Elwood,

WE ALREADY KNOW THAT SLOWPLAYRAY SCREWED UP THE INITIAL QUESTION, AND THAT THE WHEEL ROTATION CAN'T EQUAL CONVEYOR BELT SPEED AND STILL ALLOW THE PLANE TO HAVE THRUST. NO ONE CARES ABOUT THAT ANYMORE.

I HOPE THE CAPS WERE HELPFUL IN YOUR UNDERSTANDING

What I have learned from this thread is that aircraft carriers should have treadmills on them instead of tailhooks/wires. If the plane is coming in for landing @ 200 mph, simply run the treadmill @ 200 mph the opposite way. As soon as the plane touches down, it will instantly stop.

Very helpful. Who, then, is arguing that the plane won't take off (absent the controvery about the wheel rotation)??? If "no one cares about that anymore" then why is this thread a couple of pages long as that is the only bit of contention?

Go back to page 1, where this was already cleared up. Your response had nothing to do with what you quoted.

The only trick to this hypothetical is that people think the planes wheels are used for propulsion. That's it. It isn't that complicated.

You are wrong here. Pretty much everyone who initially says the plane wont take off is saying so because they get confused and in their mind they picture this airplane like a car, and its hauling ass forward but not going anywhere cuz the treadmill is spinning just as fast in the other direction. So they say it wont fly because there is no air moving over the wings since the plane is stationary.

Its only after they are told they are wrong, they come up with some ******ed wheel argument and skipping and sliding and all that other dumb **** come into play, and they cling dearly to that argument.

The wheels, the cockpit, the tail, the entire plane is all one piece and its all going forward at the same speed. The wheels might be rotating a ****ton, but their forward speed is exactly the same speed as the plane, because they are attached to the plane. All these other arguments are just to save face, or just to be trollish and difficult.

I agree a lot of people got confused. But generally it's because of the wording with the wheel speed. If the plane hits 200 MPH it will take off. I don't understand why if we already know as the set up to the problem, that the plane is moving forward at a given speed relative to the ground, that it's even an interesting problem.

I know what you're saying. I think your explanation is a bastardization of the language (though clearly not the intent) of the hypothetical. You hold the "speed" of the wheels to a completely different standard than you hold the "speed" of the treadmill in order to satisfy what you thought was the answer without doing a careful reading of the question. It's the same mistake I made (as my very first post in the initial thread asked why this was any different than taking off on ice) when I initially read the question. Your notion that others are trying to save face (while you bastardize the language of the hypothetical) is laughable.

How am I bastardizing the wording? Im not holding the speed of the wheels to any different standard than the speed of the treadmill. The wheels go forward at 100MPH, the treadmill goes the other way 100MPH, where exactly am I bastardizing anything?

The speed of the wheels you are saying is in relation to a stationary object.
Is that the case with the treadmill???

sure why not. I can play the being difficult game too. No where in the original question do they say its the converybelt rotating, so clearly they must mean that the converybelt as a whole is moving in the opposite direction. Or maybe they do mean its all about the rotational speeds, but which point on the plane's wheel should use for our velocity?

Its like Daryn said, its common sense. Anyone who has any, knows exactly what the question means. Its not confusing. If you put a plane on a treadmill, can it take off?

And I'm not arguing about the "meaning" of the question (so long as you ignore the words.) But don't get all condescending when you have to twist the plain meaning of the words to fit your answer. You assume that speed for one rotating object means speed with relation to a stationary object and the same word in the same sentence with another rotating object means rotational speed. That's fine. I readily concede that's what the question meant to convey (no pun intended.) It just isn't what it said.

I love how you first complain about rationalizing and now you have the conveyor belt driving across the runway.

And anyone with a fourth grade education knows that's not what the question said. Your answer is absolutely right for the question that wasn't asked. Had it been asked in the common sense way (that you stated) there would have been very little disagreement.

lol, yes there would. There would be the exact same disagreement. Go ask people in the common sense way and youll get the same incorrect responses, just less stupid arguments when the correct answer is explained to them. Its got nothing to do with some BS argument about a poorly worded question, and everything to do with the fact people dont think about the problem in the correct way.

hell just go watch the mythbusters preview clip, even the ****ing pilot says the plane wont take off, and hes sitting there watching how the experiment will take place

Somebody on another forum dids some maths and figured that to stop the plane the conveyor belt would have to be spinning at like 60 times the force of the engines.

60x|=x, bitches. I'm drunk but my 9th grade physics skills are still solid.

Stolen from another forum:

This is the whole problem. Just remove this phrase and instead say "The conveyor belt is designed to exactly match the speed of the PLANE, moving in the opposite direction" and then people can argue over the actual meaning of the problem

Everyone who understands why the plane will take off also realizes that the wheels will be spinning faster than the treadmill is moving. You should also realize what the main point of the original idea was meant to be.

If the conveyor belt is switched on while the plane has no forward thrust, then the plane will move backwards (relative to ground). Now the pilot adds thrust until the plane has 0 velocity (relative to ground). This would be the point of equilibrium.

In a frictionless hypothetical, this point of equilibrium is fixed, I think? ie If the conveyor belt is sped up, would the pilot need to increase thrust to keep 0 velocity (relative to ground)? I am not sure, but I think not.

So, if the point of equilibrium is actually fixed, then any additional thrust would add +ve velocity and propel the plane down the conveyor belt until lift-off.

If you add in friction (wheels, wind-resistance), then the point of equilibrium would change, but wouldn't it eventually be overcome?

Isn't inertia one of the main forces at work here?

To make a plane take off, it requires an upwards force. The upwards force is created by the wings when they move forwards by the aerofoil concept. If a plane is moving forwards at a great enough speed, it takes off. So is this plane going to move forwards fast enough?

Lets pretend I'm running on a treadmill, lets pretend I now have aeroplane wings, lets now also pretend I have a 4500 horsepower turbine engine on my back. I turn the engine on, where am I going to go?

The treadmill is going to go really fast, but who gives a toss, I can run really fast because actualy I'm a plane with wheels on a conveyor belt.

Any questions?

I have a degree in mechanical engineering and another in computer science if that helps my credibility.

Inertia has nothing to do with anything here. Equilibrium is achieved when all the forces are equal on an object, this is not true in the situation you mentioned because the engines will be pushing the plane forwards with only a relatively tiny amount of friction pulling it back. Once you get to the point of dynamic friction an object will begin moving.

Remember, ignoring friction, this plane is going to be like it's floating. If you could place a plane on a friction compensated ramp, and there was no friction between the wheels and the plane, I could push the plane around with my pinky, just like the thrusters launch the plane into space, but oh wait, they do that anyway

This did NOT get anywhere near enough love, I'm still laughing after 10minutes.

what are you even talking about? i noticed you had replied after me and told you to read my post above. you're basically making next to no sense in this thread and this post isn't exactly helping your case.

by the way a big problem here is people who know nothing about physics are trying to equate angular velocity of the wheels with the linear velocity of the treadmill. that might work in the example of a car on a treadmill, because the car's speedometer automatically converts the wheels' angular velocity into a linear velocity (for that specific automobile), but there's no such equivalent on a plane.

it's funny elwood accuses alobar of "twisting the problem around" when in fact it is elwood that is twisting it a bit by interpreting the problem specifically as: "the conveyor belt moves with a linear velocity equal and opposite to what the wheels' linear velocity would be if they rolled along a surface with no slipping"

you can't just say, "ok the treadmill goes 100 mph in one direction and the wheels go 100mph in the other direction" unless the plane is also going 100 mph in the other direction.

basically this whole thread is a tiltfest.

the other thread was also a tilt fest, especially since all the smartypants kept saying there is no relationship between the wheel and the plane.

clearly, if the wheels do not slip, there is a forumla relating angular speed of the wheels, the speed of the treadmill (compared to the ground), and the speed of the plane (compared to the ground).

correct you could relate all of those variables to each other very easily. at the end of the day the plane takes off, no matter what the wheels are doing.

i'm actually starting to wonder if the plane could take off even if the wheels were locked in place. sure a fire might start up from all the heat produced by friction, but it would probably take off eventually if they gave it enough thrust.

Let's put it this way: You put a car in neutral on a treadmill. The treadmill gets going and the speedometer on the car reads 120 (though the car isn't moving forward.) Someone asks you "what was the speed of the wheels?" Are going to say with a straight face that you would respond "0 mph because with regard to a stationary object the wheels weren't moving forward." Or would you answer like every other person on the planet that the speed of the wheels was 120 mph?

Why would you even wonder that? Of course the plane could, though that isn't what the plane language of the question is asking.