Plane

[Swango1980]

But the plane is stationary in relation to the surrounding air so how would there be any lift generated….

View attachment 56876

That is why it is a teaser, because it is easy to jump to that assumption as I did when I first read it.

But, a plane can't be stationary relative to the air, because it is thrust forward against the air. It doesn't use grund forces to propel forwards.

The plane will take off, as it is using the air, not ground, to push against.

I suppose the question to ask is that is it actually possible for the treadmill and wheels to be moving at the same speed in opposite directions? When the plane uses its engines to take off, and it accelerates down runway, the treadmill will speed up. But the wheels react to the ground and speed of plane, so they will speed up faster. Theoretically the speed of treadmill can't ever catch up with speed of wheels, because plane is always thrust forward relative to air

 

[Swango1980]

And you don’t feel a breeze on a treadmill

I do. But only because it has a fan

 

[Deleted member 35927]

Because it is not moving. It is the same as running on a treadmill, you don’t move. Why would the plane be any different?

Also, engine provide thrust, this acts against drag and causes the aircraft to move forward. Engines do not provide lift, this is produced by the airflow over the wings, as shown above.

I don't move because I am using my feet and legs in direct counter to the treadmill. A jet plane is using it engines to interact with the air not the treadmill.

 

[Deleted member 36735]

I don't move because I am using my feet and legs in direct counter to the treadmill. A jet plane is using it engines to interact with the air not the treadmill.

And the scenario tells us that the conveyor belt counteracts the forward motion by moving at the same speed as the wheels in the opposite direction...
The plane is not moving forward.

 

[Deleted member 35927]

The WHOLE POINT of the question is that the plane isn't moving due to the conveyor belt
That is what you don't understand.

It matches the speed of the planes wheels, as the wheels are not need to propel the plane it matters not. At no point does it say anything about the plane not moving. Your just jumping to a wrong conclusion

 

[Deleted member 35927]

And the scenario tells us that the conveyor belt counteracts the forward motion by moving at the same speed as the wheels in the opposite direction...
The plane is not moving forward.

Of the wheels

 

[Neilds]

I don't move because I am using my feet and legs in direct counter to the treadmill. A jet plane is using it engines to interact with the air not the treadmill.

What bit of “ engines don’t provide lift” are you struggling with?

 

[Swango1980]

Looking at the picture on the OP, the actual answer will be the plane will not take off. But, nothing to do with speed of conveyor belt.

If the plane tries to take off, it WILL move forwards, because the conveyor belt cannot act as a brake to counter thrust on air.

However, it would clearly fall off the front of the belt and just crash

 

[Neilds]

It matches the speed of the planes wheels, as the wheels are not need to propel the plane it matters not. At no point does it say anything about the plane not moving. Your just jumping to a wrong conclusion

But how is the plane moving?

 

[Swango1980]

What bit of “ engines don’t provide lift” are you struggling with?

They provide forward momentum. The wings provide lift

 

[Deleted member 35927]

What bit of “ engines don’t provide lift” are you struggling with?

The same bit about the wheels don't provide drive

 

[Deleted member 36735]

Of the wheels

I'll take this very slowly for you in non technical language....

Normally.....the engines create a thrust that has a force on the plane, the wheels allow the plane to move forward by rolling over the ground.

In the scenario you have posted, the "ground" is actually a conveyor belt moving in the opposite direction, hence the plane is "moving forward" in relation to the belt but not in relation to the actual ground, hence it is EXACTLY the same as a person on a treadmill.

I honestly can't believe anyone who's not having a wind-up can't see this.

 

[Neilds]

The same bit about the wheels don't provide drive

But they don’t! They just freewheel.

 

[Deleted member 35927]

But they don’t! They just freewheel.

Exactly!!!!!!!

 

[Fade and Die]

Why is it stationary? It's moving forward as a consequence of the jet engines.

Nope.

 

[Deleted member 35927]

I'll take this very slowly for you in non technical language....

Normally.....the engines create a thrust that has a force on the plane, the wheels allow the plane to move forward by rolling over the ground.

In the scenario you have posted, the "ground" is actually a conveyor belt moving in the opposite direction, hence the plane is "moving forward" in relation to the belt but not in relation to the actual ground, hence it is EXACTLY the same as a person on a treadmill.

I honestly can't believe anyone who's not having a wind-up can't see this.

The engines give it thrust to move through the air not along the ground. Im amazed more don't see how obvious this is.

 

[Deleted member 35927]

Of course it's moving , the jets are powering it

Nope

 

[Swango1980]

I'll take this very slowly for you in non technical language....

Normally.....the engines create a thrust that has a force on the plane, the wheels allow the plane to move forward by rolling over the ground.

In the scenario you have posted, the "ground" is actually a conveyor belt moving in the opposite direction, hence the plane is "moving forward" in relation to the belt but not in relation to the actual ground, hence it is EXACTLY the same as a person on a treadmill.

I honestly can't believe anyone who's not having a wind-up can't see this

It isn't the same as a person on a treadmill

A person on a treadmill uses their legs to create drive against the ground.

A plane uses its engines to create drive against the air.

If a plane tries to take off, there is no treadmill in the world that is going to stop it moving forwards (even if someone built a really really big one)

 

[Deleted member 36735]

If a plane tries to take off, there is no treadmill in the world that is going to stop it moving forwards (even if someone built a really really big one)

Lol of course.
But that is exactly what the scenario says.

 

[Neilds]

The engines give it thrust to move through the air not along the ground. Im amazed more don't see how obvious this is.

Please explain in simple terms, how air is moving across the wings to provide lift? The plane will be stationary, in relation to the ground, as any forward motion (caused by the engines thrust) is counteracted by the reverse action of the treadmill- as stated in the original post.