Airplane on a Conveyor Belt...

[john9001]

Originally posted by AKIron
It takes energy from the plane's engine to keep the wheel from rolling backwards with the belt.  

the tire can not roll backwards because the belt can only match the wheel speed, and where does the energy from the belt go?


the energy required to spin the wheels is greatly over estimated.

[AKIron]

It occurred to me that you are probably thinking of a fixed speed belt rather than an accelerating belt Chairboy. Which will apply more force to the wheel (which must be countered by the plane's engine), a belt that accelerates from 0-100 mph in 1 minute or a belt that accelerates from 0-10,000 mph in 1 minute?

[AKIron]

Originally posted by john9001
the tire can not roll backwards because the belt can only match the wheel speed, and where does the energy from the belt go?


the energy required to spin the wheels is greatly over estimated.

Before we go there we have to establish which speed the belt must match. Are we talking about the belt matching the wheels axis (and therefore the plane's speed relative to a tree sitting next to the belt) or the surface of the tire?

[AKIron]

Once we agree on the what speed the belt must match we must then agree on how quick the belt is allowed to respond to changes in the wheel and how fast the belt is allowed to go.

[Chairboy]

Originally posted by AKIron
It occurred to me that you are probably thinking of a fixed speed belt rather than an accelerating belt Chairboy. Which will apply more force to the wheel (which must be countered by the plane's engine), a belt that accelerates from 0-100 mph in 1 minute or a belt that accelerates from 0-10,000 mph in 1 minute?

Akiron, why are you changing the problem?  Now you're talking about something called 'force to the wheel' as if it means anything to this conversation.  Have you moved on from the treadmill 'problem' to something else?

[AKIron]

Originally posted by Chairboy
Akiron, why are you changing the problem?  Now you're talking about something called 'force to the wheel' as if it means anything to this conversation.

Force to the wheel is relevant and is the focus of Eskimo's question about Bob, Al, and whatever his name is.

[AKIron]

More importantly though Chairboy, you just demonstrated the nature of the problem, that being that we don't all agree on what the problem actually is. For that matter, I think many of us don't even understand or agree that we don't agree on what the problem is. Kinda like RL.

[Yknurd]

I think we can safely make the following assumptions:

AKIron will unconditionally continue to think that Chairboy is wrong.

Chairboy will unconditionally continue to think that AKIron is wrong.

A lot of homosexual sexual tension has been building.

[AKIron]

I'm thinking that plane would roll a lot better with Yknurd under the wheels.

[AKIron]

Eskimo made some excellent videos to illustrate the forces involved. His story about Bill, Ted, and Alice also illustrates the problem well though it may be a tad hard to follow. As has been repeated here ad nauseam, there are basically two scenarios. The first was just demonstrated on the who cares channel. The second is much more interesting as there are a lot of variables. It is this second to which all my replies address.

[sluggish]

Originally posted by eskimo2
As it applies to the question where the conveyor exactly matches the plane’s speed; the difference is so slight that it wouldn’t hardly matter.  The plane will take off almost exactly within the same distance.

The original AH BBS thread question said: “the conveyor exactly matches the plane’s wheel’s speed”.  This changes everything.  In this instance, the conveyor must assume an accelerate rate that loads as much rotational energy into the ever increasing wheel speed to match the thrust of the engine/prop.

Your theory relies on unfairly applying the laws of physics to the wheel while totally disregarding them for the belt.  If the belt can defy the laws of physics and instantly ramp up to infinitey, those same non-laws must also apply to the wheels.

The plane flies.

[AKIron]

Originally posted by sluggish
Your theory relies on unfairly applying the laws of physics to the wheel while totally disregarding them for the belt.  If the belt can defy the laws of physics and instantly ramp up to infinitey, those same non-laws must also apply to the wheels.

The plane flies.

Uh, if that belt can ramp up to infinity that plane most definitely won't be flying, at least in this universe.



Seriously though Sluggish, set some parameters for the belt. The math can be done to determine if the plane can fly.

[Yknurd]

Originally posted by AKIron
I'm thinking that plane would roll a lot better with Yknurd under the wheels.

LOL

[sluggish]

Originally posted by AKIron
Uh, if that belt can ramp up to infinity that plane most definitely won't be flying, at least in this universe.



Seriously though Sluggish, set some parameters for the belt. The math can be done to determine if the plane can fly.

Why do I have to set parameters for the belt?  In order for the belt to instanly compensate for the movement of the wheel, there can be no parameters.  In order for this to be fair, the wheel must also follow the same non-parameters.

the plane flies.

[Chairboy]

Sluggish, the problem here, it seems, is that some folks (unsatisfied perhaps with the result) are now trying to re-define the problem until they find a way that makes it not fly.  Constantly repasting the 'tundra tires' puzzle is one method, another has to do with creating mathematical abstractions that attempt to violate the laws of physics by "just going faster" and pretty soon, people are throwing around concepts like 'infinite speed'.

Science is a harsh mistress.  u*N is the law of the land, and no amount of mental bananay is going to get this girl pregnant.