So, will it take off?Follow

That's the crux of it. The plane doesn't "hover" or anything, it's just that the thrust from the engine propels the plane forward and all the conveyor belt can do is make the free-spinning wheels spin like mad as the plane goes forward as usual. In seconds, the plane will either be off the belt and moving as usual or else you have one hell of a long belt.

That's not implied at all. It clearly says that the conveyor moves at the same speed as the plane but in the opposite direction. Nothing about neutralizing the plane's forward motion is implied or inferred. That's just an assumption that you are, erroneously, making.

The very fact that the question asks if the plane would be able to take off implies that the planes forward motion is being affected. The question is designed to make the reader assume that forward motion is being prevented and come to the incorrect answer that the plane wont take off. The reader does not come to that incorrect answer out of some flawed understanding of what allows planes to take off, but based on the assumption that the conveyor apparatus described in the question must be intended to prevent the plane from moving forward.

I've have not yet heard a single person say that the plane wouldn't take off because of some magical effect of the conveyor belt gluing it to the ground or something. Every single person who gets the answer wrong believes that the conveyor belt somehow prevents the plane from moving forward, thus preventing it from recieving airflow over the wings, thus preventing lift, and thus preventing take off. Now, we can either assume that it's a total coincidence that they all think the effect of the conveyor belt described in the question prevents forward motion of the plane, or we can assume that the question is written specifically to make them think that.

It's one of those annoying questions that don't really test people's understanding of how something works, but instead tricks them into thinking that the conditions being asked about are different then they really are. You see these kind of questions on IQ tests all the times (actually, real IQ tests don't, but the silly Mensa style ones are chock full of them). A rational person would assume that the only purpose the conveyor belt serves is to prevent the plane from moving forward. If one does not carefully read the question, he'll likely come to exactly that conclusion (just as everyone who answered "wrong" did). After all, why else is the conveyor belt there? Why this kind of question is annoying is because it's common in those silly "see how smart you are" tests, in which it's not really testing knowledge or original thinking or anything, but seeing if you can figure out the trick in the trick question. Get's boring after awhile. Doubly so since they're usually pretty darn predictable.

the lift of an airplane is created by wind flowing over the top of the wing.

no wind flowing over the top of the wing, no lift.

however......given enough thrust vs weight ratio, the aircraft could concievably launch like a rocket as opposed to lifting like an airplane. f-18,s for example can go verticle on thrust alone. but even they need wind over the wing for directional controll.

sooo, plane no, rocket yes.

You know why helicopters fly? They're so ugly the ground repels them!

It's a common misconception about airplanes that the propeller on the front is what makes the airplane go forward. that's not what it's there for at all. It's simply there to cool of the pilot. becaue if it stops unexpectedly mid flight, the pilot sure starts sweating a whole lot!

The plane is moving but not covering any distance. Lift off will be achieved ( depending on load and style of aircraft) at approx 187 mph assuming that the tabs are down of course. My answer is yes.

The wheels are there just to keep the plane off the ground when it isn't flying.

So as long as you have a 'conveyor belt' long enough that allows whatever propulsion device you are using i.e. jet/propellor to gain enough velocity for flight than sure, it flies. The only difference between having the belt and not is the wheels are spinning faster and everyone around you is wondering why the hell there is a conveyor belt on the runway.

But, and as I think the question somewhat implies, you cannot take off in shorter distances with a conveyor belt running under the plane.

Unless, of course, the conveyor belt runs in the *same* direction as the plane and allows it to get to flight velocity quicker. Like an aircraft carrier.

DK

Step back, if you will, for a moment. Picture yourself as an observer of this plane and the conveyor belt. You are standing adjacent to the plane, but not actually on the belt. The plane's engines fire up, the prop or afterburners begin to apply thrust to the airframe. The conveyor belt moves in perfect synch with the power of the engine, and the wheels of the aircraft begins to move.

But the aircraft isn't moving forward or backward in relation to you. It's not flying, it's just making alot of noise and burning up old dinosaurs.

You're just standing there picking your nose watching all of this, which the pilot interprets as the signal to go to full power. Boom! (or vrrrrrrrrrrrrrrrrrr in the case of a prop driven plane) Afterburners kick in, the conveyor belt speeds up, and huh! The plane still isn't moving forward or backward. You scratch your a$$ 'cuz it's itchy, which the pilot interprets as turn left, which he does since he obeys all FAA rules and regulations and veers towards you, leaving the conveyor belt. ZOOOOOOOOOM! The plane's engines now have got some purchase against the ground and rapidly moves forward-- something it hadn't done up until this point. Just as he runs you over, the plane exceeds stall speed and lifts off leaving you either with tire treads across your forehead, scorch marks from the 'burner, or slashes from the prop chopping you in pieces.

Now do you understand why the plane didn't fly on the conveyor belt?

Totem

And the stork brings the babys.

/sigh

Ok, let's go through this one step at a time. I will pause to let each of you agree or disagree with me as to what is happening. This way we can come to terms with what is happening.

Assumptions: There is a frictionless conveyor belt that somehow has the means to detect and match any movement of the plane that sits on its surface. That plane has an engine(s) that only provides lift to the wings by providing forward thrust. No slope is present, and no wind is blowing.

We all agree so far?

Totem

Point taken, Eske.

Ok, the engines light, power is applied to the motors, the plane's wheel begin to move. The conveyor belt matches the plane's wheel speed. There is no relative motion to the ground beyond the belt.

Agreed?

Totem

I am making the assumption the plane is the driving force here, not v.v. Once the plane's engines are lit and the brakes released, there is thrust which in turn moves the conveyor belt via the wheels. The plane is not moving.

Totem