*light blue touch paper*

[Steve]

This is as simple as its going to get. If the Prince still doesn't think it can take off, then he is clearly an idiot.

Doesn't mean he's an idiot, just means he thinks about it in a different way.

 

[Yuri]

Doesn't mean he's an idiot, just means he thinks about it in a different way.

Yeah, he thinks about it in a way that is incorrect. As in, not right in the slightest bit of at all.

And his stubborn nature about the whole ordeal is what makes him into an idiot.



This wouldn't be a riddle if it didn't trick people right off, and then make them realize why and how they were tricked. But some people are just too stubborn and full of themselves. Its really quite funny.

 

[PriNcE oF SpAcE]

The human pulls the rope to go forward. The wheels of the skates are spinning with the conveyor belt, but it doesn't matter because the rope is independent of the movement of the conveyor belt, so the person is free to advance along the conveyor belt by pulling the rope.

this is where you're wrong though. the question specifically states that the conveyer belt moves at the same speed of the the plane. what you're doing in your example is pulling yourself faster than the conveyer belt moves. not equal speed.

if what you're saying is true, if you were on the belt with your rollerblades and the the belt started to move, then you'd be standing still wheels spinning...this is not true however, you'd move with the belt. if the belt moved fast enough you might be ending up with wheels spinning and not moving(key being not moving)

 

[Yuri]

My god you are dense and arrogant!

 

[Steve]

this is where you're wrong though. the question specifically states that the conveyer belt moves at the same speed of the the plane. what you're doing in your example is pulling yourself faster than the conveyer belt moves. not equal speed.

Right, but just because they're moving at the same speed doesn't mean that it pulls on the plane. The force pushing the plane forward is unaffected by the force of the conveyor belt, because the wheels act like a lubricant.

Let me give you another example.

Replace the plane with a human again.

Replace the wheels with the human's bottom and the conveyor belt being coated in a sort of super-lubricant oil type substance.

Angle the conveyor belt downward slightly, and we'll replace the force of the jets with gravity.

Now, normally, if you sit down on the conveyor belt without the lubricant, the conveyor belt would just push you backwards, right? But you have the lubricant on your bottom and the conveyor is coated, so you just slide down the slope of the conveyor belt. The conveyor belt's speed will increase as you accelerate, but it doesn't matter because the lubricant negates the force the conveyor creates, and gravity does its job of moving you forward.

I'm sorry, I know it's really poorly worded.

 

[PriNcE oF SpAcE]

My god you are dense and arrogant!

if anyone's being arrogant then it's you.

nobody have proven that the aircraft will take off yet... the only scenarios so far where the plane manages to take off people haven't accounted for gravity or friction.


an example back to the rope and tree.

if you were to stand up close to the tree on the conveyer belt, the rope hanging loosely, what happens when the conveyer belt starts to move?

that's right you'd be pulled backwards and the rope would straighten out and tighten. if the rope wasn't effected by the movement of the conveyer belt, how come it now suddenly changes? this proves that the rope is infact effected by the movment thru the person. likewise the performance(the ability to push forward the plane) of the engines of an aircraft will be effected by the movement of the ground thru the plane.

 

[kirovman]

Someone needs a lesson in the basic principles of relativity.

Once you've done that, read this: the plane's wings need to be moving relative to the air in order to take off. Which it will not be if it is on this conveyor belt. Ground speed doesn't matter, airspeed does.

What's all this about rope? It's overcomplicating the simple issue.

 

[Maxi]

Someone needs a lesson in the basic principles of relativity.

Once you've done that, read this: the plane's wings need to be moving relative to the air in order to take off. Which they will not be if it is on this conveyor belt. Ground speed doesn't matter, airspeed does.

What's all this about rope? It's overcomplicating the simple issue.

Exactly.

 

[Yuri]

What's all this about rope? It's overcomplicating the simple issue.

I think it was made in response to an overcomplicating by Mr. Space, at an attempt to explain it to him.

Didn't seem to work.




Oh, and I would listen to kirov. He knows what he is talking about.



The internet: A place to pretend to know everything, when in actuality you don't.

 

[Steve]

Kirov's here. Whether I'm wrong or right, I'll go with him.

 

[PriNcE oF SpAcE]

Oh, and I would listen to kirov. He knows what he is talking about.

ok I will, but as far as I can tell he's agreeing with me.

the plane won't move when on the conveyer belt, and thus will not have enough air passing the wings for take off.

sorry kiro if I'm misinterpreting what you're saying.

 

[Yuri]

Actually I misinterpreted what kirov said, too.... heh.

Could you clarify? Why wouldn't the plane's wings be moving when on the conveyor belt?

 

[kirovman]

Yeah, once you get enough thrust, the friction should be overcome.

This part of what I wrote was incorrect: "Which they will not be if it is on this conveyor belt. " because I just realised some things when I was thinking.

But the rest was right. The plane will take a little longer to take off.

 

[Steve]

See, your friction is there, PoS, but it's mostly insignificant.

 

[kirovman]

Yeah, that's quite a good trick, that.

 

[Yuri]

See, your friction is there, PoS, but it's mostly insignificant.

Heh, you just called him a "POS." That wasn't very nice.

I would think that the friction would be too insignificant to even take into account...

 

[Steve]

Heh, you just called him a "POS." That wasn't very nice.

I would think that the friction would be too insignificant to even take into account...

Oh crap! I didn't even realize that. Sorry, Princey!

 

[PriNcE oF SpAcE]

Right, but just because they're moving at the same speed doesn't mean that it pulls on the plane. The force pushing the plane forward is unaffected by the force of the conveyor belt, because the wheels act like a lubricant.

Let me give you another example.

Replace the plane with a human again.

Replace the wheels with the human's bottom and the conveyor belt being coated in a sort of super-lubricant oil type substance.

Angle the conveyor belt downward slightly, and we'll replace the force of the jets with gravity.

Now, normally, if you sit down on the conveyor belt without the lubricant, the conveyor belt would just push you backwards, right? But you have the lubricant on your bottom and the conveyor is coated, so you just slide down the slope of the conveyor belt. The conveyor belt's speed will increase as you accelerate, but it doesn't matter because the lubricant negates the force the conveyor creates, and gravity does its job of moving you forward.

I'm sorry, I know it's really poorly worded.

I know where you're going with this, I was about to use a similar example. except I found out that using gravity to replace engine thrust is a bad idea.

reverse the gravity and you'll be moving upwards, which means that the force gravity applies would be similar to that of a rocket able to take off.

what you need to understand here is that the way I look at it for plane to be able to move opposite direction of a moving run way, the plane will have to have applied enough force to cancel out the friction between the run way and the wheels. essentially the run way moving in an opposite direction of the plane will function as if brakes was applied to the wheels. if the plane manages to cancel out this then the force applied is similar to that of a rocket. so if the plane is able to apply this force, holding the plane back and giving the plane full throttle, then releasing would make the plane take off from a standstill position(like a rocket)

if you have a plane without wings it won't take off from the run way unless you apply enough force for it to launch like a rocket. yes in the case of the conveyer belt the plane will move relatively to the moving part of the the belt, not the belt itself nor the air around it which is required for it to, cancel out the friction and gravity(lift off)

 

[Steve]

I just wanna make sure you understand this.

You know the wheels are attached to an axle, right? And that they turn? They turn. That turning cancels out all but an insignificant amount of your friction.

I'm done with this.

 

[Maxi]

I know where you're going with this, I was about to use a similar example. except I found out that using gravity to replace engine thrust is a bad idea.

reverse the gravity and you'll be moving upwards, which means that the force gravity applies would be similar to that of a rocket able to take off.

what you need to understand here is that the way I look at it for plane to be able to move opposite direction of a moving run way, the plane will have to have applied enough force to cancel out the friction between the run way and the wheels. essentially the run way moving in an opposite direction of the plane will function as if brakes was applied to the wheels. if the plane manages to cancel out this then the force applied is similar to that of a rocket. so if the plane is able to apply this force, holding the plane back and giving the plane full throttle, then releasing would make the plane take off from a standstill position(like a rocket)

if you have a plane without wings it won't take off from the run way unless you apply enough force for it to launch like a rocket. yes in the case of the conveyer belt the plane will move relatively to the moving part of the the belt, not the belt itself nor the air around it which is required for it to, cancel out the friction and gravity(lift off)

Lol


6char.

 

[Vegeta897]

How is it possible that this thread is continuing.

PoS, no offense, but are you blind? Not only has the great mind Kirov literally changed his opinion to agree with the rest of us right before your eyes, but there are still 50000 results in google saying you are wrong as well.

You keep bringing up this friction nonsense, but the wheels are there to COUNTER THE FRICTION. The only thing different to a plane taking off normally is 2x speed of wheels. I swear to God, you simply must understand this and stop ignoring the facts and bringing up friction again and start from square one again, not learning a thing.

Wheels cancel friction. They do it on a normal runway too. And sea planes cancel friction with their smooth ski's on the water.

And here's another thing:

The situation of the plane not taking off is a physical paradox. Why? Well, you say the plane won't move, and that means the belt isn't moving. Right? But you are saying the belt is counteracting the movement of the plane. But there is none according to you! So, paradox, you lose.

Go google it.

Please do attempt to point out a flaw in my post above. If you say "you aren't taking gravity into account" without any real explaination (like you have been attempting this whole time) I'm simply just... Giving up on you.

 

[Sulkdodds]

I love you Steve. If someone had explained it to me as making-sense-ingly as you did, I would have got it on like page 3 or something.

 

[Steve]

I love you, Sulk. You sig my weird, half-drunk dream hallucinations quotes.

 

[Sulkdodds]

You do have the best quotes.

Well, I hate to sound like some sort of asshole, but...

...just cracks me up for some reason.

 

[Ennui]

What the hell. Honestly, can it take off or not?

 

[PriNcE oF SpAcE]

How is it possible that this thread is continuing.

PoS, no offense, but are you blind? Not only has the great mind Kirov literally changed his opinion to agree with the rest of us right before your eyes, but there are still 50000 results in google saying you are wrong as well.

You keep bringing up this friction nonsense, but the wheels are there to COUNTER THE FRICTION. The only thing different to a plane taking off normally is 2x speed of wheels. I swear to God, you simply must understand this and stop ignoring the facts and bringing up friction again and start from square one again, not learning a thing.

Wheels cancel friction. They do it on a normal runway too. And sea planes cancel friction with their smooth ski's on the water.

And here's another thing:

The situation of the plane not taking off is a physical paradox. Why? Well, you say the plane won't move, and that means the belt isn't moving. Right? But you are saying the belt is counteracting the movement of the plane. But there is none according to you! So, paradox, you lose.

Go google it.

Please do attempt to point out a flaw in my post above. If you say "you aren't taking gravity into account" without any real explaination (like you have been attempting this whole time) I'm simply just... Giving up on you.

wheels reduce friction, they don't cancel it. it's still there.

indeed there might be a paradox, however I'm not the one loosing, you are. if the paradox is true then neither the belt nor the airplane will move, so the plane won't take off. both will just sit there still.

oh and by the way to go around the paradox the belt would mimic the speed at which the air is thrusted from the engines(since the air will be moving even if the plane is still) translated into the normal speed of the plane(if it was moving) this way even if the plane itself isn't moving the conveyer belt would.

 

[kirovman]

http://physicsforums.com/showthread.php?t=101259

Here's the Physicsforum's take on it:

I feel the need to add some more. Those who are saying that the plane would not take off are basing that on reading the problem as defining the plane to be stationary. Since the question is poorly worded and barring a clarification from the writer, it is possible to interpret the question that way. However, the problem with doing that is two-fold: First, if the problem simply reduces to: "If a plane is stationary, will it take off?", why even bother asking the question? It's so basic that it's pointless. Second, just defining that the plane is stationary does not address the question of whether such a thing is physically possible. And while we engineers are arguing about what is physically possible, those who are saying the plane is stationary are simply assuming it without basis in physical reality. I think if you analyze the problem - think through the steps of how it would work - you'd find that it would be useless to ask the question you are describing for the two reasons above.

However, if you guys do think that your position is physically possible, please follow the steps of how it would happen and explain it. If you do that, I think you will find the scenario falls apart. Let me start it:

Step 1: A plane is sitting stationary on a stationary treadmill.

Step 2: The plane fires up it's engine and begins to accelerate.

Step 3: The treadmill senses the motion/acceleration.
-------Step 3 is a toughie: how can the treadmill sense the acceleration? Unlike a car, which exerts a direct force on the treadmill in order to accelerate, the plane does not. About all you could do is sense the motion with sensors along the surface of the treadmill.

Step 4: The treadmill responds to the motion of the plane and begins to move.....how fast?
-----Step 4 is where the scenario completely falls apart. Since the treadmill is not capable of exerting a direct force on the plane in the way that it can on a car, it is not possible for the treadmill to instantly react to it's motion and keep it stationary like it can a car. It could keep a car stationary regardless of what the car does - accelerate, decelerate, whatever. With the plane, the only way the treadmill can react is by speeding up - and while the treadmill accelerates, the plane is still accelerating with respect to the ground. The treadmill can't stop the plane and keep it stationary in a stable situation like it can with the car.

The only physically possible way to stop the plane is to accelerate the wheels until the wheels actually fail - heat up, burn up, disintegrate, ripping the landing gear off the plane. If the problem was meant to allow that, fine - you could always make higher speed wheels and then the problem becomes a battle between the engineering of the wheels and the acceleration capability of the treadmill. But again, that's not a very useful discussion. Plus, the scenario is uncontrolled - the treadmill is not under any sort of active control - it's not reacting to anything the plane is doing, you just turn on the treadmill when the plane fires up it's engine and see who wins the battle.

 

[PriNcE oF SpAcE]

haha somebody really should contact myth busters... I want to see this as an actual experiement.

 

[Steve]

Definitely. I freakin' love mythbusters.

 

[Yuri]

wheels reduce friction, they don't cancel it. it's still there.

indeed there might be a paradox, however I'm not the one loosing, you are. if the paradox is true then neither the belt nor the airplane will move, so the plane won't take off. both will just sit there still.

oh and by the way to go around the paradox the belt would mimic the speed at which the air is thrusted from the engines(since the air will be moving even if the plane is still) translated into the normal speed of the plane(if it was moving) this way even if the plane itself isn't moving the conveyer belt would.

But the friction is negligible either way...

I'd read kirov's post quote. My assumption was that the wheels would not burn up and that the motion sensors were magical in some way.

 

[Vegeta897]

Ok well PoS you just ignored my post and started picking at an unimportant note... And now you are going with the fallback option of "We don't know unless we try"

Honestly it's such a simple process that it's like saying "Oh we don't know of a giant sheet of glass would break if we shot a missle with the word 'pork' written on it because it hasn't been tried in real life"

Kirov's quote explains the paradox I was referring to.

Plane taking off = works
Plane not taking off = paradox

Who wins?

 

[Ravioli]

It would not take off because the plane is not moving at all so no wind resistance on the wings will push it up.

 

[Steve]

Read the thread and see if you still think the same.

 

[Yuri]

It would not take off because the plane is not moving at all so no wind resistance on the wings will push it up.

lol

 

[Steve]

I used to be like him!

 

[PriNcE oF SpAcE]

Ok well PoS you just ignored my post and started picking at an unimportant note... And now you are going with the fallback option of "We don't know unless we try"

Honestly it's such a simple process that it's like saying "Oh we don't know of a giant sheet of glass would break if we shot a missle with the word 'pork' written on it because it hasn't been tried in real life"

Kirov's quote explains the paradox I was referring to.

Plane taking off = works
Plane not taking off = paradox

Who wins?

actually I didn't.

if it was so simple there wouldn't be so many people discussing it and still not agreeing.

plane taking off= works...you haven't proven this yet.

plane not taking off= paradox. the plane not taking off is in itself not a paradox. when you spoke of paradox before you were refering to the question, and I agreed that it might very well be paradoxal, but the outcome is the plane not taking off, which I've been saying the whole time, hence I win.

as for kirovmans quote, the quy is already working from the base that the experiement is impossible to do, which will result in the plane not taking off.

when he tries to go ahead with the experiement anyways he makes numerious mistakes that does not correspond with the requirements of the riddle(question whatever)

 

[Vegeta897]

when he tries to go ahead with the experiement anyways he makes numerious mistakes that does not correspond with the requirements of the riddle(question whatever)

Finish your post, please. What mistakes?

 

[Glirk Dient]

Ok...let me try to explain this again.

Planes engines fire up and pushes it forward 10mph. Belt begins to turn going opposite way of 10mph.

Planes wheels now move at 20,ph while plane moves at 10mph. The planes acceleration is based off the engine and pulls itself through the air, not the ground. So the wheels are spinning really fast and the friction is so small it is negligable. So there is no way for the belt to make a plane stationary. A planes driving force is its engines, no wheels. If this were a car the answer would be yes because a car moves with its wheels.

 

[Vegeta897]

Ok...let me try to explain this again.

Planes engines fire up and pushes it forward 10mph. Belt begins to turn going opposite way of 10mph.

Planes wheels now move at 20,ph while plane moves at 10mph. The planes acceleration is based off the engine and pulls itself through the air, not the ground. So the wheels are spinning really fast and the friction is so small it is negligable. So there is no way for the belt to make a plane stationary. A planes driving force is its engines, no wheels. If this were a car the answer would be yes because a car moves with its wheels.

Thanks Glirk.

That right there, Prince. Glirk's words. I want you to tell me what is wrong with that. If you aren't specific, and just say something like "durrr gravity durr friction!" then you admit defeat.

 

[Pi Mu Rho]

I'd like to know what Prince of Space thinks propels aeroplanes through the air.