That plane, and it taking off.

[JujuFish]

Originally posted by: LoKe

Originally posted by: Delbert
I havent read the whole thread. Well this one.
Sorry if this has already been posted.
It's a video of a float plane taking off from a trailer being pulled by a truck.
Similaritys?

No, because in that video the plane is actually moving; meaning, there is air flow.

On the conveyor belt, the plane moves as well. The thing with the video is that what it's on isn't moving in the opposite direction.

 

[imported_LoKe]

Originally posted by: JujuFish

Originally posted by: LoKe

Originally posted by: Delbert
I havent read the whole thread. Well this one.
Sorry if this has already been posted.
It's a video of a float plane taking off from a trailer being pulled by a truck.
Similaritys?

No, because in that video the plane is actually moving; meaning, there is air flow.

On the conveyor belt, the plane moves as well. The thing with the video is that what it's on isn't moving in the opposite direction.

If you put a plane on a conveyor belt and the speeds are matching in opposites; then the plane would stay in the middle of the belt. If the plane stays in the middle, it's not moving.

 

[JujuFish]

Originally posted by: LoKe

Originally posted by: JujuFish

Originally posted by: LoKe

Originally posted by: Delbert
I havent read the whole thread. Well this one.
Sorry if this has already been posted.
It's a video of a float plane taking off from a trailer being pulled by a truck.
Similaritys?

No, because in that video the plane is actually moving; meaning, there is air flow.

On the conveyor belt, the plane moves as well. The thing with the video is that what it's on isn't moving in the opposite direction.

If you put a plane on a conveyor belt and the speeds are matching in opposites; then the plane would stay in the middle of the belt. If the plane stays in the middle, it's not moving.

No, the plane would be moving in one direction, while the conveyor moves in another. The plane will accelerate, pick up enough speed, and take off. It would not stay in the middle because planes do not work like cars.

 

[cKGunslinger]

Originally posted by: Delbert
I havent read the whole thread. Well this one.
Sorry if this has already been posted.
It's a video of a float plane taking off from a trailer being pulled by a truck.
Similaritys?

Actually, no. That's really not analogous to the current discussion.

 

[cKGunslinger]

Originally posted by: LoKe

If you put a plane on a conveyor belt and the speeds are matching in opposites; then the plane would stay in the middle of the belt. If the plane stays in the middle, it's not moving.

You fail. :thumbsdown:

 

[NatePo717]

I say we send this to mythbusters and let them prove to all those who don't think the plane will take off that they are wrong.

 

[NanoStuff]

There's more to it than the plane taking off. In one instance of the question the plane will take off, and people who say the plane takes off in this case would be correct, however when you ask them why the plane takes off, they say the belt has no influence on the plane.

Seeing as how many otherwise intelligent people are having difficulty with this question, I'm unconvinced this is the one for the Mythbusters, they've screwed up with a whole lot less. On the other hand, it would be damn interesting to watch them duke it out over this one, so let's do it 🙂

 

[JujuFish]

Originally posted by: NanoStuff
There's more to it than the plane taking off. In one instance of the question the plane will take off, and people who say the plane takes off in this case would be correct, however when you ask them why the plane takes off, they say the belt has no influence on the plane.

Seeing as how many otherwise intelligent people are having difficulty with this question, I'm unconvinced this is the one for the Mythbusters, they've screwed up with a whole lot less. On the other hand, it would be damn interesting to watch them duke it out over this one, so let's do it 🙂

Proof of being a troll?

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff
There's more to it than the plane taking off. In one instance of the question the plane will take off, and people who say the plane takes off in this case would be correct, however when you ask them why the plane takes off, they say the belt has no influence on the plane.

Seeing as how many otherwise intelligent people are having difficulty with this question, I'm unconvinced this is the one for the Mythbusters, they've screwed up with a whole lot less. On the other hand, it would be damn interesting to watch them duke it out over this one, so let's do it 🙂

Proof of being a troll?

Proof of being right 😉

 

[JujuFish]

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
There's more to it than the plane taking off. In one instance of the question the plane will take off, and people who say the plane takes off in this case would be correct, however when you ask them why the plane takes off, they say the belt has no influence on the plane.

Seeing as how many otherwise intelligent people are having difficulty with this question, I'm unconvinced this is the one for the Mythbusters, they've screwed up with a whole lot less. On the other hand, it would be damn interesting to watch them duke it out over this one, so let's do it 🙂

Proof of being a troll?

Proof of being right 😉

Let's see. Here, you admit the plane takes off. Yet, you've been arguing against such an occurrence. That sure sounds to me like you're being a troll.

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
There's more to it than the plane taking off. In one instance of the question the plane will take off, and people who say the plane takes off in this case would be correct, however when you ask them why the plane takes off, they say the belt has no influence on the plane.

Seeing as how many otherwise intelligent people are having difficulty with this question, I'm unconvinced this is the one for the Mythbusters, they've screwed up with a whole lot less. On the other hand, it would be damn interesting to watch them duke it out over this one, so let's do it 🙂

Proof of being a troll?

Proof of being right 😉

Let's see. Here, you admit the plane takes off. Yet, you've been arguing against such an occurrence. That sure sounds to me like you're being a troll.

Nope, I never diagreed the plane will take off in this case. I was arguing that the plane will NOT take off if the reverse velocity of the belt equals that of the angular velocity of the wheels, which is one interpretation to the question. This is used to illustrate that while the plane WILL take off in the scenario of compensating for linear movement, it will do so with much greater difficulty.

 

[JujuFish]

Originally posted by: NanoStuff
Nope, I never diagreed the plane will take off in this case. I was arguing that the plane will NOT take off if the reverse velocity of the belt equals that of the angular velocity of the wheels, which is one interpretation to the question. This is used to illustrate that while the plane WILL take off in the scenario of compensating for linear movement, it will do so with much greater difficulty.

Unfortunately, the scenario where you choose to say the plane does not take off is an impossibility. Since it doesn't follow the laws of physics, there's no way you can claim that it does or doesn't take off. For all we know, in this imaginary world, flying is a matter of having any movement at all, or maybe it can never happen.

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff
Nope, I never diagreed the plane will take off in this case. I was arguing that the plane will NOT take off if the reverse velocity of the belt equals that of the angular velocity of the wheels, which is one interpretation to the question. This is used to illustrate that while the plane WILL take off in the scenario of compensating for linear movement, it will do so with much greater difficulty.

Unfortunately, the scenario where you choose to say the plane does not take off is an impossibility. Since it doesn't follow the laws of physics, there's no way you can claim that it does or doesn't take off. For all we know, in this imaginary world, flying is a matter of having any movement at all, or maybe it can never happen.

I don't believe the laws of physics dictates that a belt cannot move in reverse at the rotational speed of the wheels.

Look at the earth analogy one more time, exact same thing on a larger scale. You're an observer in space, the earth flies past you at 1000km/h with a plane sitting on the ground. Both the earth and plane move past you at 1000km/h. If the plane accelerates on the earth to 1000km/h, the plane is moving at 1000km/h on the earth, but to this space oberver, the plane is standing still, and now only the earth is moving past while the plane advanced forward on earth while not changing it's distance from you.

Now all you have to do is replace the earth with a belt and the space observer with a guy sitting on a bench on a static surface watching the action take place, you end up with the exact same thing. The plane IS moving forward, but only on the belt.

 

[JujuFish]

Originally posted by: NanoStuff
I don't believe the laws of physics dictates that a belt cannot move in reverse at the rotational speed of the wheels.

Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

Look at the earth analogy one more time, exact same thing on a larger scale. You're an observer in space, the earth flies past you at 1000km/h with a plane sitting on the ground. Both the earth and plane move past you at 1000km/h. If the plane accelerates on the earth to 1000km/h, the plane is moving at 1000km/h on the earth, but to this space oberver, the plane is standing still, and now only the earth is moving past while the plane advanced forward on earth while not changing it's distance from you.

Now all you have to do is replace the earth with a belt and the space observer with a guy sitting on a bench on a static surface watching the action take place, you end up with the exact same thing. The plane IS moving forward, but only on the belt.

These two are not the same thing for a variety of reasons. One is angular momentum of the plane. It's not there in the conveyor belt example. There are other reasons, but the point is that these are not the same.

 

[Suspicious-Teach8788]

Vote here discuss in the old thread plz

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff
I don't believe the laws of physics dictates that a belt cannot move in reverse at the rotational speed of the wheels.

Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

Look at the earth analogy one more time, exact same thing on a larger scale. You're an observer in space, the earth flies past you at 1000km/h with a plane sitting on the ground. Both the earth and plane move past you at 1000km/h. If the plane accelerates on the earth to 1000km/h, the plane is moving at 1000km/h on the earth, but to this space oberver, the plane is standing still, and now only the earth is moving past while the plane advanced forward on earth while not changing it's distance from you.

Now all you have to do is replace the earth with a belt and the space observer with a guy sitting on a bench on a static surface watching the action take place, you end up with the exact same thing. The plane IS moving forward, but only on the belt.

These two are not the same thing for a variety of reasons. One is angular momentum of the plane. It's not there in the conveyor belt example. There are other reasons, but the point is that these are not the same.

Angular momentum of the plane? Ok, pretend the world is flat, it doesn't matter.

 

[JujuFish]

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
I don't believe the laws of physics dictates that a belt cannot move in reverse at the rotational speed of the wheels.

Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

Look at the earth analogy one more time, exact same thing on a larger scale. You're an observer in space, the earth flies past you at 1000km/h with a plane sitting on the ground. Both the earth and plane move past you at 1000km/h. If the plane accelerates on the earth to 1000km/h, the plane is moving at 1000km/h on the earth, but to this space oberver, the plane is standing still, and now only the earth is moving past while the plane advanced forward on earth while not changing it's distance from you.

Now all you have to do is replace the earth with a belt and the space observer with a guy sitting on a bench on a static surface watching the action take place, you end up with the exact same thing. The plane IS moving forward, but only on the belt.

These two are not the same thing for a variety of reasons. One is angular momentum of the plane. It's not there in the conveyor belt example. There are other reasons, but the point is that these are not the same.

Angular momentum of the plane? Ok, pretend the world is flat, it doesn't matter.

Assuming the a giant conveyor belt the size of the earth, let me quote myself:

Originally posted by: JujuFish
Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
I don't believe the laws of physics dictates that a belt cannot move in reverse at the rotational speed of the wheels.

Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

Look at the earth analogy one more time, exact same thing on a larger scale. You're an observer in space, the earth flies past you at 1000km/h with a plane sitting on the ground. Both the earth and plane move past you at 1000km/h. If the plane accelerates on the earth to 1000km/h, the plane is moving at 1000km/h on the earth, but to this space oberver, the plane is standing still, and now only the earth is moving past while the plane advanced forward on earth while not changing it's distance from you.

Now all you have to do is replace the earth with a belt and the space observer with a guy sitting on a bench on a static surface watching the action take place, you end up with the exact same thing. The plane IS moving forward, but only on the belt.

These two are not the same thing for a variety of reasons. One is angular momentum of the plane. It's not there in the conveyor belt example. There are other reasons, but the point is that these are not the same.

Angular momentum of the plane? Ok, pretend the world is flat, it doesn't matter.

Assuming the a giant conveyor belt the size of the earth, let me quote myself:

Originally posted by: JujuFish
Oh they can, as long as the engines are on very low, providing just enough thrust to overcome the small amount of friction and angular momentum. However, since once the thrust gets a little more, the wheels will start spinning faster, and the conveyor belt will not be able to stop it.

Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

 

[JujuFish]

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

 

[Suspicious-Teach8788]

You do realize that the conveyor belt provides 0 force if you assume the bearings are close to frictionless...

And that's what you pretty much are supposed to assume for a problem like this...

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

It wouldn't because the belt is moving in direct proportion to the wheels of the plane. So the belt only accelerates if the wheels rotate faster, and the wheels will rotate faster if thrust is applied to the plane. 'Torque' would only be applied to the wheels by the belt if the belt attempted to rotate faster than the wheels.

This is shown by the fact that the plane has to apply thrust in order for the belt to move. If the plane sits still, so does the belt, as such it does not attempt to accelerate the wheels itself, only compensate.

Originally posted by: DLeRium
You do realize that the conveyor belt provides 0 force if you assume the bearings are close to frictionless...

No I don't because it's not true.

 

[JujuFish]

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

It wouldn't because the belt is moving in direct proportion to the wheels of the plane. So the belt only accelerates if the wheels rotate faster, and the wheels will rotate faster if thrust is applied to the plane. 'Torque' would only be applied to the wheels by the belt if the belt attempted to rotate faster than the wheels.

No, once thrust is applied, the plane will move forward. The conveyor will attempt to move faster in order to match the wheels, and in doing so, will apply a torque to those wheels.

This is shown by the fact that the plane has to apply thrust in order for the belt to move. If the plane sits still, so does the belt, as such it does not attempt to accelerate the wheels itself, only compensate.

This doesn't show anything.

 

[NanoStuff]

Originally posted by: JujuFish

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

It wouldn't because the belt is moving in direct proportion to the wheels of the plane. So the belt only accelerates if the wheels rotate faster, and the wheels will rotate faster if thrust is applied to the plane. 'Torque' would only be applied to the wheels by the belt if the belt attempted to rotate faster than the wheels.

No, once thrust is applied, the plane will move forward. The conveyor will attempt to move faster in order to match the wheels, and in doing so, will apply a torque to those wheels.

Even if we assume that it does infact apply torque, the plane still won't take off if the belt always matches the rotation of the wheels. Regardless of what forces are in play, if the wheel does not rotate faster than the belt, the wheel does not advance forward.

 

[PurdueRy]

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

It wouldn't because the belt is moving in direct proportion to the wheels of the plane. So the belt only accelerates if the wheels rotate faster, and the wheels will rotate faster if thrust is applied to the plane. 'Torque' would only be applied to the wheels by the belt if the belt attempted to rotate faster than the wheels.

No, once thrust is applied, the plane will move forward. The conveyor will attempt to move faster in order to match the wheels, and in doing so, will apply a torque to those wheels.

Even if we assume that it does infact apply torque, the plane still won't take off if the belt always matches the rotation of the wheels. Regardless of what forces are in play, if the wheel does not rotate faster than the belt, the wheel does not advance forward.

The wheels DOES rotate faster than the belt...double it in face. YOU interpreted the question incorrectly when you decided to make the post. If you look at this question around the internet it CLEARLY says the speed of the plane itself. Not the rotation speed of the plane. As if this was not true, as has been mentioned, you would introduce a situation that is unstable.

so....plane starts moving when engines turn on...lets say 1 MPH....treadmill moves 1 MPH backwards...wheels rotate at 2 MPH...plane takes off.

 

[Suspicious-Teach8788]

Originally posted by: NanoStuff

Originally posted by: JujuFish

Originally posted by: NanoStuff
Ok well... did you consider that if the wheels start spinning faster, the belt also starts moving back faster?

This would place a torque on the wheels, spinning them even faster.

It wouldn't because the belt is moving in direct proportion to the wheels of the plane. So the belt only accelerates if the wheels rotate faster, and the wheels will rotate faster if thrust is applied to the plane. 'Torque' would only be applied to the wheels by the belt if the belt attempted to rotate faster than the wheels.

This is shown by the fact that the plane has to apply thrust in order for the belt to move. If the plane sits still, so does the belt, as such it does not attempt to accelerate the wheels itself, only compensate.

Originally posted by: DLeRium
You do realize that the conveyor belt provides 0 force if you assume the bearings are close to frictionless...

No I don't because it's not true.

How is that not true. When you use rollers in statics classes, you assume only upward forces only. No horizontal forces. Frictionless bearings = 0 force by the conveyor belt. The only force on the wheels results in pure rotation and 0 translational force. Thus your energy by the conveyor belt is stored only in rotational energy and none of it goes into KE = 1/2mv^2.