Mase
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but the plane and conveyor are not at a fixed speed. As the plane accelerates, so does the belt at the same rate, however the forces exerted by each one are not the same, which results in the plane moving forward, gaining lift and eventually taking off. The fact that the belt is accelerating at the same rate doesn't affect the plane as they are both essentially split by a bearing (the wheels), so have little or no affect on one anothers progress.
Mase
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Hammer
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svm, there is only one concievable time that the plane and the conveyor can be at the same speed to be stationary, when they are both not travelling at all.
If you are saying it stays stationary while the conveyor moves then the plane isnt moving at the same speed as the conveyor is.
i also must apologise for the feeling of 5 on 1 thats come over the thread its not my intention to be part of that, just want to put my point across 
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Paul_J
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quote:
Originally posted by SVM 286
quote:
Originally posted by Paul_J
If you're saying the plane can move forward then that completely negates this entire thread and Brad's question Paul.
no it doesn't. Brads thing doesn't say forces are equal. It says speeds are equal. Just because the belt is going 100 mph, it doesn't mean it's Holding the plane there. As its not a force against the plane. It's a force against the wheels which are turning, not pushing against the plane. They key thing is in equilibrium's is Equal forces. (not speeds)
If I have a force going this way -------> <------- it must be equal to one going the other way to be equal.
There's a force of say 26400 lb of thrust going ---------> from the plane.
What force is there acting against it?
there is a conveyer belt going <------------- the same speed, but that's not holding the plane back like a equal forced wind would - it's merely spinning the wheels which are under it. Possibly applying a slight force due to the friction within the wheel bearings.
Thus if theres 16400 force -------> <-- and only say 1000 force resistance
the forces are not equal and the plane will move down the conveyer belt until it reaches a high enough speed to take off.
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SVM 286
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quote:
Originally posted by Ian
I think the stationary thing is quite possible, I just also feel that the plane would have no problem overcoming it.
Not without lift Ian, and not if the belt can match any speed.
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Ian
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Location: Liverpool
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Jet engine moves air.
If you can push some air about you can move.
Ground speed does not matter.
Belt speed and therefore ground speed through wheels with low friction would not effect your engines ability to push air about.
You would be able to push air. You would be able to move.
If the belt and plane were travelling at the same speed, the wheels on the plane would be spinning their ass off, but the plane would still be moving and therefore lift.
The belt would offer no impedance regardless of its speed.
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SVM 286
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quote:
Originally posted by Ian
It moves in relation to the air, as the engines propel against the air.
Only when it is able to, and is making progress along the ground Ian.
If the ground won't let it, it can't can it?
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Paul_J
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SVN mate you need to learn what speed is and what a force is.
there's a big difference. Speed is a measure of how fast something moves, a Force is a FORCE acting.
If you walk towards me at 5 mph, with a force of say 100 Nm and I walk at you at 5mph with only a force of 70 Nm, will you be able to walk forward?
or will we meet in the middle and stop?
I think you'll be able to push me backwards and continue walking forward. Regardless of our speeds being the same.
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Ian
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The ground has no say in the matter as the frictionless wheels don't transmit any loss.
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Ste
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FFS the plane will take off. the wheels will free wheel on the conveyor belt and only the friction in the bearings will cause any force to move the plane backwards. as the engines accelerate the will easily ~(within 10% of the engines potential thrust) start moving the plane forwards. if you say the belts speed increases proportionately with the speed of the aircraft then the wheels will meerly spin faster but the drag coefficient of the bearings will remain constant therefore not affecting the forwards momentum of the plane. it will continue to accelerate untill it reaches the airspeed needed for that particular plane to take off (boeing 737 ~ 130-155 knots depending on weight). the only difference will be that the usual distance needed to take (1671 meters) will now be slightly further due to the drag of the wheel bearings. THE PLANE HAS NOW TAKEN OFF. PLEASE STOP ARGUING AS THIS IS THE DEFINITIVE ANSWER. AND YES I AM QUALIFIED TO ANSWER THIS QUESTION.
I would rather lose by a mile because i built my own car, than win by an inch because someone else built it for me.
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Steve
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believe me, live lee will argue mate
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SVM 286
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quote:
Originally posted by Paul_J
^ Sigh ^ - I suggest reading Ian, or Steve's, or Jules or whomever's posts.
Paul, none of us have carried this experiment out yet we all have at least a rudimentary grasp of physics.
I'd love to know what qualifies you to talk to me like i'm a moron when we are essentially peers on this forum.
And i'd like to know what makes you so utterly convinced that you are right and I am wrong and ridicule worthy.
I regret ever opening this thread to read it. I regret responding to it and would not be surprised if Ian trashed it.
It has become a farce.
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Robin
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and SVM 
edit: he will argue 
[Edited on 24-05-2006 by robmarriott]
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SVM 286
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quote:
Originally posted by robmarriott
OMFG *shakes head in disbelief*
About what Robin?
The whole point is that the plane wouldn't be able to move.
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SVM 286
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quote:
Originally posted by Jamescorsa97
SVM are u stringing us all along into one big joke that you don't actually understand this?
No James, are you?
I cannot believe that I am on my own on this one.
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Robin
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the fact that we were all arguing that it would happen if the plane could move, and thinking that you were disagreeing, then you agreed, and i was surprised
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Ian
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quote:
Originally posted by SVM 286
The whole point is that the plane wouldn't be able to move.
What is stopping it out of interest?
Loads of jet thrust in its favour - and what drag?
[Edited on 24-05-2006 by Ian]
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Paul_J
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I don't really know why your aiming your responsese directly at me, I'm just getting a bit fed up as I'm supposed to be revising for an exam tommorrow - but instead I've been on here just repeating the same thing out of frustration as I don't like to be wrong.
The problem is SVN, your grasp of physics doesn't seem to be correct. That's not an insult, but the fact you seem to be having problems determining the difference between a FORCE and a measurement of SPEED.
I don't think you are a moron, or a idiot. I just think you should believe us, and get someone to explain it to you. Rather than thinking we're the ones who are in the wrong because we've merely missed something simple.
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SVM 286
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quote:
Originally posted by mase5
but the plane and conveyor are not at a fixed speed. As the plane accelerates, so does the belt at the same rate, however the forces exerted by each one are not the same, which results in the plane moving forward,
Not according to Brad's statement Mase. He simply put that both travel at the same speed.
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John
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lmao paul i've been doing the same.
I read this, went to an exam, came back and have been devoting most of my time to it since, and i'm supposed to be studying for an exam tomorrow.
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Steve
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SVM believe me, when it clicks, you will know why people like me know 100% we are right
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Hammer
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quote:
Originally posted by SVM 286
quote:
Originally posted by mase5
but the plane and conveyor are not at a fixed speed. As the plane accelerates, so does the belt at the same rate, however the forces exerted by each one are not the same, which results in the plane moving forward,
Not according to Brad's statement Mase. He simply put that both travel at the same speed.
how can a plane move at speed and be stationary though 
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Paul_J
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quote:
Originally posted by SVM 286
The whole point is that the plane wouldn't be able to move.
The whole point isn't that the plane wouldn't be able to move. The question is effectively will the plane be able to move.
As we all no without movement = no lift.
So the question is Will the plane be able to move to get lift.
The answer is yes.
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Robin
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i have to say, this has made me post/view for the past few hours
i hate you bradley
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SVM 286
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Location: pain
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quote:
Originally posted by Sxi04
If you are saying it stays stationary while the conveyor moves then the plane isnt moving at the same speed as the conveyor is.
No Mr 04, geographically stationary, i.e. stationary in realtion to it's surroundings, due to the belt counteracting it's progress.
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Joe
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Registered: 20th Jun 04
Location: Hesketh Bank, Lancashire
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quote:
Originally posted by Paul_J
no it doesn't. Brads thing doesn't say forces are equal. It says speeds are equal. Just because the belt is going 100 mph, it doesn't mean it's Holding the plane there. As its not a force against the plane. It's a force against the wheels which are turning, not pushing against the plane. They key thing is in equilibrium's is Equal forces. (not speeds)
If I have a force going this way -------> <------- it must be equal to one going the other way to be equal.
There's a force of say 26400 lb of thrust going ---------> from the plane.
What force is there acting against it?
there is a conveyer belt going <------------- the same speed, but that's not holding the plane back like a equal forced wind would - it's merely spinning the wheels which are under it. Possibly applying a slight force due to the friction within the wheel bearings.
Thus if theres 16400 force -------> <-- and only say 1000 force resistance
the forces are not equal and the plane will move down the conveyer belt until it reaches a high enough speed to take off.
This sums it up best to me, I have'nt read all the pages of this as i cant be arsed. And i originally thought that it would'nt take off. Reading this I realise it could.
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