re: Can this 747 take off?

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Yet you said the wheels were motionless

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because...

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he plane would have to move for the wheels to start moving. Once moving, the treadmill would not be bale to stop the plane's initial movement, as the only contact the treadmill has with anything on the plane is the wheels, which are not part of the plane's "drivetrain."

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So the wheels would not match the treadmill speed exactly, as in the question?

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They both would be at zero RPM. ETA If we are staying within the constraints of the riddle.

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RPMs is a really bad way to measure wheel speed and the speed of the conveyor belt here.

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0 is 0.

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And the only way for the wheels to remain completely stationary is for them to be completely locked which is not indicated in the hypothetical.

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But to match the wheel speed exactly, the only way the plane doesn't move is if they are both at 0.

ETA And I say 0 rpm, because the wheel would technically have a speed in the horizontal when the thrust of the plane overcame the force of friction and moved the plane

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Or if they both begin moving at the exact same time.

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The wheels would have to be part of the drivetrain for that to happen with the plane not moving.

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Just like a car until it lifts off

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Nothing like a car actually, unless the car is jet powered

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Correct, which is why the hypothetical is broken. An instantaneous feedback loop like contemplated in the hypothetical is never triggered because the only way the conveyor belt moves is if the wheels move, but the wheels can't move because it means the wheels exceeded the speed of the conveyor belt.

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I think the wheels and belt would be both be at 0 and the thrust of the plane would just drag the plane across the belt. I am 100% confident the plane will move ETA: unless the magic belt generates more friction than the plane generates thrust, then the plane doesn't move.

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It took you 20+ pages to finally understand the magic treadmill. Well done sir

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Nowhere in the constraints of the OP is the friction discussed

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Nowhere in the constraints of the OP is the friction discussed

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True.. It only says the conveyor belt is designed to exactly match the speed of the wheels.

This is such a stupid question how it's worded, and is requiring assumptions to be made.




If the plane's engines are on, then it's going to make the plane go forward since the plane's power is simply to push the plane forward, with the wheels similar to a car being in neutral.

WHen they say the wheels and belt are the same speed, i assume what they mean is that same distance is being displaced by both the wheel and the belt as they move simultaneously, thus the plane doesn't actually move horizontally. I guess that's there way of saying ignore other forces like friction and gravity. In actuality, this would require a lot of physics to figure out how both the wheels and belt can be at teh same speed.
This is no different than if you put a toy car on a treadmill and put your finger behind the car and turned the treadmill on. the wheels will turn, and the belt will turn, but the car won't move b/c you're applying the force along the x-axis onto it, same as the planes engines.

If the plane isn't moving along the x-axis, then air isn't passing over and under the wings, and if that isn't happening, then it's impossible to achieve lift.
I'm assuming the way this stupid question is posed, i am too assume the plane will not actually move along the x-axis, even though in reality it woudl be extremely difficult to achieve this.