Long rod question
- Thread starter moon man
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Think of it like this, its not the forced required to push it forward, its the forced require for the plane to spin against its own wheels. This can be assumed by the friction applied by its weight, gravity to the bearings transfered onto the belt.
I understand your analogy, but for the sake of this experiment, it might try and make it clearer but its wrong.
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Friction may be influenced by gravity, but since when is it dependant on it?
Are you trying to say that in deep space everything suddenly becomes slippery? lol
I'm just nit-picking now
no probably justs didnt explain myself enough, i just meant the plane would have to weightless for the wheels to have no friction against the belt. or fixed from above
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There is no 'Force pushing', or 'against it's own wheels'
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Ah, but there's the interesting thing! Where is the friction and what does it do?
It is the friction between the wheels and their axles that opposes the motion, not between the wheels and the ground. So no matter how light the plane, as long as the wheels are turning there would still be friction.
yes thats exactly what i was getting at, it is the axles that opposes the motion, any thrust necessary forwards would only be to counter that and allow the wheels to start spinning freely under the plane. Stop that thrust and it continues to motion backwards.
Yeah, but what's your point? The amount of thrust needed to counter the friction between the bearings and the wheel would be tiny. It'd move backwards until the brakes were turned off, and a tiny amount of thrust would overcome the friction and send it on its merry way.
A very large treadmill placed upright in front of the plane, like a wall. That could do it.
The problem with the aeroplane question is that in most cases it is badly or incorrectly worded, therefore allowing people to come to seemingly correct answers.
A plane cannot fly without airspeed, it doesnt matter where the airspeed comes from, whether its a high wind or the plane being pushed or pulled through the air (Propeller powered planes dont fly because the prop pushes air over the wings which ever loon said that in this thread).
Thats all that matters in the question, not friction, not wheel bearings, air MUST travel over the wings to generate lift, thats all people need to worry about.
(N.B we are not talking about rockets either, with no wings, that isnt the question)
A plane cannot fly without airspeed, it doesnt matter where the airspeed comes from, whether its a high wind or the plane being pushed or pulled through the air (Propeller powered planes dont fly because the prop pushes air over the wings which ever loon said that in this thread).
Thats all that matters in the question, not friction, not wheel bearings, air MUST travel over the wings to generate lift, thats all people need to worry about.
(N.B we are not talking about rockets either, with no wings, that isnt the question)
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Caporegime
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/unsubscribes
Ignore the wheels, conveyers, bearings, spinning twice as fast whatever.
They are not important.
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Soldato
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Still doesn't stop the plane taking off if its on a treadmill. You were suggesting that it would fail to take off if it had a jet engine.
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