You have a plane and a conveyor belt.

[Kalvin00]

Originally posted by: BlinderBomber
Example. You are on a treadmill, wearing roller blades. There is rope attached to the wall. You are holding the rope. Think about what happens if you pull on the rope. You move forward. Even if the treadmill spins faster you still move forward. If if the treadmill tries to 'match your speed' or whatever, you still move forward. You can actually pull yourself off the front of the treadmill using this method. This is because the force (you pulling on the rope) has no opposite force to counter it because the wheels of your roller blades spin freely.

Essentially that is the same principle behind the plane, except in the plane's case the rope are the engines. Nomatter how fast that treadmill spins, the plane moves forward, just like you move forward on a treadmill.

A nice example to prove gilligans wrong. :thumbsup:

 

[Kalvin00]

Originally posted by: gilligans

and you think your smart? now you just changed the question. since you added another force(pulling of a rope) why dont i add another force(pulling of a rope on the tail end) you think the plane will go anywhere? dont change the question, you might as well replace airplane and instead say helicopter. yes helicopter will fly, you see. lol. or why not say that the plane is a harrier. you kids crack me up. stupid kids, go to f&*king school please.

Wow. Can you not read/apply the example to the real situation?

The rope is the equivalent to the JET ENGINE. It forces the plane forward. What don't you get about that?

 

[ElMonoDelMar]

gilligans is an e-badass and can't be proven wrong.

 

[MidNiteMysT]

Originally posted by: gilligans
and you think your smart? now you just changed the question. since you added another force(pulling of a rope) why dont i add another force(pulling of a rope on the tail end) you think the plane will go anywhere? dont change the question, you might as well replace airplane and instead say helicopter. yes helicopter will fly, you see. lol. or why not say that the plane is a harrier. you kids crack me up. stupid kids, go to f&*king school please.

damn man, stop being such a close minded idiot and telling other people to go to school and their parents are morons. it just shows how "f&*king" dumb you are if you keep having to say that. wake up and realize that this is not a car, its a plane with engines that push air to accelerate, not accelerate through the wheels.
and he was using a analogy, ever heard of it? he didnt changing the question, he is trying to dumb it down for you since you have such a problem understanding. if only you parents could see you now...
lets try and put it another way for you...
if you take a rubber band and the toy car on the treadmill and the anchor points of the rubber bands are in front of the tread mill and the treadmill is set for 2050 mph or how ever fast you want to make it, and the rubber band is stretched around the toy car which is on the treadmill, do you think the toy car would not move foward? thats the best way i can think to put it for your sorry mind. the rubber band is basically a substitute for the thrust of the engines. its completely independent of the wheels. if you still dont/cant understand, maybe YOU should go back to school. think about it a little before you dismiss it and say your "man, you people are stoopid, go back to school" kiddie crap

 

[JDrake]

Originally posted by: BlinderBomber
Example. You are on a treadmill, wearing roller blades. There is rope attached to the wall. You are holding the rope. Think about what happens if you pull on the rope. You move forward. Even if the treadmill spins faster you still move forward. If if the treadmill tries to 'match your speed' or whatever, you still move forward. You can actually pull yourself off the front of the treadmill using this method. This is because the force (you pulling on the rope) has no opposite force to counter it because the wheels of your roller blades spin freely.

Essentially that is the same principle behind the plane, except in the plane's case the rope are the engines. Nomatter how fast that treadmill spins, the plane moves forward, just like you move forward on a treadmill.

:thumbsup:

 

[Armitage]

Originally posted by: spidey07
Since when are we assuming the wheels are frictionless?

Even so. For the plane to move it breaks the conditions of the problem.

There is no way for the plane to take off. I really don't know how to put it more simply.

Shrug - it does take of. I don't know how to put it more simply.

The original problem never says the plane doesn't move. A motionless plane is not a condition of the problem It only says that the conveyor matches the speed of the plane. That doesn't mean the plane is stationary. In fact, if you ignore the OP's rewording (aka option 1) then the conveyor only moves if the plane moves forward.

 

[spidey07]

Originally posted by: Armitage

Originally posted by: spidey07
Since when are we assuming the wheels are frictionless?

Even so. For the plane to move it breaks the conditions of the problem.

There is no way for the plane to take off. I really don't know how to put it more simply.

Shrug - it does take of. I don't know how to put it more simply.

The original problem never says the plane doesn't move. A motionless plane is not a condition of the problem It only says that the conveyor matches the speed of the plane. That doesn't mean the plane is stationary. In fact, if you ignore the OP's rewording (aka option 1) then the conveyor only moves if the plane moves forward.

i understand. I am taking the question as stated, literally.

But I'm also trying to point out that said conveyor can move the plane backward as others have vehemently (sp?) said that it cannot.

the pulling rope is a decent analogy, but there is no limit on how fast I can make the conveyor go to match the speed of the rollerblade wheels. And if you do make any forward progress by pulling this rope then we are no longer talking about the original problem and are operating outside of the constraints of it.

You can directly conclude that the plane cannot move forward if the conveyor matches the speed of the wheels. It's a logic puzzle, not a physics one.

You have two possible scenarios - plane moves forward or plane does not. By logic you can eliminate the plane moving forward one.

 

[MaxFusion16]

why is this still not settled?

THE PLANE WILL TAKE OFF!!!

it doesn't matter which condition you apply here, the thrust of the plane is applied directly by air blown out of the turbines, it's not the wheels that are being powered.
So the conveyor belt can't match the speed of the wheels, it's NOT possible, hence it's not possible to match the forward motion of the plane either.
The plane will rocket forward and take off.

anyone who has taken physics should understand this, just draw a free body diagram.

first force:
the turbines move air, they push air out of the back of the plane, and according to newton, there is an equal and opposite force on the turbines. But since the turbines are fixed to the plane, now you have thrust applied to the plane.

second force:
the conveyor belt is acting on the wheels, NOT the plane, it's a seperate system. Yes, the wheels are attached to the plane, but they are wheels, they are able to rotate, the force is just wasted spinning the wheels. The plane will feel nothing except a little friction force.

 

[91TTZ]

Originally posted by: gilligans
i cant believe how stupid you guys are. there is no way the plane will take off. in order for it to fly, there must be lift on the wings. there will be no lift because the plane isnt moving.

normally, a plane takes off because the jets/propellars drive the plane foward thus getting lift on the airplane. in this situation, the jets/propellars are on but is being negated by the conveyor belt. the faster the plane tries to go forward, the faster the conveyor belt moves in the opposite directing, thus keeping the plane still.

this is the end of it.


THE PLANE WILL NOT FLY. PERIOD.

LOL

 

[Dissipate]

1 = .9999....

/thread

 

[spidey07]

Originally posted by: Dissipate
1 = .9999....

/thread

At least that can be proven.

Given the conditions of the problem here the plane cannot and will not take off.

 

[ABErickson]

Originally posted by: D1gger
The wheels are not driving the plane forward, the engines are, so the plane moves forward until the air passing over the wings gives it enough lift to take off. The wheels spinning on the conveyor belt have absolutely nothing to do with the physics of a plane flying.

FTW.

 

[conehead433]

Originally posted by: 91TTZ

Originally posted by: gilligans
i cant believe how stupid you guys are. there is no way the plane will take off. in order for it to fly, there must be lift on the wings. there will be no lift because the plane isnt moving.

normally, a plane takes off because the jets/propellars drive the plane foward thus getting lift on the airplane. in this situation, the jets/propellars are on but is being negated by the conveyor belt. the faster the plane tries to go forward, the faster the conveyor belt moves in the opposite directing, thus keeping the plane still.

this is the end of it.


THE PLANE WILL NOT FLY. PERIOD.

LOL

Being on a conveyor belt with the belt matching the plane's forward speed is the same as a plane sitting with it's props going with the wheels chocked. No air lift equals sitting stationary.

 

[BeauJangles]

Originally posted by: spidey07
Since when are we assuming the wheels are frictionless?

Even so. For the plane to move it breaks the conditions of the problem.

There is no way for the plane to take off. I really don't know how to put it more simply.

Assume 0 friction. Read my example again. It is analogous to the plane example except we have substituted jet engines for a rope. The plane does take off, just like you move forward on the treadmill.

 

[BeauJangles]

Originally posted by: gilligans

and you think your smart? now you just changed the question. since you added another force(pulling of a rope) why dont i add another force(pulling of a rope on the tail end) you think the plane will go anywhere? dont change the question, you might as well replace airplane and instead say helicopter. yes helicopter will fly, you see. lol. or why not say that the plane is a harrier. you kids crack me up. stupid kids, go to f&*king school please.

Don't swear at me. Read my example again. There is no other force added. There are the same number of forces involved in my analogy as in the plane situation. Please. Read it again, carefully.

I don't see why you need to be so arrogant and mean to me, I'm just trying to provide another way to see the problem. Next time, think before you open your mouth, and try to be respectful.

 

[Cerpin Taxt]

Originally posted by: conehead433

Being on a conveyor belt with the belt matching the plane's forward speed is the same as a plane sitting with it's props going with the wheels chocked. No air lift equals sitting stationary.

It would be great if someone would take the time to amass a list of all the people that still think the plane won't fly so that we can point and laugh at all of the idiots simultaneously. For me, it would also be helpful for future discussions if I could easily cross-check the list to determine if the person I'm discussing with at any given time is a confirmed idiot.

 

[BeauJangles]

Originally posted by: Garth

Originally posted by: conehead433

Being on a conveyor belt with the belt matching the plane's forward speed is the same as a plane sitting with it's props going with the wheels chocked. No air lift equals sitting stationary.

It would be great if someone would take the time to amass a list of all the people that still think the plane won't fly so that we can point and laugh at all of the idiots simultaneously. For me, it would also be helpful for future discussions if I could easily cross-check the list to determine if the person I'm discussing with at any given time is a confirmed idiot.

Honestly, it took me about 30 min to figure this one out. At first I was convinced it wouldn't take off, but after a little diagram and some thinking I realized I was wrong. I can see why this is a very confusing problem, so I don't think we should hold this against people. We should make a list of everyone who has been obnoxious for no reason though, that is completely uncalled for.

 

[spidey07]

Originally posted by: Garth

Originally posted by: conehead433

Being on a conveyor belt with the belt matching the plane's forward speed is the same as a plane sitting with it's props going with the wheels chocked. No air lift equals sitting stationary.

It would be great if someone would take the time to amass a list of all the people that still think the plane won't fly so that we can point and laugh at all of the idiots simultaneously. For me, it would also be helpful for future discussions if I could easily cross-check the list to determine if the person I'm discussing with at any given time is a confirmed idiot.

Present.

Count me. Although i don't think I'm an idiot (stupid at times, sure...but no idiot). Just somebody who is taking the original problem and analyzing it.

I will still standby the constraints and conditions of the problem and point out that if the plane does move forward then we are outside the bounds of the problem presented. I also agree that the question is fubarred and most likely not possible in the real world. But that is the question and conditions we have.

I am completely aware of all the forces involved and do have an idea of flight as I've flown remote controlled planes for about 20 years now. Sure I'm no pilot, but the concepts remain the same. I understand how a plane works very well and am not making an analogy to a car.

Logic FTW!

 

[PurdueRy]

I give in:

Here

This assumes negligible friction from bearings. However, I think we all can agree an engine would have no trouble overcoming such friction.

 

[BeauJangles]

Originally posted by: spidey07

Originally posted by: Garth

Originally posted by: conehead433

Being on a conveyor belt with the belt matching the plane's forward speed is the same as a plane sitting with it's props going with the wheels chocked. No air lift equals sitting stationary.

It would be great if someone would take the time to amass a list of all the people that still think the plane won't fly so that we can point and laugh at all of the idiots simultaneously. For me, it would also be helpful for future discussions if I could easily cross-check the list to determine if the person I'm discussing with at any given time is a confirmed idiot.

Present.

Count me. Although i don't think I'm an idiot (stupid at times, sure...but no idiot). Just somebody who is taking the original problem and analyzing it.

I will still standby the constraints and conditions of the problem and point out that if the plane does move forward then we are outside the bounds of the problem presented. I also agree that the question is fubarred and most likely not possible in the real world. But that is the question and conditions we have.

I am completely aware of all the forces involved and do have an idea of flight as I've flown remote controlled planes for about 20 years now. Sure I'm no pilot, but the concepts remain the same. I understand how a plane works very well and am not making an analogy to a car.

Logic FTW!

So how does the plane moving forward fall 'outside the bounds of the problem presented?' I'm not being a dick, I just haven't read the problem as originally phrased.

 

[spidey07]

Originally posted by: PurdueRy
I give in:

Here

meh, purdue couldn't teach physics if they tried.

Have you had statics/dynamics for engineers? that class was a lot of fun (and a bitch to boot)

Soaped the fountain lately?

 

[PurdueRy]

Originally posted by: spidey07

Originally posted by: PurdueRy
I give in:

Here

meh, purdue couldn't teach physics if they tried.

Have you had statics/dynamics for engineers? that class was a lot of fun (and a bitch to boot)

Soaped the fountain lately?

Not lately, its been cold(Except today )

And ya, I took statics/dynamics/mechanics

Class was not bad, just homework was tedious

 

[mchammer]

omfg what is going on in here??!!?

 

[PurdueRy]

Originally posted by: mchammer
omfg what is going on in here??!!?

I posted proof of why the rollerblade case is a very good example of this problem.

 

[mchammer]

Originally posted by: PurdueRy

Originally posted by: mchammer
omfg what is going on in here??!!?

I posted proof of why the rollerblade case is a very good example of this problem.

In general though, I thought everything was settled once Tom got convinced.