Will the Airplane Fly??????????

[nerbyoso]

It's an airplane, not a rocket. Even if it had thrust, it needs lift to take off! Thrust will only push it forward, but what happens here? Negligible yung friction and the conveyor belt instantly brings the velocity to zero dahil yun ang nakalagay sa condition ng tanong.

the question kasi will lead you to believe na yung conveyor belt is capable of exerting enough frinction on rolling/rotating airplane wheels to stop it from taking off...sabi nga ni niky sa sagot nya..e halos imposible na yun...boy you gonna need trmendous amount of energy to do that..the plane is using its propellers/jet and wings to fly and you are using only friction on its rolling wheels to keep it on the ground?

airplane, rocket pareho lang yan...the only difference is that an airplane needs to be fuel efficient to be able to travel long distances and carry loads at the same time thus the lower speed and use of runway.

[mbeige]

Ah, of course the plane's position does change! The runway is doing absolutely no opposing force. The engine works on the plane, the treadmill works on the wheels. End result, plane moves, eventually it reaches takeoff speed.

Your statement isn't "proof" because it assumes that the engines are doing absolutely nothing to the plane.

Ok let's analyze this.

The plane is sitting on the conveyor belt.

The conveyor belt pushes the plane and keeps it above the "runway".

The only point any force from the plane will go to is the wheels.

The only point any force from the conveyor belt will go to is the wheels.

If both surfaces are going opposite each other at the same speed, then the plane is not moving.

The engines keep pushing it against the wind.

So now there is wind? Akala ko sinabi mo kanina there is no wind?

[Alpha_One]

Kaya nga, there is NO wind going opposite in direction. Don't you realize that in order for a plane to take off, it needs lift. Once again you proved my point, since there is NO wind, there will be no lift.

And with your statement that the runway moves opposite the plane, if both move at opposite directions at the same speed, what happens to the plane? It remains at constant velocity (zero!).

There is no trick here. It's just simple physics.

There is a trick here, and it's still within simple physics. But it has absolutely nothing to do with the plane running against the runway!

Put it this way, you going on the freeway at 100KPH DOES NOT keep cars going the other direction at 100KPH!! The end result is that you pass by each other at 200KPH. It's exactly the same with the plane and the runway.

Also, I'm curious as to how you came up with the "no wind"/"air not moving" conclusion. Note that it's the ground that's moving against the plane, not the wind.

[mbeige]

the question kasi will lead you to believe na yung conveyor belt is capable of exerting enough frinction on rolling/rotating airplane wheels to stop it from taking off...sabi nga ni niky sa sagot nya..e halos imposible na yun...boy you gonna need trmendous amount of energy to do that..the plane is using its propellers/jet and wings to fly and you are using only friction on its rolling wheels to keep it on the ground?

airplane, rocket pareho lang yan...the only difference is that an airplane needs to be fuel efficient to be able to travel long distances and carry loads at the same time thus the lower speed and use of runway.

Dude, that was the original condition. Are you telling me that Alpha and Niky are talking about realistic worlds, while I am basing my answer on the question? Then I guess that's the only thing that makes sense!

Whether it is impossible or not, that was the given. And I am sticking with that.

the plane is using its propellers/jet and wings to fly and you are using only friction on its rolling wheels to keep it on the ground?

Ain't that the truth! The only difference between reality and this is that the runway is stationary and will NOT match the plane's speed in the opposite direction.

airplane, rocket pareho lang yan

Tell me, how does each one take off the ground? The plane uses Bernoulli's principle which states that the lower pressure above the wings will generate lift because the higher pressure below the wings will push it up (remember, pressure goes from high to low).

A rocket takes off using sheer thrust. The fins are just used to stabilize it and guide it along, NOT to generate lift. Otherwise, it would have been called a plane.

[nerbyoso]

sir, nakakita ka na ba ng trick na hinila yung table cloth pero yung mga pingan at yung baso hindi gumalaw sa ibawbaw ng table? for all we know, the speed of the conveyor may even make the non-running airplane stay in place because of weight and gravity...then add power to the plane...zoom it goes.

[niky]

No. The force from the engines goes to the plane in total.

The only given is that both surfaces are moving at the same speed, in opposite directions.

To reiterate my last post, to exert enough force on the plane to keep it stationary, the belt must be moving faster than the plane.

Again, this is based on the question, only, no other conditions given.

If the plane were driven by its wheels, it will remain stationary. But it's not. That's all.

[Alpha_One]

Ok let's analyze this.

The plane is sitting on the conveyor belt.

The conveyor belt pushes the plane and keeps it above the "runway".

The only point any force from the plane will go to is the wheels.

The only point any force from the conveyor belt will go to is the wheels.

If both surfaces are going opposite each other at the same speed, then the plane is not moving.



So now there is wind? Akala ko sinabi mo kanina there is no wind?

You're wrong in assuming that the plane's "force" goes to the wheels. The plane doesn't make any force, it gets its force from the thrust from engines. The wheels gets all its force from the conveyor belt.

The plane moves at 1MPH. The conveyor belt moves at 1MPH in the opposite direction. The plane gets a 1MPH wind across it's wings (clarify ko na ha!), the wheels just spin. Eventually the plane gets enough "wind" on its wings to take off and takes off.


When I said there is no wind, I meant that the wind isn't going to change it's velocity when the plane does. Planes take off perfectly fine in the real world without "wind". The engines push the plane forward and makes it's own "wind" on the wings. Your statement(s) is(are) completely fallacious in concluding that there cannot be wind against the plane.

[boybi]

There is a trick here, and it's still within simple physics. But it has absolutely nothing to do with the plane running against the runway!

Put it this way, you going on the freeway at 100KPH DOES NOT keep cars going the other direction at 100KPH!! The end result is that you pass by each other at 200KPH. It's exactly the same with the plane and the runway.

Also, I'm curious as to how you came up with the "no wind"/"air not moving" conclusion. Note that it's the ground that's moving against the plane, not the wind.

sir, the airplane is stationary with respect to it's environment because of the conveyor under its wheels. now where does the wind come from?

[mbeige]

There is a trick here, and it's still within simple physics. But it has absolutely nothing to do with the plane running against the runway!

Put it this way, you going on the freeway at 100KPH DOES NOT keep cars going the other direction at 100KPH!! The end result is that you pass by each other at 200KPH. It's exactly the same with the plane and the runway.

Also, I'm curious as to how you came up with the "no wind"/"air not moving" conclusion. Note that it's the ground that's moving against the plane, not the wind.

This is my last reply for the night, it's 3AM and I'm supposed to be in bed.

Your freeway analogy is NOT the same. Why? Because the cars are already moving, but in this case you're starting with a NON-moving body to be compared with a NON-moving body.

The ground is not moving against the plane in the real world, the plane moves against the ground. I did not say that the ground is moving against the wind! Where did you get that bit?

[boybi]

A plane is standing on a runway that can move (like a giant conveyor
belt). This conveyor has a control system that tracks the plane's
speed and tunes the speed of the conveyor to be exactly the same (but
in the opposite direction) instantly.

again and again, whatever force the wheels or the jet engines of the plane produce is negated by the conveyor that keeps the airplane stationary. you cannot produce any lift with a stationary object.

[mbeige]

When I said there is no wind, I meant that the wind isn't going to change it's velocity when the plane does. Planes take off perfectly fine in the real world without "wind". The engines push the plane forward and makes it's own "wind" on the wings. Your statement(s) is(are) completely fallacious in concluding that there cannot be wind against the plane.

Planes take off perfectly BECAUSE THE RUNWAY DOES NOT MOVE! But in this case, IT DOES! Hence, it does NOT take off AT ALL!

[mbeige]

sir, nakakita ka na ba ng trick na hinila yung table cloth pero yung mga pingan at yung baso hindi gumalaw sa ibawbaw ng table? for all we know, the speed of the conveyor may even make the non-running airplane stay in place because of weight and gravity...then add power to the plane...zoom it goes.

But it is stated that in the question, the conveyor belt matches the speed in the opposite direction! How many times will I say that? Read the original question!

[niky]

It's simply that you have to remove the preconception that the wheels and ground have anything to do with take-off.

Here's a simpler example. You've got a treadmill. You're running on it. The treadmill is matching your speed, so you stay in place, right? That's because you're exerting force on the treadmill (ground) with your wheels (feet).

Now say, you're an airplane. Your hands are your engines, and the hand rails of the treadmill represent the air. Your engines push or pull against the air, and no matter what speed the treadmill is going, you can go forward or backwards on it... even if it adjusts to move forwards or backwards at the speed your body is going. Your feet (wheels) have to move faster, but your body (airplane) moves at the same speed, thus, you can pull yourself forward on the treadmill, no matter how fast the treadmill is going!

[beachbum]

the airplane won't fly. it needs wind to fly. if only thrust is needed for a plane to fly, so you can take out the wings and just put the engine and it can fly pero hindi pwede di ba. a stationary object cannot create its own wind. even if it is propeller driven, it cant generate enough wind to create lift from the wings. that's why you will notice that the wing flaps are longer during takeoff and landing. to create lift.

[Alpha_One]

This is my last reply for the night, it's 3AM and I'm supposed to be in bed.

Your freeway analogy is NOT the same. Why? Because the cars are already moving, but in this case you're starting with a NON-moving body to be compared with a NON-moving body.

The ground is not moving against the plane in the real world, the plane moves against the ground. I did not say that the ground is moving against the wind! Where did you get that bit?

The freeway analogy is perfectly compatible with the airplane-runway situation. We've established that the wheels only freewheel when the plane and runway move (no bearing friction at all). This effectively "disconnects" the runway from the airplane, which makes them two independent bodies. Two cars running on opposite directions on the freeway are also independent bodies.

The ground trying to run in the opposite VELOCITY as the plane does NOT imply that the plane cannot get any velocity with respect to the air (i.e. get any wind).

Given:
Air velocity: 0 (This is our reference point. I'll use "air" to prevent any confusion this time)
Airplane velocity: 100

We can conclude at the point that the runway has a velocity of -100, given the premise. So:

Runway velocity: -100

Now, the crucial part:
Airplane speed with respect to the air: 100
Runway speed with respect to the air: 100
Airplane speed with respect to the runway: 200 (it doesn't cancel out. The plane pass each other at 200 in the same way two cars do on the freeway)

I didn't get any "ground moving against the wind bits". I just want you to explain how you came to the conclusion that if the runway runs against the plane, the plane can't run against the wind.

[mbeige]

But it is still stated that whatever increase in speed the plane incurs, the conveyor belt matches it in the opposite direction, instantly. So whatever force the plane exerts on the wind or air, the conveyor belt will match it in the opposite direction and the plane will remain stationary!

[Alpha_One]

Planes take off perfectly BECAUSE THE RUNWAY DOES NOT MOVE! But in this case, IT DOES! Hence, it does NOT take off AT ALL!

The speed which the runway runs, or even if it's going forwards or backwards, has absolutely nothing to do with the wind on the plane's wings!

Good night sir.

[mbeige]

The freeway analogy is perfectly compatible with the airplane-runway situation. We've established that the wheels only freewheel when the plane and runway move (no bearing friction at all). This effectively "disconnects" the runway from the airplane, which makes them two independent bodies. Two cars running on opposite directions on the freeway are also independent bodies.

The ground trying to run in the opposite VELOCITY as the plane does NOT imply that the plane cannot get any velocity with respect to the air (i.e. get any wind).

Given:
Air velocity: 0 (This is our reference point. I'll use "air" to prevent any confusion this time)
Airplane velocity: 100

We can conclude at the point that the runway has a velocity of -100, given the premise. So:

Runway velocity: -100

Now, the crucial part:
Airplane speed with respect to the air: 100
Runway speed with respect to the air: 100
Airplane speed with respect to the runway: 200 (it doesn't cancel out. The plane pass each other at 200 in the same way two cars do on the freeway)

I didn't get any "ground moving against the wind bits". I just want you to explain how you came to the conclusion that if the runway runs against the plane, the plane can't run against the wind.

See my previous post.

[Alpha_One]

But it is still stated that whatever increase in speed the plane incurs, the conveyor belt matches it in the opposite direction, instantly. So whatever force the plane exerts on the wind or air, the conveyor belt will match it in the opposite direction and the plane will remain stationary!

No it doesn't. The force the plane exerts on the air is not affected in any way by the force the ground exerts. Remember, the wheels effectively isolates the plane from the ground making them two completely independent bodies.

[boybi]

It's simply that you have to remove the preconception that the wheels and ground have anything to do with take-off.

in the real world, the wheels are just an aid for the jet engines to push the plane forward againts the ground. it is the speed of the airplane (generated by the jet engines) against the surrounding air that creates a lift for the airplane to take off.

but in this situation, the airplane's speed against the surrounding air is zero. why?!?!? BECAUSE IT IS STATIONARY!

Here's a simpler example. You've got a treadmill. You're running on it. The treadmill is matching your speed, so you stay in place, right? That's because you're exerting force on the treadmill (ground) with your wheels (feet).

Now say, you're an airplane. Your hands are your engines, and the hand rails of the treadmill represent the air. Your engines push or pull against the air, and no matter what speed the treadmill is going, you can go forward or backwards on it... even if it adjusts to move forwards or backwards at the speed your body is going. Your feet (wheels) have to move faster, but your body (airplane) moves at the same speed, thus, you can pull yourself forward on the treadmill, no matter how fast the treadmill is going!

because the handrails are attached to the treadmill. the air is not 'attached' to the ground or the conveyor.