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Plane Problem

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its just a theoretical question, the lenght or friction doesnt matter here. will it fly or will it not, thats the question.

too bad i have to sleep now, or ill be a zombie at work tomorow. i would have loved to see explained how the hell 600 mph can disapear.

the formular 600-600 is just funny.
he said that plane accelerated (or moves) with 600mph and the mill goes with 600mph in the oposite direction and also saying the weels spinning with 600mph.

in my world PlaneMovement=600 + MillMovement=600 equal WeelSpin=1200.
The wheels are spinning at 600 MPH because the treadmill is moving 600 MPH in the opposite direction. The plane, and the platform everything is on is not moving at all.


600 MPH forward movement of the wheels
-600 MPh movement of the treadmill going the opposite direction.
-----
0 MPH movement of the plane.

If the wheels were going 1,200 MPH the treadmill would speed up to 1,200 MPH to compensate. So again, the plane would not move forward.

Before anybody stars in about the engines. I know they are what is creating the forward movement of the wheels, buy they are being nuetralized by the reverse movement of the treadmill on the stationary platform. Niether the plane, or the platform are actually moving. Only the wheels and the tread are.
 
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If the wheels were going 1,200 MPH the treadmill would speed up to 1,200 MPH to compensate. So again, the plane would not move forward.
Misread the question did we? The treadmill is moving as fast as the plane, not the wheels. If the plane is moving 600 mph then the wheels move 1200 mph and the treadmill moves 600 mph. But by your logic the plane will never move, therefore the treadmill will never move, therefore the wheels will never move, since the treadmill is moving relative to the plane, not the wheels.
 
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this movie is taking awhile.

Plane = Car.

This is my thesis:

Car pushes against treadmill for forward motion, treadmill moves back, cancelled cars pushes.

Plane pushest against AIR for forward motion, treadmill moves back and does bubkiss to the plane. Plane goes forward and flies away.



The plane is never moving forward. Be it pushing air, the treadmill, water, or magical fairy dust.


The plane stays in one spot. Thus it will not take off. The plane can't move forward, because it's forward motion is cancelled by the treadmill.


Treadmill starts at zero. Airplane starts a zero.

Airplane gives throtlles up. NORMALLY, this would make it go forward, and we'd begin to have lift. In this case, though, the plane does not move forward. It sits in one spot because of the treadmill. No air is moving over or under teh wings, only through the engine.


Whoever said it first was right, we don't have enough information in this problem to fully work it out. But assuming known values from the real world, it would never work.
 
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The problem posed doesn't give enough detail.
It has this magical treadmill which can match a plane's acceleration but does not say whether the plane's wheels are perfectly frictionless. It doesn't say how long the treadmill is. It is basically a ****ty question.

Doesen't matter, its just a hypothetical, not ever ment to take such factors into acount, the question is as simple as it is posed, would the plane take off on that treadmill?

The answer is: no, the plane is not developing any lift with its wings, and therefor cannot take off.

And Ruprecht, you asked:
but when the plane is moving with 600mph and the mill does also move 600 mph in reverse, and the weels spin only 600 mph, where did the remaining 600 mph go?

There are no remaining 600 Mph, the treadmill is moving backwards at 600 Mph, and so are the wheels (remember, planes taxi by the thrust of their engine(s), the wheels are not powered in any way, so the wheels will follow the treadmill), and the engines thrust are propelling it forward at 600 Mph, therefor, the two counter balance eachother, and the plane does not actually move.

There are only two cases of "600 Mph", the treadmill and the engines thrust, not three, as the wheels are not powered.
 
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If there is no friction in the wheels, I'm pretty sure the plane will move forward and therefore take off, because the only force acting against it will be air resistance, which is of course far too low to prevent its acceleration. It's just like having a plane that doesn't touch the ground at all, but just sort of... levitates above it.

Yes.

I love you.

edit: Fun fact.

The reason why I'm so angry about this is that it has come up before while I was helping a friend teach ground school years ago and they two 15 year old ****head wannabe pilots were arguing pretty hard about it with the rest of the class the instructor and myself until they were blue in the face.

So I failed them on theory of flight section (0), which they actually failed anyway (40 % or something - 75 was a pass). Never showed up after they got their tests back. Take that ****ers.
 
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The plane can't move forward though because the tread mill is compensating by moving backwards at exactly the same rate. They are both on a stationary platform.

A jet car would react the same way. As the jet car tries moves forward, the tread moves backwards at the same speed. The platform they are both on does not move at all! Therefore it can't move forward because it is being pulled back at the same rate. If it trottled back and the treadmill did not. It would shoot off the back like someone who stops running and falls off. If it throttled up anfd the treadmill did not. It would move forward. However since the tread mill always compensates by going the exact same speed. Just in reverse. The car/plane never actually moves. It only mantains it's position on the tread.

I don't know how to make it any clearer. If you don't understand what I'm saying by now. I can't change your mind. I've basically been repeating myself for the past, I don't know how many, posts.

BTW, I came up with the frictionless wheel thing on page two. That is not in the problem though. So it's not part of the answer.
 
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When object1 on the ground (object2) is pushed by a force1 that acts ONLY ON OBJECT1, object2 pushes back with friction. If object2 is moving in the opposite direction, friction with increase. However, if fricition is, for whatever reason, reduced to zero, there will be no force pushing against object1 and it will therefore accelerate equal to the force1.

IN THIS EXAMPLE, PLANE=OBJECT1 AND GROUND=OBJECT2. THE HYPOTHETICAL WHEELS REDUCE FRICTION TO ZERO. THE FORCE1 ACTS ONLY ON THE PLANE. THE WHEELS ARE NOT THE SOURCE OF FORWARD ACCELERATION.


END OF THREAD. STOP POSTING. GO TO BED. I KNOW I AM.

 
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The Wheels Are Not Linked To The Plane!!! They Spin Independently!!! The Engines Will Push The Plane Forward!!! Its not like a car where the engine turns the wheels. The wheels are like casters on a rolling chair.


You're right. The wheels are unpowered completely. HOWEVER, the plane never will move forward, because the net forward force of the plane is cancelled by the net reverse force of the treadmill. No movement means no wind. No wind means no lift, which means no flight.
 
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big words!!!




You'd be right, but the wheels have their own friction. The plane can't get moving forward because of that. Since it can't get moving forward, it can't generate lift.


If you assume no friction in the wheels, ok, the plane would be able to take off. If you assume friction in the wheels, it wouldn't. Bad problem with two possible outcomes.
 
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Tak, we have to assume there is no friction in the wheels. Otherwise you cannot answer the question. There may only be a tiny amount of friction in the wheels and it'd still take off. But what if friction is high? The wheels would probably overheat and fail and the plane would crash and we'd all die. It's a totally hypothetical question so you have to take all parts of it hypothetically unless stated otherwise.

Someone please lock this thread. For the sake of my sanity.
 
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Tak, we have to assume there is no friction in the wheels. Otherwise you cannot answer the question. There may only be a tiny amount of friction in the wheels and it'd still take off. But what if friction is high? The wheels would probably overheat and fail and the plane would crash and we'd all die. It's a totally hypothetical question so you have to take all parts of it hypothetically unless stated otherwise.

Someone please lock this thread. For the sake of my sanity.


No, you'd die, my ass would never get on the contraption to begin with! :p


I'm not assuming no friction unless told to, which the problem didn't do. Even with low friction, that friction will increase as the motion does. So you'd have to have such a miniscule amount of friction on the wheels so that the plane can reach a speed where it is able to lift off before the friction from the wheels becomes enough force that it cannot achieve critical velocity.


The difference lies in the assumptions, and I stand 100% by my 'no' vote assuming known values. If the equation stated no friction on the wheels or if you're in the camp assuming no friciton, then the answer is yes.
 
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Don't lock until moz posts vid plz

Tak so totally just changed his story 100% and completely. We've assumed no friction all along. Of course if real world measures applied the plane would never take off because the wheels would catch on fire from turning 1200 mph faster than they should, and no the plane would not take off, but it's assumed no friction because it's a thought experiment, not real world.

Real world, you'd never get a treadmill that could keep up with a plane. So bleh.
 
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Look guys, its not at all that complicated, its a simple "problem" ment to remind people that what makes a plane fly is lift, not engine thrust.

Wheels, friction, the fact that the treadmill is impossible to make and that the landing gear would surely collapse, none of it matters in answering the question.

The premise is simple, the plane is driving 600 Mph on a treadmill, but is actually going 0 Mph compared to the world around it.


And the answer is a resounding: NO! the plane is not genrating lift, and therefor will never fly.
 
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