Earth spinning

Neodude, think of the wheels being trolley wheels okay?

Stick that on a treadmill which is moving at 10mph - okay?

Tie a rope to the front of the trolley, and hold it. The wheels will spin freely, and the trolley will remain stationary.

Pull it, and the trolley will move towards you, the speed at which the wheel rotates will increase, yes? But the trolley will have moved.

Put a jet engine on it, and it will move forwards.
 
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neodude said:
Probably yes.

The question comes from the original question posted by Borden...

"If an aeroplane was sat on a treadmill that was moving in the opposite direction at the same speed the wheels were moving, would it be able to take off?"

Which is the one I'm arguing against.
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Which does not specify the the reference point for the wheels, so you have invented a convoluted definition to try and argue against, congratulations. Except you are still wrong, because the situation you have constructed requires that the plane actually moves in the first place, or that the wheels never turn, a speed of 0 is the only point at which your construction works, hence it is fundamentally broken and a nonsense.
 
neodude said:
Not if the treadmill is set to exactly match the wheelspeed.
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It's not possible to make a treadmill match wheel speed though.

The wheel speed is not created by the plane, the wheel speed is created by the difference in motion between the plane and the surface it's moving across.

If you change the speed of the surface the wheels are touching, the speed of the wheels will change.

Regardless of how fast or slow the treadmill is going, powering the plane will make it move forward, and lift off as normal (provided that the wheels are allowed to move freely).
 
neodude said:
hence breaking the conditions of the question.
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Where is this exact question that you seem to have to follow exactly?

Was it written down somewhere as a definitive thing? Or is it just the set of impossible to meet rules that you've decided to stick to?

As far as I know, the myth is just "A plane cannot take off while sitting on a conveyor belt moving in the opposite direction." Which isn't true.
 
you are assuming infinite friction between the wheels and the treadmill. without that irrespective of how closely the speeds were matched the wheels would slip on the treadmill owing to the force of the jet.

Your special version of the question isn't arguable because it doesn't work in any situation. There's no point in just stating over and over again that the treadmill exactly matches the wheelspeed because it couldn't ever happen.
 
neodude said:
Which would require the wheels to be moving faster than the treadmill and hence breaking the conditions of the question.
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ok i see where you are comming from... half of us as thinking in real terms, the other's are talking about hypothetical situation in which there is a made up rule that cannot be broken (but would be broken in real life) IE the rotation of the wheels...
 
orderoftheflame said:
Where is this exact question that you seem to have to follow exactly?

Was it written down somewhere as a definitive thing? Or is it just the set of impossible to meet rules that you're sticking to?

As far as I know, the myth is just "Can a plane take off on a treadmill?"
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Yep. That's the original myth. And I agree with the majority. The plane will take off. The reason for the pages of arguments against me are due to the question posted by Borden...

"If an aeroplane was sat on a treadmill that was moving in the opposite direction at the same speed the wheels were moving, would it be able to take off?"

Where I stated that in this particular case it would be impossible for the plane to move.
 
edscdk said:
ok i see where you are comming from... half of us as thinking in real terms, the other's are talking about hypothetical situation in which there is a made up rule that cannot be broken (but would be broken in real life) IE the rotation of the wheels...
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Yep. The question is complete nonsense and has no basis in reality. I agree with that. But within the confines of the question the plane cannot move.
 
neodude said:
Where I stated that in this particular case it would be impossible for the plane to move.
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You are still wrong tho :p The thrust of the jet engines is independent of the wheels and the treadmill, the jet engines always win.
 
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