You have a plane and a conveyor belt.

[spidey07]

Originally posted by: JujuFish

Originally posted by: spidey07
Exactly. You can't take off if you can't move.

From the OP, the plane moves.

Fixed.

Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

 

[JujuFish]

Originally posted by: spidey07
Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

I suggest you do the same. Yes, the scheme in the OP would work... if we were talking about a car. Cars move forward by pushing off of the ground. Planes do not.

 

[PurdueRy]

Originally posted by: spidey07

Originally posted by: JujuFish

Originally posted by: spidey07
Exactly. You can't take off if you can't move.

From the OP, the plane moves.

Fixed.

Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

I like how your the only one not getting it ....well maybe 2

 

[SampSon]

The people who are trying to say the plane would not take off are simply relying on the semantics of the OP's post.

Even if you take the wording of the post at face value, the reality that the plane will not take off is still unrefutable.

 

[spidey07]

Originally posted by: JujuFish

Originally posted by: spidey07
Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

I suggest you do the same. Yes, the scheme in the OP would work... if we were talking about a car. Cars move forward by pushing off of the ground. Planes do not.

Fine.

I'll make it very simple for you...

If the plane moves forward a single inch then the conditions of the OP are not true.

I still can't believe we have boneheads thinking that it can. Back to school for them.

 

[letdown427]

Originally posted by: spidey07

Originally posted by: JujuFish

Originally posted by: spidey07
Exactly. You can't take off if you can't move.

From the OP, the plane moves.

Fixed.

Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

Dear oh dear, so, so many quotable posts. It takes off. Simple. I honestly wish I could explain it to some of you 'doubters' face to face, just to see the moment when it clicks.

But, meh, this has been discussed before. Some think it takes off, some think it's a car. These threads should be locked, and a sticky placed on OT saying simply

"The plane takes off"

just to stop this from happening again, and again.

 

[PurdueRy]

Originally posted by: spidey07

Originally posted by: JujuFish

Originally posted by: spidey07
Not possible.

Impossible.

Read the post again. Then go back to rudimentary physics.

I suggest you do the same. Yes, the scheme in the OP would work... if we were talking about a car. Cars move forward by pushing off of the ground. Planes do not.

Fine.

I'll make it very simple for you...

If the plane moves forward a single inch then the conditions of the OP are not true.

I still can't believe we have boneheads thinking that it can. Back to school for them.

You sir, do not understand Physics.

I will say what I said to any other doubter. Draw a FBD...then get back to me.

 

[letdown427]

Originally posted by: spidey07
Fine.

I'll make it very simple for you...

If the plane moves forward a single inch then the conditions of the OP are not true.

I still can't believe we have boneheads thinking that it can. Back to school for them.

Just keep on digging that hole mate.

 

[JujuFish]

Originally posted by: spidey07
Fine.

I'll make it very simple for you...

If the plane moves forward a single inch then the conditions of the OP are not true.

The OP makes no such requirement.

Originally posted by: spidey07
I still can't believe we have boneheads thinking that it can. Back to school for them.

The irony.

 

[newParadigm]

Originally posted by: PurdueRy

Originally posted by: newParadigm

Originally posted by: CadetLee

Originally posted by: Evadman

Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

Now if there is enough headwind, even when the plane is visually stationary, it's possible that the headwind itself can push the plane up a bit but it would be very uncontrolled and will simply flip the plane over.

Quoted for posterity so we can all laugh later.

I think many of us (myself included) are misunderstanding the situation -- as a former student pilot (powered & glider) myself, I have an idea how these things fly..if you take this from the OP:

belt moves in reverse exactly as fast as the wheels move forward.

The wheels would necessarily rotate in direct proportion to the speed of the aircraft, which would leave me assuming that the aircraft is remaining in one position on the ground. Without a headwind, it couldn't take off.

What am I missing?

Edit: Which direction is reverse?

The q is worded rong it should say that the conveyor moves backward at exactly twice the forward speed of the AIRCRAFT.

"The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation." This language leads to a paradox: If the plane moves forward at 5 MPH, then its wheels will do likewise, and the treadmill will go 5 MPH backward. But if the treadmill is going 5 MPH backward, then the wheels are really turning 10 MPH forward. But if the wheels are going 10 MPH forward . . . Soon the foolish have persuaded themselves that the treadmill must operate at infinite speed. Nonsense. The question thus stated asks the impossible -- simply put, that A = A + 5 -- and so cannot be framed in this way. Everything clear now? Maybe not. But believe this: The plane takes off.

I don't think the question is worded wrong. In that quote they say the wheels are going 10 MPH forward. However, they are spinning at that speed but they are still only moving 5 MPH forward. This leads to 5 MPH treadmill speed and all is fine. It does depend on how you interpret the problem however.

After the conveyer starts moving the wheels aren't moving forward at all (Remember, the conveyor moves at exactly the same speed as the wheels). What he's saying, is that once the plane starts moving forward at 5mph, and the conveyor compensates, the plane will still be moving forward at 5mph (because the propulsion comes from thrust of hte engines and not powered rotation of the wheels). Therefor, the wheels will now be rotating at 10mph, and the conveyor will compensate, causing the wheels to again spin faster. This will keep going on ad infinitum, leading to the paradox. You have to phrase the question such that it refernce the speed of the body of the plane, not the wheels.

 

[PurdueRy]

Originally posted by: newParadigm

Originally posted by: PurdueRy

Originally posted by: newParadigm

Originally posted by: CadetLee

Originally posted by: Evadman

Originally posted by: deathkoba
You people are retarded. It will not take off as the sole lift mechanism (the wings) will not be getting any airflow. The engines only push the aircraft so that enough air can flow over the wings. Only then will the aircraft achieve any level of lift. I'm a private pilot with instrument license.

Now if there is enough headwind, even when the plane is visually stationary, it's possible that the headwind itself can push the plane up a bit but it would be very uncontrolled and will simply flip the plane over.

Quoted for posterity so we can all laugh later.

I think many of us (myself included) are misunderstanding the situation -- as a former student pilot (powered & glider) myself, I have an idea how these things fly..if you take this from the OP:

belt moves in reverse exactly as fast as the wheels move forward.

The wheels would necessarily rotate in direct proportion to the speed of the aircraft, which would leave me assuming that the aircraft is remaining in one position on the ground. Without a headwind, it couldn't take off.

What am I missing?

Edit: Which direction is reverse?

The q is worded rong it should say that the conveyor moves backward at exactly twice the forward speed of the AIRCRAFT.

"The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation." This language leads to a paradox: If the plane moves forward at 5 MPH, then its wheels will do likewise, and the treadmill will go 5 MPH backward. But if the treadmill is going 5 MPH backward, then the wheels are really turning 10 MPH forward. But if the wheels are going 10 MPH forward . . . Soon the foolish have persuaded themselves that the treadmill must operate at infinite speed. Nonsense. The question thus stated asks the impossible -- simply put, that A = A + 5 -- and so cannot be framed in this way. Everything clear now? Maybe not. But believe this: The plane takes off.

I don't think the question is worded wrong. In that quote they say the wheels are going 10 MPH forward. However, they are spinning at that speed but they are still only moving 5 MPH forward. This leads to 5 MPH treadmill speed and all is fine. It does depend on how you interpret the problem however.

After the conveyer starts moving the wheels aren't moving forward at all (Remember, the conveyor moves at exactly the same speed as the wheels). What he's saying, is that once the plane starts moving forward at 5mph, and the conveyor compensates, the plane will still be moving forward at 5mph (because the propulsion comes from thrust of hte engines and not powered rotation of the wheels). Therefor, the wheels will now be rotating at 10mph, and the conveyor will compensate, causing the wheels to again spin faster. This will keep going on ad infinitum, leading to the paradox. You have to phrase the question such that it refernce the speed of the body of the plane, not the wheels.

Like I said, it comes down to interpretation. I think he means the conveyor matches the forward velocity of the wheels, not the rotational velocity. But either way....doesnt' matter

 

[newParadigm]

 

[NaOH]

It FLYS
/thread

 

[newParadigm]

Originally posted by: StrangerGuy
The plane doesn't move forward relative to the air around it. So it cannot take off.

Man that was soooooo hard.

FVCK YOU!!! THIS THREAD MUST END NOW


YOU ARE A FVCKIN DUMBASS. THE PLANE DOES MOVE FORWARD RELATIVE TO THE AIR AROUND IT. IT DOES NOT MOVE FORWARD RELATIVE TO GROUND SPEED, BECAUSE THE ITEM PROVIDING THRUST SHOOT AIR AGAINST THE SURROUNDING AIR, AND ACCORDING TO NEWTON'S THIRD LAW (For every action there is an equal and opposite reaction.) THE PLANE WILL MOVE FORWARD AT EQUAL SPEED (minus frictional forces of course).

 

[newParadigm]

Originally posted by: sunase

Originally posted by: Vinfinite
Seriously those of you that says NO are total fvcken dumbasses, I can't believe it took 32+ pages just to discuss this

THE FVCKEN PLANE TAKES OFF

if you read the damn link and still don't understand, god you're freakin retarded

Text

READING COMPREHENSION FTW.

Okay so a plane is moving forward on a treadmill going backwards at the same rate as the wheels moving forward, a plane uses its JET ENGINES for propulsion, so WHO GIVES A SH@T about the wheels moving backwards? The plane pushes itself with its engines, the wheels are just there so the fvcken plane doesnt explode due to friction.

Read the damn article!

I'm just looking in, but I find it amusing that this poster didn't understand the article he cites. The article says the plane takes off when the belt speed matches the plane speed. It refuses to give an answer when the belt speed matches the wheel speed (as is stated in the first post of this thread), which it claims is impossible.

Yeah, b/c that imposible, and an improper statement of a question, so every inteligent poster assumed the OP realized this, and intended to say plane speed, not wheel speed.

 

[mchammer]

lol will this thread stop when there is one thousand posts?

 

[JujuFish]

Originally posted by: mchammer
lol will this thread stop when there is one thousand posts?

I almost don't want to see it end. It's kinda fun.

 

[JujuFish]

Originally posted by: newParadigm

Originally posted by: StrangerGuy
The plane doesn't move forward relative to the air around it. So it cannot take off.

Man that was soooooo hard.

FVCK YOU!!! THIS THREAD MUST END NOW


YOU ARE A FVCKIN DUMBASS. THE PLANE DOES MOVE FORWARD RELATIVE TO THE AIR AROUND IT. IT DOES NOT MOVE FORWARD RELATIVE TO GROUND SPEED, BECAUSE THE ITEM PROVIDING THRUST SHOOT AIR AGAINST THE SURROUNDING AIR, AND ACCORDING TO NEWTON'S THIRD LAW (For every action there is an equal and opposite reaction.) THE PLANE WILL MOVE FORWARD AT EQUAL SPEED (minus frictional forces of course).

Breathe in... breathe out... Calm down and enjoy the conversation. If you're not enjoying it, maybe you shouldn't be coming in if it bothers you that much.

 

[jagec]

Originally posted by: hellokeith
The plane's undercarriage attachments to the wheels are dependent on friction. Otherwise the plane on a normal runway would never be able to take off, or for that matter, brake effectively when landing.

Friction is necessary all throughout the system of a plane reaching a high enough speed to achieve enough airflow across the wings to provide lift. Those who are saying the plane wheel is freely spinning with no friction are not understanding that friction is required for the wheel to stay connected to the undercarriage.

Friction is necessary for BRAKING, and to keep the plane from sliding sideways. That's it. Unless you're referring to the frictional forces that holds the bolts of a plane together?

How, exactly, is friction necessary for the wheel to stay connected to the undercarriage?

Originally posted by: SampSon
The people who are trying to say the plane would not take off are simply relying on the semantics of the OP's post.

Even if you take the wording of the post at face value, the reality that the plane will not take off is still unrefutable.

No, they are MISINTERPRETING the original post. English is a flexible language. In order to understand it, one must (1)derive all possible meanings out of a phrase or paragraph, and (2)reject the ones that don't make any sense.

There are two interpretations to the OP. In neither interpretation is the plane held 100% still. And the second interpretation leads to a contradiction, so clearly it's out anyway.

Let's just put it this way: I hope the people who say it can't take off don't have any careers related to science or technology, since they demonstrate a woeful lack of ability to consider the possibilities hidden behind the problem, determine the real question being asked, and frame a reasonable answer

 

[thesurge]

Pretend you can fly, and you have a toy car. So you put the toy car on the conveyer belt (holding it and letting the wheels rotate) while you're flying above (saying the conveyer belt goes 10 mph backwards). Now if you start running above the conveyer belt (since you can fly) while holding the toy car down it will not SLOW YOU DOWN AT ALL (distracting other forces)!

hence the plane will take off.

 

[91TTZ]

Originally posted by: DLeRium
I think everyone fails to realize that in this discussion, we assume:

1) 100% static friction between wheels and conveyor belt
2) 0 friction in the axle so the wheels rotate freely (with 0 resistance)

Who said there was 0 friction in the wheel bearings?

 

[spidey07]

yeah, it's really quite funny to see all the people touting physics stuff when this has nothing to do with physics.

The plane simply cannot and will not move forward. It's impossible.

What's even funnier is seeing people try to apply physics to something that is physically impossible.

The conveyor can and will match the force of the thrust.

It's like telling people you can't divide by zero, and yet they still refute that you can.

 

[manlymatt83]

I still think that it will NOT take off. Anyone prove me wrong, but I don't understand how spinning the wheels would make it take off. There's no wind.

 

[Dessert Tears]

First, I need to mention these posts I found amusing. I didn't waste minutes of my life on this thread, I spent them for these posts.

Originally posted by: Squisher
I can't believe this thread lives!!!



Let's pretend the plane is flying at 200mph. I hang out of the plane and attach a treadmill under its wheels and cause the wheels to spin at 200mph.

WILL THE PLANE FALL OUT OF THE SKY??????????

Originally posted by: PurdueRy
NOT AS LONG AS ITS ON TEH TREADMILL!!!!!1111one!!11

:evil:

Originally posted by: waggy
ok this thread is full of stupid post but this one takes the cake! how could it fall out of the sky ITS ON A TREADMILL! it will just sit on it! duh! :evil:

I've read a lot of this thread, and I regret it, but I haven't read every post. If I repeat something already posted, I apologize.
OP:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.

And if it matters, it's a nice sunny day and you have good tires, so you get perfect traction on the belt at all times. Your plane also happens to be very powerful and you can give it as much thrust as you like, but the source of thrust is at the back of the plane so it never provides airflow over the wing.

Does the plane take off?

Read the post and make conclusions:

1. Take sentence 2 and sentence 4, clause 2 to mean that the belt can somehow hold the plane immobile relative to the true ground. I personally disagree with this reading, but it is the basis of most "No" posts.
2. Sentence 3: infinite friction between wheels and belt.
3. Sentence 4, clause 1: infinite available thrust.
4. 1 + 3 -> Belt can move infinitely fast, and wheels spin infinitely fast.

Then add the following:

1. Friction in wheel bearings is non-zero. Otherwise, there is no path to impart force or energy from the belt to the plane body.
2. Assume that the friction in the wheel bearings is small.
3. Assume non-zero friction between the belt and the air.
4. Assume that the belt has a much larger surface area than the sum of the surface areas of the wheels.

I submit that it is possible to take off in this situation. The belt moves at a ridiculous speed to oppose the unlimited thrust, moving enough air at a high enough rate to create the windspeed and thus lift required for take-off.

 

[mugs]

Originally posted by: mjuszczak
I still think that it will NOT take off. Anyone prove me wrong, but I don't understand how spinning the wheels would make it take off. There's no wind.

The wheels have nothing to do with making it take off, the fact that the plane moves relative to the air (and relative to the ground next to the treadmill, and relative to the treadmill for that matter) makes it take off. The treadmill can't keep the plane from moving.