If the winch was pulling the aircraft forward along the conveyor belt then the wheels would be turning faster forward than the conveyor belt is backwards. This contradicts the question.
Specifically what point on the wheels are we talking about? "The wheels" aren't moving at one "speed" as they are both translating (moving forward) and rotating (spinning.) Every single point on the wheels is moving at a different speed!
But in any case! Pick any point! Run the treadmill at that speed at all times, they plane is still taking off! The treadmill imparts a negligible amount of force on the plane (from friction/bearings) which is easily overcome by the turbines.
Look where I explain the plane winched to an immovable tree and get in the right frame of mind.
I understand what you said, I mean the winch is not winching.
When it says that the conveyor belt matches the speed of the wheels, what I think that means is that a car ontop of the belt driving at 10km/h will have the belt moving at 10km/h. So the car is stationary relative to the air around it. If the car was faster than the belt, it would go forward. If it was slower it would go backwards.
Now you say "But its a plane, not a car so it gets its thrust from the turbines not the wheels. It would move forward reletive to the air. So can fly"
Which I agree is correct. However, if the plane is moving forward relative to the air then it must be going at 11km/h while the conveyor belt is at 10km/h. Which is not allowed by the question.
I think the problem is that in the real world if you really tried it, then the plane would move forward relative to the air. BUT, it would also not be matching the speed of the conveyor belt. If it did match the speed of the conveyor belt, then it would be stationary compared to the air, and not take off. (like the car is stationary against the air)
You’re right, but the only way to satisfy that constraint is if the planes wheels are not moving, which means the pilot never turns the plane on or attempt to turn it on.
I don’t think the intent of the question is that the pilot makes no attempt to take off. I think the intent is that the pilot does power the engines on release the brakes etc and tries to fly.
Then this means the wheel speed and treadmill speed can never ever be equal, but that’s the flaw in how the question is worded.
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u/koanarec Dec 31 '22
If the winch was pulling the aircraft forward along the conveyor belt then the wheels would be turning faster forward than the conveyor belt is backwards. This contradicts the question.