A plane on a conveyor belt

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jas72 said:
what the fact that the wheels are connected to the ground providing traction allowing the plane to move forwards whilst connected to the ground?

for the plane to move forwards it would have to provide more forward thrust than the converbelt is providing backwards movement no?
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The point is that the wheel's don't provide any traction, they simply act as something on which the weight of the plane can be transferred to as it slows down or transferred from as it speeds up. The plane moves by drawing air into its engines.
 
AFAIk the only thing that would suggest it would keep from moving would be the weight and of the plane acting on the ground..

theres a model airplane vid and you can see it does move forward but only a lil bit
 
jas72 said:
the wheels are connected to the ground providing traction allowing the plane to move forwards
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That's wrong. The plane doesn't need traction to provide forward thrust. It provides thrust by accelerating air in the opposite direction.

You're imagining it as a car, which provides thrust by spinning its wheels.
 
jas72 said:
what the fact that the wheels are connected to the ground providing traction allowing the plane to move forwards whilst connected to the ground?

for the plane to move forwards it would have to provide more forward thrust than the converbelt is providing backwards movement no?
Click to expand...

It doesn't matter if the plane is floating using some force field, the plane will take off because the conveyor belt is moving at the same speed as the plane but in the opposite direction. The conveyor belt is not moving at the same speed as the wheels, the wheels are there to allow the plane to move and so they are a free following entity. The plane doesn't actually use the wheels to provide power they use the trust from the engines.
 
jas72 said:
what the fact that the wheels are connected to the ground providing traction allowing the plane to move forwards whilst connected to the ground?

for the plane to move forwards it would have to provide more forward thrust than the converbelt is providing backwards movement no?
Click to expand...

have you ever done mechanics maths?
Basically the aeroplane isnt a 'particle', the treadmill isnt acting backwards on it and the engines aint acting forwards.

The treadmill act backwards on the wheels, which for the sake of arguement(so we dont have to get anal) have 0 friction in the pivot(is that the right word? forgot) and 0 friction against the ground, therefore the wheels just spin while the treadmill does too.

But then the engines and the rest of the plane are another particle, there is forward thrust caused by the engines, with only air resistance pushing backwards, whereas there are no backwards or forwards forces on the wheel/treadmill, just things spinning..freely.

Therefore the engines are going to move the plane forward, and the wheels are going to move at the speed of treadmill(making them stationary) THEN the speed of the plane(meaning the plane moves along the treadmill)

Get it now? Its the fact that people are thinking of the plane as 1 particle, not the fact the wheels are infact a seperate entity in the mechanics/physics terms. Blame GCSEs tbh :)
 
Durzel said:
I realised "cretins" was probably a bit harsh afterwards :p Still, you have to be pretty dense to figure that a plane takes off using its wheels.
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People are used to cars and the fact that wheels provide friction, so they don't instantly realise that the wheels on a plane exert very little friction on it. It's not stupidity. If you told them the wheels aren't fixed to the plane like they are in a car, they would get the right answer everytime. Just because people don't understand special relativity doesn't mean they are stupid even though the concepts are easy to understand, it's just because they don't deal with it in their everyday life.
 
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