That plane, and it taking off.

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smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: PurdueRy
Originally posted by: smack Down
Originally posted by: Yossarian
Originally posted by: smack Down
No that is what the problem states. It can not be incorrect.

That is why there is no correct answer to the problem. As written, it is an impossible situation. The belt can't compensate for the rotation of the wheels, yet the problem states it does. The result is multiple threads with hundreds of posts.

It doesn't need to be possible to ask what would happen. It comes down to asking can a plane take off that can't move the answer is that it can't. Why and how it can't move doesn't really matter.

Yet you cannot prove your theory with physics...

The plane can move and I have provided all you need to know...yet you are unwilling to learn it seems.

The question states the plane doesn't move that is a given and doesn't need to be proven.
 

JujuFish

Lifer
Feb 3, 2005
11,432
1,052
136
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
Forward implies linear velocity, not angular velocity.
 

smack Down

Diamond Member
Sep 10, 2005
4,507
0
0
Originally posted by: JujuFish
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
Forward implies linear velocity, not angular velocity.

The op has already been established as an idiot.

Notice the other bolded words. Clearly the op is talking about the rotation of the wheels moving forward on the treadmill. He doesn't mean forward as in the forward movement of the whole plane.
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: smack Down
Originally posted by: JujuFish
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
Forward implies linear velocity, not angular velocity.

The op has already been established as an idiot.

Notice the other bolded words. Clearly the op is talking about the rotation of the wheels moving forward on the treadmill. He doesn't mean forward as in the forward movement of the whole plane.

ok then just humor us and answer the version we are interested in
 

JujuFish

Lifer
Feb 3, 2005
11,432
1,052
136
Originally posted by: smack Down
Originally posted by: JujuFish
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
Forward implies linear velocity, not angular velocity.

The op has already been established as an idiot.

Notice the other bolded words. Clearly the op is talking about the rotation of the wheels moving forward on the treadmill. He doesn't mean forward as in the forward movement of the whole plane.

I see the other bolded words. "Clearly" it does not say that the belt moves in reverse exactly as fast as the wheels angular velocity. Angular velocity does not necessitate moving forward, whereas linear velocity does.
 

NanoStuff

Banned
Mar 23, 2006
2,981
1
0
Originally posted by: smack Down
Originally posted by: JujuFish
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
Forward implies linear velocity, not angular velocity.

The op has already been established as an idiot.

Notice the other bolded words. Clearly the op is talking about the rotation of the wheels moving forward on the treadmill. He doesn't mean forward as in the forward movement of the whole plane.
I'm the OP, so perhaps I should tell you what I'm talking about. I'm talking about you being full of ******. There I said it, goddamnit, someone had to. Ok, now where's my cookie?
 

AlienCraft

Lifer
Nov 23, 2002
10,539
0
0
Originally posted by: PurdueRy
Originally posted by: smack Down
Originally posted by: JujuFish
Originally posted by: smack Down
No the op post was orginally #1. Notice how 1 comes before 2 in the number system. People were talking about 2 because they can't compreand 1.

Actually, the original original post (how's that for seemingly redundant? :p) was condition two. Notice the bolded word:

Originally posted by: NanoStuff
The plane increases it's thrust and the wheels begin to rotate. The belt compensates for the rotation of the wheels in reverse, as in the belt moves in reverse exactly as fast as the wheels move forward.
If the plane can acheive forward travel at a speed sufficient to flow air across the wings such that it exceeds the takeoff velocity for that wing and body, it will take off.

smack Down more eloquently stated my misunderstandings of the parameters of the question originally the original original point of debate. I may have one too many originals in there, though I'm sure you'll interprete it the way that suits you best.:D
Forward implies linear velocity, not angular velocity.
Velocity, schmelocity... Are we talking about movement between two points in space as defined by the end of the conveyor or treadmill, or does this resemble in any way an Automotive Dyno?

The op has already been established as an idiot.

Notice the other bolded words. Clearly the op is talking about the rotation of the wheels moving forward on the treadmill. He doesn't mean forward as in the forward movement of the whole plane.

ok then just humor us and answer the version we are interested in
Who flippin cares anymore?
 
Feb 19, 2001
20,155
23
81
Originally posted by: OvErHeAtInG
Originally posted by: UlricT
WTF guys... the planes wheels are free-rolling. It does NOT drive the plane. The wheels will just spin twice as fast as the plane is moving forward (plane speed + conveyor belt speed)!

OK this is a great example of why seemingly intelligent people actually think the plane would take off. They misread the question and think the plane is actually moving relative to the air.

* If the plane is moving (fast enough) relative to the atmosphere, it will generate lift and take off.
* If the plane is not moving (fast enough) relative to atmosphere, it will not generate lift and take off.

See? Not so complicated. No differential equations, no general relativity, no damn Lorentz transformation. :roll:

The question, as I originally read it on ATOT months ago (maybe year+) stated that the speed of the conveyor would always match the speed of the plane relative to the conveyor. Meaning that the plane won't go anywhere relative to the atmosphere. However, if you wish to read the (very poorly worded) question as allowing for the increased velocity of the plane without a corresponding increase relative to the conveyor belt, you would believe that the plane could take off.

If the conveyor matches the speed of the plane, it does NOT mean the plane won't go anywhere relative to the atmosphere.

How about this? vplane = 100 m/s, vconveyor = -100 m/s. With respect to the ground, both parts are moving, but the plane takes off. Ch-Ching.

Did we misread? Nope. Did you misinterpret the question? Yes. Did you not understand the physics thats going on? Yes.

QED.
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: DLeRium
Originally posted by: OvErHeAtInG
Originally posted by: UlricT
WTF guys... the planes wheels are free-rolling. It does NOT drive the plane. The wheels will just spin twice as fast as the plane is moving forward (plane speed + conveyor belt speed)!

OK this is a great example of why seemingly intelligent people actually think the plane would take off. They misread the question and think the plane is actually moving relative to the air.

* If the plane is moving (fast enough) relative to the atmosphere, it will generate lift and take off.
* If the plane is not moving (fast enough) relative to atmosphere, it will not generate lift and take off.

See? Not so complicated. No differential equations, no general relativity, no damn Lorentz transformation. :roll:

The question, as I originally read it on ATOT months ago (maybe year+) stated that the speed of the conveyor would always match the speed of the plane relative to the conveyor. Meaning that the plane won't go anywhere relative to the atmosphere. However, if you wish to read the (very poorly worded) question as allowing for the increased velocity of the plane without a corresponding increase relative to the conveyor belt, you would believe that the plane could take off.

If the conveyor matches the speed of the plane, it does NOT mean the plane won't go anywhere relative to the atmosphere.

How about this? vplane = 100 m/s, vconveyor = -100 m/s. With respect to the ground, both parts are moving, but the plane takes off. Ch-Ching.

Did we misread? Nope. Did you misinterpret the question? Yes. Did you not understand the physics thats going on? Yes.

QED.

Dude, he figured it out in a future post:


Originally posted by: OvErHeAtInG
Originally posted by: PurdueRy
Originally posted by: OvErHeAtInG
Originally posted by: UlricT
WTF guys... the planes wheels are free-rolling. It does NOT drive the plane. The wheels will just spin twice as fast as the plane is moving forward (plane speed + conveyor belt speed)!

OK this is a great example of why seemingly intelligent people actually think the plane would take off. They misread the question and think the plane is actually moving relative to the air.

* If the plane is moving (fast enough) relative to the atmosphere, it will generate lift and take off.
* If the plane is not moving (fast enough) relative to atmosphere, it will not generate lift and take off.

See? Not so complicated. No differential equations, no general relativity, no damn Lorentz transformation. :roll:

The question, as I originally read it on ATOT months ago (maybe year+) stated that the speed of the conveyor would always match the speed of the plane relative to the conveyor. Meaning that the plane won't go anywhere relative to the atmosphere. However, if you wish to read the (very poorly worded) question as allowing for the increased velocity of the plane without a corresponding increase relative to the conveyor belt, you would believe that the plane could take off.

Put a toy car on a treadmill...push it forward and try to make it stop by increasing treadmill speed...see what happens...

I must be crazy for actually showing the physics behind this problem...

Oh fvck. Nevermind. I finally figured it out in my head and then realizeed you posted the answer above:
The force of the treadmill acts only on the wheels.
Why the fvck didn't I get that. I guess it didn't help that most people here are posting nonsense... sorry
 
Feb 19, 2001
20,155
23
81
Originally posted by: PurdueRy
Originally posted by: DLeRium
Originally posted by: OvErHeAtInG
Originally posted by: UlricT
WTF guys... the planes wheels are free-rolling. It does NOT drive the plane. The wheels will just spin twice as fast as the plane is moving forward (plane speed + conveyor belt speed)!

OK this is a great example of why seemingly intelligent people actually think the plane would take off. They misread the question and think the plane is actually moving relative to the air.

* If the plane is moving (fast enough) relative to the atmosphere, it will generate lift and take off.
* If the plane is not moving (fast enough) relative to atmosphere, it will not generate lift and take off.

See? Not so complicated. No differential equations, no general relativity, no damn Lorentz transformation. :roll:

The question, as I originally read it on ATOT months ago (maybe year+) stated that the speed of the conveyor would always match the speed of the plane relative to the conveyor. Meaning that the plane won't go anywhere relative to the atmosphere. However, if you wish to read the (very poorly worded) question as allowing for the increased velocity of the plane without a corresponding increase relative to the conveyor belt, you would believe that the plane could take off.

If the conveyor matches the speed of the plane, it does NOT mean the plane won't go anywhere relative to the atmosphere.

How about this? vplane = 100 m/s, vconveyor = -100 m/s. With respect to the ground, both parts are moving, but the plane takes off. Ch-Ching.

Did we misread? Nope. Did you misinterpret the question? Yes. Did you not understand the physics thats going on? Yes.

QED.

Dude, he figured it out in a future post:

LoL I was stuck like 5 pages back because that's when I left my computer and now I just came back =P. My bad!
 

PurdueRy

Lifer
Nov 12, 2004
13,837
4
0
Originally posted by: DLeRium

LoL I was stuck like 5 pages back because that's when I left my computer and now I just came back =P. My bad!

no problem, just didn't want people harping on the guy cause he took the time and figured it out. He shouldn't be derided ;)
 

MrPickins

Diamond Member
May 24, 2003
9,125
792
126
For everyone that still thinks that the conveyor belt can inpart enough force (via the friction in the wheel bearings)to keep the plane stationary, consider THIS scenario. (Yes, I know my MsPaint are 1337 ;) )

Say you spin the conveyor belt backwards at 200mph, the winch should have no problem keeping the airplane stationary, do you agree? Of course assuming the tires are rated for this speed.

If the winch continues applying more force, does it not also stand to reason that the winch could begin to pull the airplane down the conveyor belt, even if you began increasing speed on the conveyor? Remember, wheels on an airplane are freespinning, so the backward force from the convyeor would be relatively small.

If the winch is strong enough, it theoretically could accelerate the airplane to sufficient speed for flight. It just needs to be able to apply enough force.

We can subtitute the airplane's engine for the winch, as both serve the same purpose of applying a force in a forward vector. As has been stated numerous times, the jet (or prop) engine in no way relies on the wheels for thrust, instead it "pulls" on the air much the same way the winch pulls on the rope. Neither the rope nor the air are affected by the conveyor belt.

Now the question is whether or not the airplane's engine can provide the amount of thrust required ot counteract the friction in the wheels, and still accelerate the airplane to takeoff speed.

As small as the friction in the bearings should be, That should be no problem for any planes with engines of an approptiate size for the aircraft.
 

AccruedExpenditure

Diamond Member
May 12, 2001
6,960
7
81
Originally posted by: MrPickins
For everyone that still thinks that the conveyor belt can inpart enough force (via the friction in the wheel bearings)to keep the plane stationary, consider THIS scenario. (Yes, I know my MsPaint are 1337 ;) )

Say you spin the conveyor belt backwards at 200mph, the winch should have no problem keeping the airplane stationary, do you agree? Of course assuming the tires are rated for this speed.

If the winch continues applying more force, does it not also stand to reason that the winch could begin to pull the airplane down the conveyor belt, even if you began increasing speed on the conveyor? Remember, wheels on an airplane are freespinning, so the backward force from the convyeor would be relatively small.

If the winch is strong enough, it theoretically could accelerate the airplane to sufficient speed for flight. It just needs to be able to apply enough force.

We can subtitute the airplane's engine for the winch, as both serve the same purpose of applying a force in a forward vector. As has been stated numerous times, the jet (or prop) engine in no way relies on the wheels for thrust, instead it "pulls" on the air much the same way the winch pulls on the rope. Neither the rope nor the air are affected by the conveyor belt.

Now the question is whether or not the airplane's engine can provide the amount of thrust required ot counteract the friction in the wheels, and still accelerate the airplane to takeoff speed.

As small as the friction in the bearings should be, That should be no problem for any planes with engines of an approptiate size for the aircraft.

You're wrong.
 

jagec

Lifer
Apr 30, 2004
24,442
6
81
Originally posted by: MrPickins
For everyone that still thinks that the conveyor belt can inpart enough force (via the friction in the wheel bearings)to keep the plane stationary, consider THIS scenario. (Yes, I know my MsPaint are 1337 ;) )

Say you spin the conveyor belt backwards at 200mph, the winch should have no problem keeping the airplane stationary, do you agree? Of course assuming the tires are rated for this speed.

The sticky part is that the speed of the conveyor and the acceleration of the conveyor act upon the plane in different ways.
 

MrPickins

Diamond Member
May 24, 2003
9,125
792
126
Originally posted by: AccruedExpenditure
Originally posted by: MrPickins
For everyone that still thinks that the conveyor belt can inpart enough force (via the friction in the wheel bearings)to keep the plane stationary, consider THIS scenario. (Yes, I know my MsPaint are 1337 ;) )

Say you spin the conveyor belt backwards at 200mph, the winch should have no problem keeping the airplane stationary, do you agree? Of course assuming the tires are rated for this speed.

If the winch continues applying more force, does it not also stand to reason that the winch could begin to pull the airplane down the conveyor belt, even if you began increasing speed on the conveyor? Remember, wheels on an airplane are freespinning, so the backward force from the convyeor would be relatively small.

If the winch is strong enough, it theoretically could accelerate the airplane to sufficient speed for flight. It just needs to be able to apply enough force.

We can subtitute the airplane's engine for the winch, as both serve the same purpose of applying a force in a forward vector. As has been stated numerous times, the jet (or prop) engine in no way relies on the wheels for thrust, instead it "pulls" on the air much the same way the winch pulls on the rope. Neither the rope nor the air are affected by the conveyor belt.

Now the question is whether or not the airplane's engine can provide the amount of thrust required ot counteract the friction in the wheels, and still accelerate the airplane to takeoff speed.

As small as the friction in the bearings should be, That should be no problem for any planes with engines of an approptiate size for the aircraft.

You're wrong.


What amazing insight, and such a constructive addition to the conversation! :roll:


Originally posted by: jagec
The sticky part is that the speed of the conveyor and the acceleration of the conveyor act upon the plane in different ways.

The end result of the speed and acceleration of the belt should both be a force pushing backwards, even if the acceleration causes a force that increases on an exponential curve, correct?