Mythbusters punk'd whole internet

[randay]

Originally posted by: Fenixgoon
i would make a response to the above assertion, but i simply can't. i just can't. i need to let this thread die. i srsly do

edit: by above assertion i mean astroidea's post

The thread starter doesnt state the limit of this threads life so the only reasonable assumption is that its infinite.

 

[Kev]

Originally posted by: spidey07

Originally posted by: Kev

Originally posted by: spidey07
And you are still breaking the original constraints of the question. I don't see why this is so hard for people to get.

Any advancement by the plane will be met with acceleration of the treadmill preventing the plane from moving. The force of the engines if finite. By very definition of the problem the treadmills force (acceleration) isn't.

Going by laws of physics of the universe we currently live in, the italicized statement above is *physically impossible*

Come back once you comprehend that, mkay?

I understand it fully. Hence the paradox.

Come back when you stay within bounds of the problem. As soon as the plane advances a single micron, that wheels are moving forward faster than the treadmill, which according to the problem can't happen. That's where the infinite acceleration comes in.

You're not even answering the right question. What's the point of trying to answer a physics question that by definition goes against the laws of physics? It's not a paradox, you're just misinterpreting it.

 

[Kev]

Originally posted by: uclaLabrat

Originally posted by: astroidea
The plane takes of depending on which plane it is!

So the main argument that the plane would still take off is that there's no counter force keeping the plane from moving forward as the thrust of the plane is independent from the wheels. So as long as the wheels roll freely, the plane will still take off.

However, there is a counter force! Rotational friction. There is a frictional force in the bearings of the wheels. It does not roll completely freely without any opposing forces. The thrust force the plane puts out would be needed to counteract this frictional force.
Therefore, the quicker the wheels spin, the more force the plane would have to put out to spin the wheels.
But isn't the conveyer belt pushing the same amount of force on the wheels in the opposite direction?
So when would the plane actually move forward relative to the air?
Well first, let's imagine this situation:
The plane is on a conveyer belt that's moving backwards at 100mph. The plane is moving forwards at 100mph also. So right now, the plane isn't moving relative to the air right? But what would happen if the plane suddenly stopped all its engines? The coveyer belt would begin to move the plane backwards. It would no longer be able to maintain the static air speed.
Therefore, we can reasonably deduce that it does indeed take some force from the plane's thrust in order to counteract the motion of the conveyer belt.
So how much force would it take to keep the plane stationary with the air when the belt is moving backwards at 1000000000000 miles per hour? Would the plane have enough power to keep it stationary? Probably not.
But then again, is it even possible for the tires to still be in contact with the treadmill at 100000000000 miles per hour? According to newtonian physics, once the frictional force of the bearings exceed the frictional force between the tires and the surface of the conveyer belt, wouldn't the tires lose grip with the surface? Once the tires lose surface, the plane will only have to generate enough thrust to counteract the frictional force between the tires and the surface of the belt in order to move forward.

So therefore, the plane will move forward, but only when the plane is able to generate enough thrust for the friction of the tires to break free from the belt.

But is there any plane that has a powerful enough engine that can generate enough force to break free?

Let's look at the Boeing 777.
According to wikipedia, it generates 418,000N of thrust, and has a mass of 139,225kg.
The coefficient of static friction between tires and tarmac is about 0.7.
If you work out the math, µmg is (0.7)(139225)(9.8) = 956,058N.
This is over twice as much force as what the 418,000N of thrust the engines put out.
And if you consider the hundreds of opposing forces that I haven't accounted for, it's even less likely to be able to break free from the friction.
Thus, Plane DOESN'T TAKE OFF

But what if you had a plane with a better weight to thrust ratio?
Well, I let's look at the F22 Raptor.
According to wikipedia, the two turbofan engines generates a total of 311,000N of thrust. The plane when empty has a mass of 14,365kg.
So given that, let's work out the math again. (0.7)(14365)(9.8) = 98,544N
In this case, the 311,000N of thrust is significantly greater than 98,544N of frictional force. So in this case, the plane would take off!

In conclusion: THE PLANE MAY OR MAY NOT TAKE OFF DEPENDING ON WHICH PLANE IT IS!

OMG. Someone else understands friction and thrust!

How reassuring. Nice work on the analysis btw. Most coherent and lucid I've seen thus far.

And yet he's still wrong.

 

[Tweak155]

The problem that we are going to come across is that when this plane takes off during the experiment (assuming there will still be one), the nay sayers (the ones that say it won't take off), will just say it didn't match the outline of the question, specifically the one they are so adamantly talking about. So even after this plane takes off, they are still going to deny it so we are just wasting our time.

If this plane does not take off (assuming no accidents happen), then I can admit I'm wrong. I think provided some capacity that man doesn't have currently, there could be a setup where it could hold the plane still. But any decently designed airplane will take off given it has no other intentionally added burdens (more tail weight, etc). Someone go ahead and quote this if you feel the need.

 

[jagec]

Originally posted by: Kev

Originally posted by: spidey07
And you are still breaking the original constraints of the question. I don't see why this is so hard for people to get.

Any advancement by the plane will be met with acceleration of the treadmill preventing the plane from moving. The force of the engines if finite. By very definition of the problem the treadmills force (acceleration) isn't.

Going by laws of physics of the universe we currently live in, the italicized statement above is *physically impossible*

Come back once you comprehend that, mkay?

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. If you can't be bothered to read the thread before immediately posting your thoughts based on the top-of-your-head intuitive grasp of the problem which you have acquired, you shouldn't try to be so condescending to those who may have actually thought the problem through a bit further.

 

[Kev]

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

 

[Kev]

eh nevermind

 

[SlitheryDee]

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

Waitasec, the version of the problem that you two are arguing about is the one where the plane doesn't take off.

If the treadmill instantly matches the speed of the wheel then when the wheel starts turning forward at 1 RPM then the treadmill will match that speed in the opposite direction. The wheel, meanwhile, is still turning at 1 RPM. When the treadmill matches the speed of the wheel it will ADD 1 rpm to the speed of the wheel because it is in contact with the wheel. Then the wheel is moving at 2 RPM which the treadmill once again matches and adds to the speed of the wheel. Repeat ad infinitum.

What this means is that the speed of the wheel and the treadmill and the backwards force generated by the friction between the wheel and the rest of the landing gear will instantly rise to infinity. Either the landing gear of the airplane will be destroyed or, in the case of indestructible landing gear, the infinite backwards force generated by the friction between the wheels and their mounts will keep the plane virtually motionless.

If you have no (not a little, ZERO) friction between the wheels and the rest of the landing gear then the plane takes off even in this scenario.

 

[randay]

Originally posted by: SlitheryDee

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

Waitasec, the version of the problem that you two are arguing about is the one where the plane doesn't take off.

If the treadmill instantly matches the speed of the wheel then when the wheel starts turning forward at 1 RPM then the treadmill will match that speed in the opposite direction. The wheel, meanwhile, is still turning at 1 RPM. When the treadmill matches the speed of the wheel it will ADD 1 rpm to the speed of the wheel because it is in contact with the wheel. Then the wheel is moving at 2 RPM which the treadmill once again matches and adds to the speed of the wheel. Repeat ad infinitum.

What this means is that the speed of the wheel and the treadmill and the backwards force generated by the friction between the wheel and the rest of the landing gear will instantly rise to infinity. Either the landing gear of the airplane will be destroyed or, in the case of indestructible landing gear, the infinite backwards force generated by the friction between the wheels and their mounts will keep the plane virtually motionless.

If you have no (not a little, ZERO) friction between the wheels and the rest of the landing gear then the plane takes off even in this scenario.

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

 

[jjzelinski]

Originally posted by: randay

Originally posted by: SlitheryDee

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

Waitasec, the version of the problem that you two are arguing about is the one where the plane doesn't take off.

If the treadmill instantly matches the speed of the wheel then when the wheel starts turning forward at 1 RPM then the treadmill will match that speed in the opposite direction. The wheel, meanwhile, is still turning at 1 RPM. When the treadmill matches the speed of the wheel it will ADD 1 rpm to the speed of the wheel because it is in contact with the wheel. Then the wheel is moving at 2 RPM which the treadmill once again matches and adds to the speed of the wheel. Repeat ad infinitum.

What this means is that the speed of the wheel and the treadmill and the backwards force generated by the friction between the wheel and the rest of the landing gear will instantly rise to infinity. Either the landing gear of the airplane will be destroyed or, in the case of indestructible landing gear, the infinite backwards force generated by the friction between the wheels and their mounts will keep the plane virtually motionless.

If you have no (not a little, ZERO) friction between the wheels and the rest of the landing gear then the plane takes off even in this scenario.

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

I doubt the plane is going to do much more than tip over going backwards.

 

[SlitheryDee]

Originally posted by: randay

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

Huh, you're right. I didn't follow the thought through completely, but it seems the once the wheels move even one tiny bit they would continue to accelerate simply because of the constantly increasing force the treadmill must apply to them. I don't know about taking off backwards, but it seems the plane would at least move backwards at infinite speed. Huh.

Well it is what it is I guess. Still doesn't really equal a takeoff though.

 

[yhelothar]

Originally posted by: Throckmorton

Originally posted by: astroidea
The plane takes of depending on which plane it is!

So the main argument that the plane would still take off is that there's no counter force keeping the plane from moving forward as the thrust of the plane is independent from the wheels. So as long as the wheels roll freely, the plane will still take off.

However, there is a counter force! Rotational friction. There is a frictional force in the bearings of the wheels. It does not roll completely freely without any opposing forces. The thrust force the plane puts out would be needed to counteract this frictional force.
Therefore, the quicker the wheels spin, the more force the plane would have to put out to spin the wheels.
But isn't the conveyer belt pushing the same amount of force on the wheels in the opposite direction?
So when would the plane actually move forward relative to the air?
Well first, let's imagine this situation:
The plane is on a conveyer belt that's moving backwards at 100mph. The plane is moving forwards at 100mph also. So right now, the plane isn't moving relative to the air right? But what would happen if the plane suddenly stopped all its engines? The coveyer belt would begin to move the plane backwards. It would no longer be able to maintain the static air speed.
Therefore, we can reasonably deduce that it does indeed take some force from the plane's thrust in order to counteract the motion of the conveyer belt.
So how much force would it take to keep the plane stationary with the air when the belt is moving backwards at 1000000000000 miles per hour? Would the plane have enough power to keep it stationary? Probably not.
But then again, is it even possible for the tires to still be in contact with the treadmill at 100000000000 miles per hour? According to newtonian physics, once the frictional force of the bearings exceed the frictional force between the tires and the surface of the conveyer belt, wouldn't the tires lose grip with the surface? Once the tires lose surface, the plane will only have to generate enough thrust to counteract the frictional force between the tires and the surface of the belt in order to move forward.

So therefore, the plane will move forward, but only when the plane is able to generate enough thrust for the friction of the tires to break free from the belt.

But is there any plane that has a powerful enough engine that can generate enough force to break free?

Let's look at the Boeing 777.
According to wikipedia, it generates 418,000N of thrust, and has a mass of 139,225kg.
The coefficient of static friction between tires and tarmac is about 0.7.
If you work out the math, µmg is (0.7)(139225)(9.8) = 956,058N.
This is over twice as much force as what the 418,000N of thrust the engines put out.
And if you consider the hundreds of opposing forces that I haven't accounted for, it's even less likely to be able to break free from the friction.
Thus, Plane DOESN'T TAKE OFF

But what if you had a plane with a better weight to thrust ratio?
Well, I let's look at the F22 Raptor.
According to wikipedia, the two turbofan engines generates a total of 311,000N of thrust. The plane when empty has a mass of 14,365kg.
So given that, let's work out the math again. (0.7)(14365)(9.8) = 98,544N
In this case, the 311,000N of thrust is significantly greater than 98,544N of frictional force. So in this case, the plane would take off!

In conclusion: THE PLANE MAY OR MAY NOT TAKE OFF DEPENDING ON WHICH PLANE IT IS!

Edit: Nevermind. I didn't read your whole post. I don't see why you're assuming that the belt spins at such ludicrous speed. The problem states that the belt moves backward at the same speed that the plane is moving forward.

You're taking my example out of context. It's an arbitrarily large number I chosen to help imagine the factors that would take place. It's a very common tactic used in physics and science to aid in problem solving.

 

[randay]

Originally posted by: jjzelinski

Originally posted by: randay

Originally posted by: SlitheryDee

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

Waitasec, the version of the problem that you two are arguing about is the one where the plane doesn't take off.

If the treadmill instantly matches the speed of the wheel then when the wheel starts turning forward at 1 RPM then the treadmill will match that speed in the opposite direction. The wheel, meanwhile, is still turning at 1 RPM. When the treadmill matches the speed of the wheel it will ADD 1 rpm to the speed of the wheel because it is in contact with the wheel. Then the wheel is moving at 2 RPM which the treadmill once again matches and adds to the speed of the wheel. Repeat ad infinitum.

What this means is that the speed of the wheel and the treadmill and the backwards force generated by the friction between the wheel and the rest of the landing gear will instantly rise to infinity. Either the landing gear of the airplane will be destroyed or, in the case of indestructible landing gear, the infinite backwards force generated by the friction between the wheels and their mounts will keep the plane virtually motionless.

If you have no (not a little, ZERO) friction between the wheels and the rest of the landing gear then the plane takes off even in this scenario.

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

I doubt the plane is going to do much more than tip over going backwards.

i hereby designate the next 40 pages of this thread to the great debate on defining "flight".

 

[randay]

Originally posted by: SlitheryDee

Originally posted by: randay

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

Huh, you're right. I didn't follow the thought through completely, but it seems the once the wheels move even one tiny bit they would continue to accelerate simply because of the constantly increasing force the treadmill must apply to them. I don't know about taking off backwards, but it seems the plane would at least move backwards at infinite speed. Huh.

Well it is what it is I guess. Still doesn't really equal a takeoff though.

:thumbsup: of course this is all with the hypothetical and crazy unrealistic interpretation of the question. but if I can somehow convince jagec on that it would make my entire time in this thread worthwhile.

 

[jjzelinski]

Originally posted by: randay

Originally posted by: jjzelinski

Originally posted by: randay

Originally posted by: SlitheryDee

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

Waitasec, the version of the problem that you two are arguing about is the one where the plane doesn't take off.

If the treadmill instantly matches the speed of the wheel then when the wheel starts turning forward at 1 RPM then the treadmill will match that speed in the opposite direction. The wheel, meanwhile, is still turning at 1 RPM. When the treadmill matches the speed of the wheel it will ADD 1 rpm to the speed of the wheel because it is in contact with the wheel. Then the wheel is moving at 2 RPM which the treadmill once again matches and adds to the speed of the wheel. Repeat ad infinitum.

What this means is that the speed of the wheel and the treadmill and the backwards force generated by the friction between the wheel and the rest of the landing gear will instantly rise to infinity. Either the landing gear of the airplane will be destroyed or, in the case of indestructible landing gear, the infinite backwards force generated by the friction between the wheels and their mounts will keep the plane virtually motionless.

If you have no (not a little, ZERO) friction between the wheels and the rest of the landing gear then the plane takes off even in this scenario.

i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

I doubt the plane is going to do much more than tip over going backwards.

i hereby designate the next 40 pages of this thread to the great debate on defining "flight".

I tend to have a pretty specific definition for flight any time I strap myself into 747

 

[spidey07]

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

And here lies the disconnect.

You believe the plane can overcome the forces of the treadmill. This is fail at physics.

According to the problem there is no way the plane can move.

 

[jjzelinski]

Originally posted by: spidey07

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

And here lies the disconnect.

You believe the plane can overcome the forces of the treadmill. This is fail at physics.

According to the problem there is no way the plane can move.

Yeah but the debate has drifted from "I wonder if the plane will take off on the mythbusters show" to "treadmill of infinite velocity." Unless the mythbusters are way more uber then I had previously guessed then I'd say the plane will take off.

 

[Squisher]

Originally posted by: spidey07

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

And here lies the disconnect.

You believe the plane can overcome the forces of the treadmill. This is fail at physics.

According to the problem there is no way the plane can move.

If you can have a treadmill that has an infinite speed then I want frictionless bearings and tires that have an infinite speed rating.

 

[yhelothar]

Originally posted by: Kev

Originally posted by: uclaLabrat

Originally posted by: astroidea
The plane takes of depending on which plane it is!

So the main argument that the plane would still take off is that there's no counter force keeping the plane from moving forward as the thrust of the plane is independent from the wheels. So as long as the wheels roll freely, the plane will still take off.

However, there is a counter force! Rotational friction. There is a frictional force in the bearings of the wheels. It does not roll completely freely without any opposing forces. The thrust force the plane puts out would be needed to counteract this frictional force.
Therefore, the quicker the wheels spin, the more force the plane would have to put out to spin the wheels.
But isn't the conveyer belt pushing the same amount of force on the wheels in the opposite direction?
So when would the plane actually move forward relative to the air?
Well first, let's imagine this situation:
The plane is on a conveyer belt that's moving backwards at 100mph. The plane is moving forwards at 100mph also. So right now, the plane isn't moving relative to the air right? But what would happen if the plane suddenly stopped all its engines? The coveyer belt would begin to move the plane backwards. It would no longer be able to maintain the static air speed.
Therefore, we can reasonably deduce that it does indeed take some force from the plane's thrust in order to counteract the motion of the conveyer belt.
So how much force would it take to keep the plane stationary with the air when the belt is moving backwards at 1000000000000 miles per hour? Would the plane have enough power to keep it stationary? Probably not.
But then again, is it even possible for the tires to still be in contact with the treadmill at 100000000000 miles per hour? According to newtonian physics, once the frictional force of the bearings exceed the frictional force between the tires and the surface of the conveyer belt, wouldn't the tires lose grip with the surface? Once the tires lose surface, the plane will only have to generate enough thrust to counteract the frictional force between the tires and the surface of the belt in order to move forward.

So therefore, the plane will move forward, but only when the plane is able to generate enough thrust for the friction of the tires to break free from the belt.

But is there any plane that has a powerful enough engine that can generate enough force to break free?

Let's look at the Boeing 777.
According to wikipedia, it generates 418,000N of thrust, and has a mass of 139,225kg.
The coefficient of static friction between tires and tarmac is about 0.7.
If you work out the math, µmg is (0.7)(139225)(9.8) = 956,058N.
This is over twice as much force as what the 418,000N of thrust the engines put out.
And if you consider the hundreds of opposing forces that I haven't accounted for, it's even less likely to be able to break free from the friction.
Thus, Plane DOESN'T TAKE OFF

But what if you had a plane with a better weight to thrust ratio?
Well, I let's look at the F22 Raptor.
According to wikipedia, the two turbofan engines generates a total of 311,000N of thrust. The plane when empty has a mass of 14,365kg.
So given that, let's work out the math again. (0.7)(14365)(9.8) = 98,544N
In this case, the 311,000N of thrust is significantly greater than 98,544N of frictional force. So in this case, the plane would take off!

In conclusion: THE PLANE MAY OR MAY NOT TAKE OFF DEPENDING ON WHICH PLANE IT IS!

OMG. Someone else understands friction and thrust!

How reassuring. Nice work on the analysis btw. Most coherent and lucid I've seen thus far.

And yet he's still wrong.

Oh really. Well why don't you enlighten us in how the argument is flawed.
:roll:

 

[Kev]

Originally posted by: jjzelinski

Originally posted by: spidey07

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

And here lies the disconnect.

You believe the plane can overcome the forces of the treadmill. This is fail at physics.

According to the problem there is no way the plane can move.

Yeah but the debate has drifted from "I wonder if the plane will take off on the mythbusters show" to "treadmill of infinite velocity." Unless the mythbusters are way more uber then I had previously guessed then I'd say the plane will take off.

The plane will still take off on a treadmill of infinite velocity. THERE IS NO FORCE OPPOSING THE FUSELAGE, JUST THE WHEELS.

 

[her209]

Originally posted by: randay
i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

See my post about maximum frictional force applied and wheel slippage.

 

[jjzelinski]

Originally posted by: Kev

Originally posted by: jjzelinski

Originally posted by: spidey07

Originally posted by: Kev

That's not true. Acceleration of the treadmill creates an opposing force to the plane's engines. This has been explained, calculated, and diagrammed umpteen times in this thread. I

It's not even possible for the treadmill to create an "opposing force to the plane's engines." All the explanations, calculations, and diagrams that "support" this are flat out wrong. The only force that the treadmill creates is on the wheels of the plane. As soon as the plane begins to generate thrust, it will move forward no matter how fast the treadmill and wheels spin, because there is no force opposing the body of the plane. The plane's speed is not dependent on the speed of the wheels. The wheels are simply there to create a low friction surface for the plane to accelerate over.

And here lies the disconnect.

You believe the plane can overcome the forces of the treadmill. This is fail at physics.

According to the problem there is no way the plane can move.

Yeah but the debate has drifted from "I wonder if the plane will take off on the mythbusters show" to "treadmill of infinite velocity." Unless the mythbusters are way more uber then I had previously guessed then I'd say the plane will take off.

The plane will still take off on a treadmill of infinite velocity. THERE IS NO FORCE OPPOSING THE FUSELAGE, JUST THE WHEELS.

Well now you got me confused there sir. Did we establish at some point that any plane can take off with wheels that are essentially locked up due to friction? That's assuming they don't incinerate, which they probably would. That being said, once the wheels aren't free spinning they WOULD be imparting force from the treadmill onto the fuselage... right? Maybe?

 

[randay]

Originally posted by: her209

Originally posted by: randay
i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

See my post about maximum frictional force applied and wheel slippage.

i understand that fact and agree, most people are ignoring friction though.

 

[Alistar7]

Originally posted by: randay

Originally posted by: her209

Originally posted by: randay
i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

See my post about maximum frictional force applied and wheel slippage.

i understand that fact and agree, most people are ignoring friction though.

And assuming the plane is not capable of vectored thrust.

 

[jagec]

Originally posted by: randay

Originally posted by: her209

Originally posted by: randay
i dont understand how, if the treadmill accelerates infinitely, the airplane is supposed to be held in place. it should start moving backwards as the opposing force increases infinitely. in which case the airplane takes off backwards. if somehow the airplane is to be held in place then the acceleration and speed of the treadmill is finite.

See my post about maximum frictional force applied and wheel slippage.

i understand that fact and agree, most people are ignoring friction though.

And wheel mass.