physics fun

[grendel]

A plane is standing on runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in opposite direction).

The question is:

Will the plane take off or not? Will it be able to run up and take off?

[Steeda Snakes]

No.

Aerodynamics requires the movement of air around an object to create lift. An airplane wing is designed so that the air moves faster under the wing, than it does over the wing. This creates lift.

The airplane is on a conveyor belt (i.e. treadmill). Therefore, the plane is under power, but remains in a stationary position. The lack of forward movement equals a lack of air movement around the wing. No air movement around the wing equals no lift.

Your welcome, now finish your homework and go to bed! Damn, step children!!!! Oh yea, HAHA

[1SS2NV]

No.

Aerodynamics requires the movement of air around an object to create lift. An airplane wing is designed so that the air moves faster under the wing, than it does over the wing. This creates lift.

The airplane is on a conveyor belt (i.e. treadmill). Therefore, the plane is under power, but remains in a stationary position. The lack of forward movement equals a lack of air movement around the wing. No air movement around the wing equals no lift.

Your welcome, now finish your homework and go to bed! Damn, step children!!!! Oh yea, HAHA

If the plane is standing still then the belt is not moving, Am I right? The belt is only going to match the speed of the plane. If the plane moves foward, which will need air to move or thrust to move forward. Then the belt is going to move.
I admit it took me a good a couple of hours to get my head round this, but now I've seen the light it's just so obvious - the difficulty is in explaining it simply.

First, All you need to know is that there is such a thing as a plane, that it goes really fast, and once it reaches a certain speed it can take off and fly. The only remotely technical thing is that the engines push the plane through the air - they do not drive the wheels, the wheels will just spin freely in whatever direction you choose to push the plane.

Also, a concept to help understanding - two cars pass each other on the motorway, one travelling north at 50mph, the other travelling south at 50mph. Both moving at the same speed but in opposite directions, so their speed relative to each other is 100mph (ie they are moving apart at a rate of 100mph).

So to the puzzle. I think it is best to visualise it as if you are watching the plane from the control tower, and let's imagine also that the plane wants to take off from the left to right. The plane is moving, the puzzle states that clearly. It doesn't matter what speed but let's say 10mph. The puzzle then tells us that the conveyor always matches the speed of the plane but travelling in the opposite direction. So we know that at this point the conveyor must be moving at 10 mph in the opposite direction (right to left). So we (from the control tower) see the plane moving at 10mph but the plane is also moving at 20mph relative to the conveyor (ie the wheels - remember they spin freely - are rotating at a rate equivalent to 20mph. So, whatever the take off speed is (140 MPH) the plane simply accelerates to that speed (relative to our fixed point in the control tower) and takes off. The wheels will be spinning at twice the planes speed to compensate for the motion of the conveyor. Another logical thing to think about is the Fucking wheel speed this plane will have. Those fucking wheel better be bad ass.

Either way THE PLANE WILL FLY!!!

[grendel]

it wasnt homework, it was posted on another forum and it was fun to watch everyone argue

[DropTopDrifter]

Umm...like steeda said....it's the aerodymanics of the wings that allows it to fly. The wheel speed has nothing to do w/ it. That is why some planes can lift off w/ much less speed then oh say a huge 757 commercial airliner.
That is why aircraft carriers use a catapult launch system....the jet is at near full burn before being catapulted off the flight deck....and even then...the sudden wind gust from the drop off the deck is what allows it to fly out so easily.

the theory of relative positions is not applicable to this situation.


here's a new quesiton for you.
If a train is traveling at near the speed of light...and a person on that plain fires a pistol straight ahead....does that bullet attain a speed faster then the speed of light ?

[Bulldog Stang]

here's a new quesiton for you.
If a train is traveling at near the speed of light...and a person on that plain fires a pistol straight ahead....does that bullet attain a speed faster then the speed of light ?


That answer would be yes, but only for a second or so before the wind resistance slows the bullet down.

Im also agree with Snakes on this one..... You have to have the lift....

[DropTopDrifter]

Speed of light...thus anything traveling faster then the speed of light would become pure energy...if it was possible...but it's not since physics says that nothing can go faster then the speed of light.

[grendel]

lets see some other answers

[b-wake-racing]

the planes center of gravity would be shifted due to the force of the wind concurrence and air temperature thus creating a uneven balance of enomolies. would it fly? well, this all depends on the amount of humidity in the air

[grendel]

you nailed it

[1SS2NV]

By the time the plane even reaches the speed needed to fly the tires would be moving so fast that they would get so hot and would melt and the plane will lose control crash, burn, and all the people would die.!! Anyways who gives a shit.

[Bulldog Stang]

By the time the plane even reaches the speed needed to fly the tires would be moving so fast that they would get so hot and would melt and the plane will lose control crash, burn, and all the people would die.!! Anyways who gives a shit.


HAHA... Yellow.. Im with him... !!!! ... LOL

[Steeda Snakes]

If the plane is standing still then the belt is not moving, Am I right? The belt is only going to match the speed of the plane. If the plane moves foward, which will need air to move or thrust to move forward. Then the belt is going to move.
I admit it took me a good a couple of hours to get my head round this, but now I've seen the light it's just so obvious - the difficulty is in explaining it simply.

First, All you need to know is that there is such a thing as a plane, that it goes really fast, and once it reaches a certain speed it can take off and fly. The only remotely technical thing is that the engines push the plane through the air - they do not drive the wheels, the wheels will just spin freely in whatever direction you choose to push the plane.

Also, a concept to help understanding - two cars pass each other on the motorway, one travelling north at 50mph, the other travelling south at 50mph. Both moving at the same speed but in opposite directions, so their speed relative to each other is 100mph (ie they are moving apart at a rate of 100mph).

So to the puzzle. I think it is best to visualise it as if you are watching the plane from the control tower, and let's imagine also that the plane wants to take off from the left to right. The plane is moving, the puzzle states that clearly. It doesn't matter what speed but let's say 10mph. The puzzle then tells us that the conveyor always matches the speed of the plane but travelling in the opposite direction. So we know that at this point the conveyor must be moving at 10 mph in the opposite direction (right to left). So we (from the control tower) see the plane moving at 10mph but the plane is also moving at 20mph relative to the conveyor (ie the wheels - remember they spin freely - are rotating at a rate equivalent to 20mph. So, whatever the take off speed is (140 MPH) the plane simply accelerates to that speed (relative to our fixed point in the control tower) and takes off. The wheels will be spinning at twice the planes speed to compensate for the motion of the conveyor. Another logical thing to think about is the Fucking wheel speed this plane will have. Those fucking wheel better be bad ass.

Either way THE PLANE WILL FLY!!!

So now that we know what Sage from PhysOrg.com thinks, what do you think?

Check about halfway down for Sage's post. HAHA (http://forum.physorg.com/index.php?showtopic=2417&st=225)

I can say that my first response to this question was made utilizing my own deductive reasoning and what I rememered from my college physics classes.

After reading the above post, I thought about it for a moment and did a little more research. That is when I found the "interesting" link above.

Apparently, this is a topic of great debate out on the web. The problem is trying to get the reader to realize that an aircraft pushes against the wind. Therefore, the plane will fly.

I am still not completely convinced. The "Plane will fly" group states that the wheels spin freely. My question is; What about gravity? In my example, I will use a fully loaded 737. This aircraft must achieve an airspeed of approximately 180 mph for take-off. On a completely calm day airspeed will equal ground speed. Gravity will still be exerting her force on the aircraft until the lift-off speed is reached. So, from 0 to 180mph of ground speed, how are the wheels spinning freely? A fully-loaded 737 must weigh quite a bit.

With a light aircraft, I can possibly see how the plane might eventually take-off. The gravitational force on the aircraft would be far less.

Scientific evidence through experimentation is what I would believe, and not a toy airplane on an exercise treadmill. As far as how fast the wheels of the 737 would be turning just prior to take-off, if it could take-off at all, would be 360 mph!!!!!! So, I don't believe we will see this experiment anytime soon.

Also, some members of other boards believe that depending on how the question is interepeted, there are three possible solutions. "The Plane will not Fly" is one solution, and "the plane will fly" accounts for the other two.