Ok so your saying that if i have a plane with a wheel speed of 2 m/s and it is on a treadmill going at 3 m/s the plane will not have a net speed of -1 m/s. What elementary school did you fail math at.
Originally posted by: PurdueRy
Originally posted by: smack Down
Originally posted by: PurdueRy
Originally posted by: smack Down
I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.
Ok doing good.
But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.
And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.
However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.
So where is the energy going in your theory? It can't just dissipate?
I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.
Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.
Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?
IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.
Because it is wrong.
Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.
Sure.
Lets look at the wheels on the car. You say they are attached to the drive train right? the drive train is the transmission and engine. So when a the wheels on a car spin it turns the transimission which in turn turns the engine force the pistons up and down. Which part of that system makes it so the wheels can't spin?
The engine applies force via the wheels which must turn to propel the car forward. A Plane does not. That is all you need to know. If the treadmill is moving at 3m/s then the wheels must propel the car faster than 3m/s just to start providing any forward acceleration. This is vastly different than the plane scenario.
For a plane to keep up with a treadmill it doesn't need to travel at the same speed because it just has to counter the very small friction forces. For a car, it must travel at the exact same speed because that is where its force is being applied to.
As I said before, if you can't grasp my first example, you and your physics are a lost cause.
Originally posted by: smack Down
Originally posted by: PurdueRy
Originally posted by: smack Down
Originally posted by: PurdueRy
Originally posted by: smack Down
I've read through your post in which I think you are trying show that if the plane does indeed move forward and the car remains stationary despite putting out the same amount of power (i.e. transferring same amount of energy) then the car somehow has less kinetic energy than the plane.
Ok doing good.
But this is obviously not a problem. It is circular logic. Saying the plane has some kinetic energy and the car does not (except moving parts in car and wheels) is no different to simply stating the plane will move forward and the car will not.
And here is where you make the mistake. It isn't a circular logic it is called a proof by contradiction. Either the theory of conservation of energy is wrong or that the plane behavies differently then the car is wrong because as you remember both had the same starting energy.
However the car cannot transfer its engine's energy to the treadmill as the treadmill moves away as quickly as the wheels turn effectively providing no friction in order to create a net force on the body of the car.
So where is the energy going in your theory? It can't just dissipate?
I'm sure you'd agree treadmill spinning beneath a car's wheels at the right speed is no different to a car being suspended in mid-air.
Sorry that isn't really true. It would only be true if the car was in a vacuum and there was no friction and engine was producing zero thrust. If the engine was producing power you would have to keep accelerating the treadmill to keep the car in place.
Not enough friction to move forwards. However surely you can see that a plane suspended in mid-air could move forwards?
IN ANY CASE this is quite an odd way to explain it, I don't understand how you don't appreciate the explanation which usually make most people say "oh yeah I see, I get it now" as PurdueRy did above.
Because it is wrong.
Hahaha. That's a good one. As you seem so fond of, point out the flaws so we can try to grasp where your logic is failing you. You like physics so you should be able to draw the FBD. That should explain everything to you. If you can't draw it, then don't bother posting more until you figure out how.
Sure.
Lets look at the wheels on the car. You say they are attached to the drive train right? the drive train is the transmission and engine. So when a the wheels on a car spin it turns the transimission which in turn turns the engine force the pistons up and down. Which part of that system makes it so the wheels can't spin?
The engine applies force via the wheels which must turn to propel the car forward. A Plane does not. That is all you need to know. If the treadmill is moving at 3m/s then the wheels must propel the car faster than 3m/s just to start providing any forward acceleration. This is vastly different than the plane scenario.
For a plane to keep up with a treadmill it doesn't need to travel at the same speed because it just has to counter the very small friction forces. For a car, it must travel at the exact same speed because that is where its force is being applied to.
As I said before, if you can't grasp my first example, you and your physics are a lost cause.
Ok so your saying that if i have a plane with a wheel speed of 2 m/s and it is on a treadmill going at 3 m/s the plane will not have a net speed of -1 m/s. What elementary school did you fail math at.
Originally posted by: rikadik
Originally posted by: smack Down
So where is the energy going in your theory? It can't just dissipate?
The energy is making the wheels spin. That's where the energy is going. It's really not difficult to understand. But the wheels cannot use their energy to create a forward force on the car as there is essentially no friction with the treadmill! There is no lost energy - the car's kinetic energy is just in the wheels spinning faster and faster.
A plane however converts most of its energy into air rushing out of the engines causing a forward force on the plane.
But if you're such a physics genius (and not just a trolling retard like most suggest) then why don't YOU explain where the energy produced by the engines is going in the plane situation if you claim it sits still?
Originally posted by: smack Down
Originally posted by: rikadik
Originally posted by: smack Down
So where is the energy going in your theory? It can't just dissipate?
The energy is making the wheels spin. That's where the energy is going. It's really not difficult to understand. But the wheels cannot use their energy to create a forward force on the car as there is essentially no friction with the treadmill! There is no lost energy - the car's kinetic energy is just in the wheels spinning faster and faster.
A plane however converts most of its energy into air rushing out of the engines causing a forward force on the plane.
But if you're such a physics genius (and not just a trolling retard like most suggest) then why don't YOU explain where the energy produced by the engines is going in the plane situation if you claim it sits still?
What the hell do you mean there is no friction? There is infinite friction the tires do not slip.
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
Ah yes, I remember your lack of comprehension on this subject in a couple of the long previous threads. I see you still don't understand simple physics. Well done.Originally posted by: NanoStuff
The plane will fly only as a result of the deadlock of the question. The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
In the real world there's also a latency between the plane's forward acceleration and the belt's compensation, giving the plane some theoretical escape route.
It makes no difference whether it's a car or plane on the belt in regards to it's ability to move forward for reasons that you're not about to understand now if you don't already.
A belt can and does prevent absolute forward movement without much difficulty by compensating for wheel rotation, this is regularly used in vehicle testing. The belt could very easily prevent the plane from moving had the question not implicitly required the plane to move. Those that say the plane will take off (which is what will happen presuming they do the test correctly, don't count on it), are greatly underestimating just how easily it could have not taken off.
Originally posted by: smack Down
Originally posted by: sdifox
Originally posted by: smack Down
Originally posted by: DanTMWTMP
I've never seen a more dense person who refuses to thoroughly read anything than Jandrews.
The argument isn't about wind going over the wings. It's about the plane moving foward in relation to a point outside of the threadmill/plane model. In relation to this point, the plane moves forward as if the treadmill is nonexistent. Numerous youtube videos already show that the plane moves foward. Engines act on the air, not on the ground.
A Car WILL stay stationary
A plane will not.
I have no idea why you are so stupidly dense not to realize this utterly simple riddle.
You are completely wrong. A Car and plane will behave identical on a treadmill.
AS for the physics lets pretend that we have two cars that have the same mass(m), same moment of inertia(i), and no friction. For the sake of simplicity lets take the acceleration at 1 m/s/s
On a road do you agree that they would reach a speed of 1 m/s after one second of driving? and both have the same amount of kinetic energy? 1 * m + 1 * i
Ok now lets put our two cars on the same treadmill. Your theory is the the rocket car will still accelerate at 1 m/s/s (or some other value greater then zero) and the engine car will accelerate at 0 m/s/s (that is stay in place). Correct? Additional you claim that the treadmill will be going backwards at a minimum of 1 m/s/s (In reality it would be going faster then this. The speed depends on the mass of the car. 1 m/s/s is only true with a car of zero mass.)
The rocket car energy is 1 * m + i * (1 + Vtreadmill)^2.
The normal car has an energy is 0 *m + i * Vtreadmill^2
Remember that in the 1 second on the road they had the same energy and now the rocket car has much more energy when both are required to be equal and equal to the original 1 * m + 1 * i. There is no way a plane can behave differently then the car.
err, we are talking about how the energy is used. car torques the wheels to move forward, plane does not torque the wheel to move forward. Otherwise we would have no airplanes!
Energy isn't used it is converted from one form to another. Just explain how the plane gets the additional energy.
I would be very proud to nominate you for a Darwin award if you do.Originally posted by: dainthomas
Originally posted by: jandrews
Originally posted by: pnad
The plane is NOT stationary. That is the point. The treadmill is incapable of keeping a plane stationary.
so when you are running on a treadmill you feel the wind picking up and blowing in your face when at the gym? lmao, uh no.
If I was wearing a jet pack and wearing roller skates I would.
Originally posted by: NanoStuff
The plane will fly only as a result of the deadlock of the question. The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
In the real world there's also a latency between the plane's forward acceleration and the belt's compensation, giving the plane some theoretical escape route.
It makes no difference whether it's a car or plane on the belt in regards to it's ability to move forward for reasons that you're not about to understand now if you don't already.
A belt can and does prevent absolute forward movement without much difficulty by compensating for wheel rotation, this is regularly used in vehicle testing. The belt could very easily prevent the plane from moving had the question not implicitly required the plane to move. Those that say the plane will take off (which is what will happen presuming they do the test correctly, don't count on it), are greatly underestimating just how easily it could have not taken off.
Originally posted by: BlinderBomber
Originally posted by: NanoStuff
The plane will fly only as a result of the deadlock of the question. The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
In the real world there's also a latency between the plane's forward acceleration and the belt's compensation, giving the plane some theoretical escape route.
It makes no difference whether it's a car or plane on the belt in regards to it's ability to move forward for reasons that you're not about to understand now if you don't already.
A belt can and does prevent absolute forward movement without much difficulty by compensating for wheel rotation, this is regularly used in vehicle testing. The belt could very easily prevent the plane from moving had the question not implicitly required the plane to move. Those that say the plane will take off (which is what will happen presuming they do the test correctly, don't count on it), are greatly underestimating just how easily it could have not taken off.
Please explain what happens in this scenario:
-A plane takes off from a normal runway and leaves its landing gear extended.
-The plane circles around to a secondary runway which is a giant conveyor belt moving backward (ie, 180 degrees opposite the plane's forward motion) at the same ground speed the plane has (if the plane is flying at 180 mph, the conveyor is moving at 180 mph in the opposite direction).
-The plane, without slowing down, flies low enough that its landing gear touches the conveyor belt, but does not attempt to land.
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
Originally posted by: Cold Steel
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
I agree and always have. The plane will take off. But you missed the point of my post. The original question creates a paradox.
Originally posted by: PurdueRy
Originally posted by: Cold Steel
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
I agree and always have. The plane will take off. But you missed the point of my post. The original question creates a paradox.
Assume there is 1ns of compensation delay. Now your paradox is gone but the question remains.
Originally posted by: randay
Originally posted by: PurdueRy
Originally posted by: Cold Steel
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
I agree and always have. The plane will take off. But you missed the point of my post. The original question creates a paradox.
Assume there is 1ns of compensation delay. Now your paradox is gone but the question remains.
Assume the airplane is lighter then air and floats off as soon as the experiment starts. Also Assume that air is water and the airplane uses flippers to swim through the air. Like a turtle. Also assume that the treadmill is more like a recumbent bike or a hamster wheel.
Originally posted by: Cold Steel
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
I agree and always have. The plane will take off. But you missed the point of my post. The original question creates a paradox.
Originally posted by: Venix
Originally posted by: Cold Steel
Originally posted by: Nyati13
Originally posted by: Cold Steel
Originally posted by: NanoStuff
The conveyor belt will only move backwards if the plane moves forwards. The plane is therefore moving forwards.
This is the paradox of the original question.
Assume for arguments sake that the belt prevents the plane from moving. If the belt only moves when the plane moves and the belt is preventing the plane from moving, then the belt doesn't move because the plane isn't moving. If the belt doesn't move, the plane can move forward. But if the belt can prevent the plane from moving forward then the belt doesn't move because the plane isn't moving. If the belt doesn't move then the plane can move forward. But of the belt can prevent....... and on and on. Paradox.
There isn't any way the belt can hold the aircraft from moving. That's the whole point. It doesn't matter if the setup is "belt matches aircraft speed" or "belt matches wheel speed" either way, the belt cannot hold the aircraft back.
I agree and always have. The plane will take off. But you missed the point of my post. The original question creates a paradox.
"The conveyor matches the plane's forward speed" is not a paradox, it is a simple control system.
"The conveyor matches the plane's wheel speed" makes no sense, since an increase in the belt speed increases wheel speed, and vice versa.
The treadmill could restrict the plane's forward motion. The problem is, it would need to move at an incredibly fast speed.Originally posted by: PurdueRy
Originally posted by: Venix
"The conveyor matches the plane's forward speed" is not a paradox, it is a simple control system.
"The conveyor matches the plane's wheel speed" makes no sense, since an increase in the belt speed increases wheel speed, and vice versa.
Yup, the only people that have trouble with this is the people that somehow still picture the treadmill being able to counteract the plane's motion.
Originally posted by: Jeff7
The treadmill could restrict the plane's forward motion. The problem is, it would need to move at an incredibly fast speed.Originally posted by: PurdueRy
Originally posted by: Venix
"The conveyor matches the plane's forward speed" is not a paradox, it is a simple control system.
"The conveyor matches the plane's wheel speed" makes no sense, since an increase in the belt speed increases wheel speed, and vice versa.
Yup, the only people that have trouble with this is the people that somehow still picture the treadmill being able to counteract the plane's motion.
The wheels will have a certain amount of bearing friction, but the whole purpose of wheels is to have a small amount of friction. While it is a small amount of force acting against the plane, it is still present, and could be used to slow the plane and restrict its forward motion.
Second, there is the rotational inertia of the wheels to overcome. I think it was jagec who used this example: Put a wheel in space with a string tied to the perimeter. The string is analogous to the ground against the plane's wheel. Tug on the string. The wheel will not start spinning in one place - it will start spinning, but it will also begin to move toward you.
With both of these in mind, it would be "possible" to restrict the plane's forward motion using only the speed of the treadmill. The problem I see is that the treadmill would need to move so quickly that either the bearings would melt, or the tires would rip themselves apart. It is a simple control system, but not one that's really feasible to construct - unless you do away with the wheels, and use something like a plane on skis. Then there's obviously no rotational inertia to deal with, but much more friction.
So given the material limitations that restrict construction of a super-fast treadmill, in the real world, the plane's engine thrust would be able to overcome the small forces of the wheels' rotational inertia and bearing friction, and it takes off.
Originally posted by: Jeff7
The treadmill could restrict the plane's forward motion. The problem is, it would need to move at an incredibly fast speed.Originally posted by: PurdueRy
Originally posted by: Venix
"The conveyor matches the plane's forward speed" is not a paradox, it is a simple control system.
"The conveyor matches the plane's wheel speed" makes no sense, since an increase in the belt speed increases wheel speed, and vice versa.
Yup, the only people that have trouble with this is the people that somehow still picture the treadmill being able to counteract the plane's motion.
The wheels will have a certain amount of bearing friction, but the whole purpose of wheels is to have a small amount of friction. While it is a small amount of force acting against the plane, it is still present, and could be used to slow the plane and restrict its forward motion.
Second, there is the rotational inertia of the wheels to overcome. I think it was jagec who used this example: Put a wheel in space with a string tied to the perimeter. The string is analogous to the ground against the plane's wheel. Tug on the string. The wheel will not start spinning in one place - it will start spinning, but it will also begin to move toward you.
With both of these in mind, it would be "possible" to restrict the plane's forward motion using only the speed of the treadmill. The problem I see is that the treadmill would need to move so quickly that either the bearings would melt, or the tires would rip themselves apart. It is a simple control system, but not one that's really feasible to construct - unless you do away with the wheels, and use something like a plane on skis. Then there's obviously no rotational inertia to deal with, but much more friction.
So given the material limitations that restrict construction of a super-fast treadmill, in the real world, the plane's engine thrust would be able to overcome the small forces of the wheels' rotational inertia and bearing friction, and it takes off.