Earth spinning

Nate--IRL-- said:
Why ... just why? Let the thread die.

Nate
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Because I'm trying to reduce the number of idiots in the world who don't understand basic physics or aircraft... And by god it frustrates me how many non-sensical posts there are on the thread...

You're right, it would be good to let it die, but that isn't going to happen any time soon I'm sure...:D
 
Penfold101 said:
Because I'm trying to reduce the number of idiots in the world who don't understand basic physics or aircraft... And by god it frustrates me how many non-sensical posts there are on the thread...

You're right, it would be good to let it die, but that isn't going to happen any time soon I'm sure...:D
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Good on you :) I haven't got the patience lol :p
 
As soon as the planes engines exert any form of thrust (no matter how small but sufficient to make it move in its usual environment) the plane will start to move regardless of what the treadmill is doing underneath it.

The wheels on a Jet aren't driven, so the treadmill can never under any circumstances cancel the thrust of the planes jets out, their rotation will simply speed up indefinitely as the plane moves forward, only slowing down once the plane takes off and has left the treadmill. This is because the thrust of the plane is not from the wheels.

Because the wheels don't drive the plane forward, you can remove them from the experiment, so Imagine the plane has no wheels and is suspended over the treadmill, is the treadmill preventing the plane from moving forward ?

In contrast a car is completely different as the wheels are the element that makes the thing move. A toy car on a gym treadmill however can be pushed forward using the same energy no mater if the treadmill is moving or not (possibly with some additional energy needed to overcome additional friction in the wheels due to more revolutions).
 
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LOAM said:
As soon as the planes engines exert any form of thrust (no matter how small but sufficient to make it move in its usual environment) the plane will start to move regardless of what the tread mill is doing underneath it.

The wheels on a Jet aren't driven, so the treadmill can never under any circumstances cancel the thrust of the planes jets out, their rotation will simply speed up indefinitely as the plane moves forward, only slowing down as the plane takes off. This is because the thrust of the plane is not from the wheels.

A car is completely different as the wheels are the element that makes the thing move. A toy car on a gym treadmill can be pushed forward using the same energy no mater if the treadmill is moving or not.
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********. You're missing the point entirely mate. Yes, the planes wheels aren't driven. They ARE, however, the only form of contact between the plane and the treadmill. If the plane had no thrust, and the treadmill moved in any direction, the plane would go with it. That goes for any object.

If you want to keep the plane stationary, you have to provide a forward speed equal and opposite to the treadmill. This involves turning the wheels, by whatever manner necessary. You could attach a tug to the plane, and pull it forward at the equal and opposite velocity of the treadmill, and it would have the same effect - the plane stays in the same place.

We're talking about using the aircraft's engines, so if they provide the exact thrust to keep the plane moving forward at the equal and opposite volicity of the treadmill, it WILL remain stationary. The fact the the wheels aren't driven is irrelevant...
 
LOAM said:
Because the wheels don't drive the plane forward, you can remove them from the experiment, so Imagine the plane has no wheels and is suspended over the treadmill, is the treadmill preventing the plane from moving forward ?
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If it's not touching the tradmill, the whole thing becomes irrelevant...:rolleyes:
 
its the same thing, they aren't used to move the plane in the first place so you cant use an opposing force to cancel it out, because they aren't creating a force in the first place.
 
Penfold101 said:
Ok - imagine yourself on a perfectly level treadmill. You're wearing rollerskates. you turn on the treadmill. What happens...?
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I have no means of making any thrust (well I could fart) so I could potentially roll backwards, however strap me a device to provide thrust on my arms and nothing the treadmill can do can prevent me from moving forward.

Read this, but read all of it.

http://www.airplaneonatreadmill.com/

See his variations on questions;

1) An aeroplane is sitting at rest on a very powerful treadmill. You are at the controls of the treadmill, while I am at the controls of the aeroplane. On some signal, I begin to attempt to take flight in the plane, and you attempt to match my speed to try to keep me stationary. Will the plane take off?

2) An aeroplane is sitting at rest on a very powerful treadmill. You are at the controls of the treadmill, while I am at the controls of the aeroplane. On some signal, I throttle up the aeroplane and you turn on the treadmill, and we conspire by our joint effort to try to keep the plane stationary relative to the ground. Will the plane take off?

3) An aeroplane is sitting at rest on a very powerful treadmill. You are at the controls of the treadmill, while I am at the controls of the airplane. On some signal, I attempt to take flight in the plane, but you match my speed with the treadmill and keep me stationary relative to the ground. Will the plane take off?

1. Yes.
2. No.
3. Whoever asked this question is an idiot.
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the most important part of that is in small text, ill blow it up;
EDIT: Really, you should substitute the word "air" for ground in the above facts. I use "ground" throughout this post because of a consistent mistake made by "no-flys" in their assumption that the plane remains stationary. It doesn't remain stationary, relative to the ground or the air. The important point is that it moves relative to the air, not the ground, but I'm assuming throughout this post that there is no significant tailwind or headwind. I discuss the implications of this briefly in the section about wind tunnels.)
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Thus the plane is moving relative to the air not the ground as the jets are moving the air out the back of themselves and not powering the wheels over the ground *

* This would be exactly the same for me on roller skates on a treadmill (proving I had a method of propulsion that made my speed relative to air and not the ground / treadmill)
 
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Just another website by one fan of his side of the theory - means nothing mate... He's also assuming the aircraft weighs nothing and has no friction with the ground. I'm trying to be a little more realistic about things...
 
LOAM said:
however strap me a device to provide thrust on my arms and nothing the treadmill can do can prevent me from moving forward.
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Nonsense. If you could get the treadmill to go fast enough it would push you off the back. Not unless your rollerskates had frictionless wheels.
 
my thrust is relative to the air not the treadmill, the wheels on my skates would simply spin faster whilst I went forward.
 
What can I say, I got sucked in.

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Nate
 
Erm Newton will be spinning in his grave.

If the force exerted by the treadmill is equal to the force exerted by the engines there would be a net zero force and so the plane wont move, you can argue all you like how this may be impossible in our world but physics deals with "impossible" all the time.
 
think of it like this, imagine a winch located at the end of the long treadmill but not on it, the winch rope is tied to the front of the jet, the treadmill is started and the winch are started at the same speed at the same time (the treadmill can at all times match the winch speed).

What is going to happen to the rope ? the treadmill in no direct contact with the winch can't prevent it from drawing its rope in, thus its getting shorter. which in turn pulls the plane towards it.
 
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LOAM said:
think of it like this, imagine a winch located at the end of the long treadmill but not on it, the winch rope is tied to the front of the jet, the treadmill is started and the winch are started at the same speed at the same time (the treadmill can at all times match the winch speed).

What is going to happen to the rope ? the treadmill in no direct contact with the winch can't prevent it from drawing its rope in, thus its getting shorter because. which in turn is pulls the plane towards it.
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"Ladies and gentlemen, this is Chewbacca. Chewbacca is a Wookiee from the planet Kashyyyk. But Chewbacca lives on the planet Endor. Now think about it; that does not make sense!"
 
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