us. I proposing that a wheel of 1m circumference rotated once, then it would cover 1m of the surface it was rolling across if it did not slip across that surface. (perfect traction or whatever). In that situation the wheel and belt could reach a balance due to the plane taking off above them. And so the situation is unphysical and they would melt/not exist.

Whether that represents the question, is another matter! :)

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:33 
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Malc: The force propelling it forward is the engine. The only opposing force (over the normal case) is the very minor one I've mentioned, the increase in rolling resistance and bearing drag. It has to accelerate.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:34 
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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:39 
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Lave wrote:
Quote:
If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


Hmm, ok, I think I'm working out the difference between us. I proposing that a wheel of 1m circumference rotated once, then it would cover 1m of the surface it was rolling across if it did not slip across that surface. (perfect traction or whatever). In that situation the wheel and belt could reach a balance due to the plane taking off above them. And so the situation is unphysical and they would melt/not exist.


Can you stop proposing that then please, because it is even more nonsensical than the original question, has nothing to do with that, and is going to confuse people :)

In fact, would you mind getting a rollerskate or something, put some paint on one of the wheels and roll it forwards one meter on sheet of a newspaper, whilst pulling the newspaper backwards by one meter? Nothing will explode or melt, except for me if you keep on about this :)


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:40 
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kalmar wrote:
Malc: The force propelling it forward is the engine. The only opposing force (over the normal case) is the very minor one I've mentioned, the increase in rolling resistance and bearing drag. It has to accelerate.


so you're saying that as the plane goes faster, the wheels do not (which is also what I think Lave is alluding to as well)? If that's the case then fine, the plane takes off. But is it the case? Why would the plane be travelling faster than the wheels? I presume they must be designed to hadle at least twice the normal speed of use...

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:43 
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Spinglo Sponglo! wrote:
kalmar wrote:
Malc: The force propelling it forward is the engine. The only opposing force (over the normal case) is the very minor one I've mentioned, the increase in rolling resistance and bearing drag. It has to accelerate.


so you're saying that as the plane goes faster, the wheels do not (which is also what I think Lave is alluding to as well)?

Definitely, definitely, definitely not :)

Quote:
If that's the case then fine, the plane takes off. But is it the case? Why would the plane be travelling faster than the wheels?


It wouldn't. The wheels move at the same speed as the plane, they are kind of attached to it. However, they will rotate at twice the normal velocity for any given forward speed of the plane, if the "runway" is also moving backwards as described.

That's all there is to it.

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:47 
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kalmar wrote:
Lave wrote:
Quote:
If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


Hmm, ok, I think I'm working out the difference between us. I proposing that a wheel of 1m circumference rotated once, then it would cover 1m of the surface it was rolling across if it did not slip across that surface. (perfect traction or whatever). In that situation the wheel and belt could reach a balance due to the plane taking off above them. And so the situation is unphysical and they would melt/not exist.


Can you stop proposing that then please, because it is even more nonsensical than the original question, has nothing to do with that, and is going to confuse people :)

In fact, would you mind getting a rollerskate or something, put some paint on one of the wheels and roll it forwards one meter on sheet of a newspaper, whilst pulling the newspaper backwards by one meter? Nothing will explode or melt, except for me if you keep on about this :)


Ah yes, but will the the ink particles be half as densely populated? Ey?

I'm just bringing it up because thats a typical assumption in Physics for the vast amount of theory questions we do. I suspect your from a different background and treating the wheel differently, I think thats interesting so I bugged you about it.

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:49 
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Lave wrote:
kalmar wrote:
Lave wrote:
Quote:
If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


Hmm, ok, I think I'm working out the difference between us. I proposing that a wheel of 1m circumference rotated once, then it would cover 1m of the surface it was rolling across if it did not slip across that surface. (perfect traction or whatever). In that situation the wheel and belt could reach a balance due to the plane taking off above them. And so the situation is unphysical and they would melt/not exist.


Can you stop proposing that then please, because it is even more nonsensical than the original question, has nothing to do with that, and is going to confuse people :)

In fact, would you mind getting a rollerskate or something, put some paint on one of the wheels and roll it forwards one meter on sheet of a newspaper, whilst pulling the newspaper backwards by one meter? Nothing will explode or melt, except for me if you keep on about this :)


Ah yes, but will the the ink particles be half as densely populated? Ey?

I'm just bringing it up because thats a typical assumption in Physics for the vast amount of theory questions we do. I suspect your from a different background and treating the wheel differently, I think thats interesting so I bugged you about it.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:50 
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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:52 
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kalmar wrote:
Spinglo Sponglo! wrote:
kalmar wrote:
Malc: The force propelling it forward is the engine. The only opposing force (over the normal case) is the very minor one I've mentioned, the increase in rolling resistance and bearing drag. It has to accelerate.


so you're saying that as the plane goes faster, the wheels do not (which is also what I think Lave is alluding to as well)?

Definitely, definitely, definitely not :)

Quote:
If that's the case then fine, the plane takes off. But is it the case? Why would the plane be travelling faster than the wheels?


It wouldn't. The wheels move at the same speed as the plane, they are kind of attached to it. However, they will rotate at twice the normal velocity for any given forward speed of the plane, if the "runway" is also moving backwards as described.

That's all there is to it.

(is this a wind-up or something? SUSPICIOUS FACE)


No wind up.

So let me get this straight:

The plane and the wheels are travelling at the same speed from left to right?
The treadmill is travelling at the same speed but from right to left?

If that is the case, then I repeat my assertation, where is the net accelleration? where is the net force?

If that isn't the case what am I missing?

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:53 
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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:58 
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kalmar wrote:
Lave wrote:
Quote:
If the wheel travels forwards 1m in 1 second, and the belt travels backwards 1m during this time, then the length of belt touched by the wheel is 2m.


Hmm, ok, I think I'm working out the difference between us. I proposing that a wheel of 1m circumference rotated once, then it would cover 1m of the surface it was rolling across if it did not slip across that surface. (perfect traction or whatever). In that situation the wheel and belt could reach a balance due to the plane taking off above them. And so the situation is unphysical and they would melt/not exist.


Can you stop proposing that then please, because it is even more nonsensical than the original question, has nothing to do with that, and is going to confuse people :)


You reckon this is all that is gonna confuse people within this thread :shock:

Have a fun weekend arguing guys, I'll laugh at this on Monday morning at work!

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 17:59 
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Spinglo Sponglo! wrote:
kalmar wrote:
Spinglo Sponglo! wrote:
kalmar wrote:
Malc: The force propelling it forward is the engine. The only opposing force (over the normal case) is the very minor one I've mentioned, the increase in rolling resistance and bearing drag. It has to accelerate.


so you're saying that as the plane goes faster, the wheels do not (which is also what I think Lave is alluding to as well)?

Definitely, definitely, definitely not :)

Quote:
If that's the case then fine, the plane takes off. But is it the case? Why would the plane be travelling faster than the wheels?


It wouldn't. The wheels move at the same speed as the plane, they are kind of attached to it. However, they will rotate at twice the normal velocity for any given forward speed of the plane, if the "runway" is also moving backwards as described.

That's all there is to it.

(is this a wind-up or something? SUSPICIOUS FACE)


No wind up.

So let me get this straight:

The plane and the wheels are travelling at the same speed from left to right?
The treadmill is travelling at the same speed but from right to left?


The surface of the treadmill is travelling from right to left, but has no noticeable effect on the motion of the plane, which is still travelling from left to right at its normal speed.

If the plane moves forwards at 10mph, the treadmill moves backwards at 10mph. But the plane still moves forwards at 10mph.

Quote:
If that is the case, then I repeat my assertation, where is the net accelleration? where is the net force?

I repeat that the force propelling it from the left is the jet engine acting on the air behind it, as usual (simplified, but acceptable for this). And the treadmill acts on the plane only indirectly via the rolling resistance of the tyres and other minor effects.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 18:20 
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OK, I think I've got this now. Or rather I thought I did, No I do, I think what I need is some actual numbers. What Force can a Jumbo's engines provide? What Force is the resistance of a wheel on a treadmill?

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 18:33 
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I can't believe so many people get this wrong. This topic was banned over at the Mythbusters forums, because people kept arguing that a plane on a treadmill can't take off. Despite actual evidence that it can. Because they did it.

You might as well say 'can a plane fly along a treadmill running in the opposite direction?'. The only force the wheels exert on the plane is the friction of their bearings. It doesn't matter how fast you run that treadmill, as long as the wheels can take the stress.

If the treadmill was directly working against the planes body, in some way, then it wouldn't be able to take off, but the wheels are basically bearings, designed to allow the plane and surfaces it interacts with to move freely against each other. If they didn't do that, and there was enough friction generated by their turning to significantly act against the thousands of pounds of thrust jet engines produce, then you wouldn't be able to land any planes. That friction would cause them to be ripped off as soon as they touch the runway.

Here's another example. Take a rear-wheel drive car. Put the front wheels on a treadmill, and spin them up to 200mph, in reverse. Get in car, put it in reverse, then press on the accelerator. What happens? You'll probably wreck the front tyres as you reverse them off the treadmill, and they hit the stationary floor at 200mph. (the car won't go off at 200 mph, because the front wheels aren't being driven)


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 19:00 
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Spinglo Sponglo! wrote:
OK, I think I've got this now. Or rather I thought I did, No I do, I think what I need is some actual numbers. What Force can a Jumbo's engines provide? What Force is the resistance of a wheel on a treadmill?

Malc


Here's what I wrote for the other thread:
me wrote:
Let's see, a 747's engines can produce about 100,000 pound-foot of force. That's about 500,000N. (round numbers here).


You can work out for yourself the rolling resistance, but you'll have to find the coefficient for the tyres used first.
Hint: it's bugger-all, relatively speaking.


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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 19:35 
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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 19:47 
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myoptika wrote:
MrD wrote:
myoptika wrote:
What about if there was 1G of centrifugal force affecting the plane's wings in the bipolar direction? Then there'd be a case for it not being able to take off.

It would topple to the side.


DON'T BE AN IDIOT. There's no such thing as a centrifugal force.

WRONG!!!

http://en.wikipedia.org/wiki/Centrifuga ... onceptions

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 19:54 
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I no longer want to be king of the subeds, on the basis that you are a bunch of



COMPLETE DULLARDS.

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 20:07 
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Craster wrote:
I no longer want to be king of the subeds, on the basis that you are a bunch of



COMPLETE DULLARDS.


I'm desperately trying to find that quote that goes;
"Those who want power and the least desirable to use it" and also mentions the contra? Anyway, by following that premise I VOTE YOU, CRASTERZARD!

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 Post subject: Re: A classic Internet debate...
PostPosted: Fri Apr 04, 2008 22:29 
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Spinglo Sponglo! wrote:
OK, I think I've got this now. Or rather I thought I did, No I do, I think what I need is some actual numbers. What Force can a Jumbo's engines provide? What Force is the resistance of a wheel on a treadmill?

Malc


Okay, so we've moved from an infinite force to a measurable one. PROGRESS!

To get an idea of the numbers involved, think of a pull-back-and-then-go toy car compared to a jet engine. That's about the forces involved.

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 Post subject: Re: A classic Internet debate...
PostPosted: Sat Apr 05, 2008 10:04 
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 Post subject: Re: A classic Internet debate...
PostPosted: Sat Apr 05, 2008 11:21 
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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 11:10 
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My mate finally replied, and says:

Quote:
No it wouldn't. Two possible answers here one theoretical and one experimental.

Theoretical, what you said - no air flow.

Experimental, no one does it so therefore it doesn't work. Aircraft carriers would probably be a lot simpler if you could :)

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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 11:41 
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He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.

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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 12:07 
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ComicalGnomes wrote:
My mate finally replied, and says:

Quote:
No it wouldn't. Two possible answers here one theoretical and one experimental.

Theoretical, what you said - no air flow.


But there is airflow.

Quote:
Quote:
Experimental, no one does it so therefore it doesn't work.

But mythbusters tried it and it flew.

Bit of a waste of time that one, wunnit? ;)


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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 13:42 
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Craster wrote:
He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.


Still disagree with this :)

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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 14:03 
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ComicalGnomes wrote:
Craster wrote:
He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.


Still disagree with this :)


Arggghhhh!

http://www.youtube.com/watch?v=S377HwOthjo

http://www.youtube.com/watch?v=0ul_5DtMLhc


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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 14:06 
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ComicalGnomes wrote:
Craster wrote:
He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.


Still disagree with this :)


The wheels have no effect on the drive of the plane - the engines work directly on the body of the plane. It's not like a car, where the wheels are what causes the movement. For example, you can get water take off/landing planes that don't have any wheels, but two hulls. The wheels on a plane are there to reduce friction rather than increase it, to put it simply.

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 Post subject: Re: A classic Internet debate...
PostPosted: Sun Apr 06, 2008 22:27 
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baron of techno

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ComicalGnomes wrote:
Craster wrote:
He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.


Still disagree with this :)


Well, give a reason then. Otherwise you're ignoring basic physics and shit, and physics does not like to be ignored...


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 Post subject: Re: A classic Internet debate...
PostPosted: Mon Apr 07, 2008 9:38 
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ComicalGnomes wrote:
Craster wrote:
He's missed what most of us were saying though, which is that the plane would ignore the conveyer and move forwards anyway, thus creating air flow.


Still disagree with this :)


I think I've finally come round to the "yes it does" brigade.

Sorry CG

Malc

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 Post subject: Re: A classic Internet debate...
PostPosted: Mon Apr 07, 2008 10:19 
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Hurrah! Is that everybody, then?

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 Post subject: Re: A classic Internet debate...
PostPosted: Mon Apr 07, 2008 10:22 
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*Yawn*

What did I miss?

What's that you say? An argument? On the internet?

Shocking!

*Goes back to sleep*

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