hmmm.... physics question for you guys....

[StukaJU87]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
(Also notice on helicopters they have their blades to provide upward momentum and lift but they also have other engines (mostly jet) to provide forward propulsion)

[/ QUOTE ] And what about the early helicopters and newer non jet powered helicopters? Hmmm.... wonder how they flew. [img]/images/graemlins/laugh.gif[/img]

[GodOfRhythm]

Re: hmmm.... physics question for you guys....

It's not easier, I find the non-positive sciences to be just as hard, just because most of them are non-mathematic in nature doesn't make them any less hard or inferior.

I chose law because it's about the ONLY thing I can study at university without any math (except for a bit of economy).

[Endrik]

Re: hmmm.... physics question for you guys....

hmmm, yes and no...studying eastern languages is harder than physics, studing history is as easy/hard as physics but the social and religion shit is too easy, you only need your own opinion there [img]/images/graemlins/laugh.gif[/img]

[Bert]

Re: hmmm.... physics question for you guys....

I'm with Zeeg, VitG and company: the only affect of the belt is to increase friction on the wheels, which is negligible compared to the forward engine thrust. You'd have to turn a wheel pretty damn fast to generate enough friction to counteract a jet engine. Note that the plane's wheels simply turn twice as fast as usual, so while that's twice as much friction as before, two times almost nothing is still almost nothing.

[rjohnstone]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
[ QUOTE ]
(Also notice on helicopters they have their blades to provide upward momentum and lift but they also have other engines (mostly jet) to provide forward propulsion)

[/ QUOTE ] And what about the early helicopters and newer non jet powered helicopters? Hmmm.... wonder how they flew. [img]/images/graemlins/laugh.gif[/img]

[/ QUOTE ]
Traditional, non-turbine powered helicopters tilt/pitch the collector forward to provide forward thrust.

[monk]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
Phyisics are easy, just plain and simple logic.

[/ QUOTE ]

Hehe...upper level physics (when you involve relativity, quantum phenomena and things as turbulence and chaos etc) is NOT easy, and the involved logic is way more discursive. [img]/images/graemlins/smile.gif[/img]

I believe that the plane will take off, with the following reasoning:

Without the conveyor-belt, the plane will take off just as normal. The jet engine works by throwing mass (air) backwards. Newton says that this will create a force acting on the engine in the opposite direction. This force is what causes the plane to accelerate, because the force is greater than the forces in the other direction (such as drag, or friction from the wheels).

Adding the conveyor belt will not change this. The only thing that will happen is that the wheels will turn faster (twice the amount of revolutions/time). Of course, this will cause more friction, but the thrust force generated by the engine will still be great enough to cause the acceleration.

It does not matter if the wheels are spinning or not (if we assume that the friction caused by the wheels are no way near as large as the thrust force)

[sithgt6]

Re: hmmm.... physics question for you guys....

No variables have been implied or allowed.

If a plane moves forward and the runway counteracts that movement there will be NO forward motion, there will be NO lift - therefore, the plane CANNOT fly or do a runup to fly.

It will sit in one place, engines running, wheels turning and that's it.

D>

[Endrik]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
[ QUOTE ]
Phyisics are easy, just plain and simple logic.

[/ QUOTE ]Hehe...upper level physics (when you involve relativity, quantum phenomena and things as turbulence and chaos etc) is NOT easy, and the involved logic is way more discursive. [img]/images/graemlins/smile.gif[/img]


[/ QUOTE ]

It is to me, I've been on those lectures in the University [img]/images/graemlins/wink.gif[/img]

anyway, the plane can not take off, guys, you are forgetting the most improtant thing, the wings, you are talkin' about the wheels, the enginges etc. this is crap. The wings is the key word. Think for a second.
I know something about planes too, I even planned to go to the pilots school a couple of years ago but there was this math things so I said fuck it [img]/images/graemlins/laugh.gif[/img]

[monk]

Re: hmmm.... physics question for you guys....

Yeah, sure it is...

This has nothing with planes to do, actually. The major question is if the plane will move relative to the air, or not.

The plane could take off without wheels, as long as the force generated by the engine is larger than the frictional force caused by the ground (belt) on the plane. Wheels help keeping the friction down to a minimum.

[Bert]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
If a plane moves forward and the runway counteracts that movement there will be NO forward motion...

[/ QUOTE ]

True, BUT, the point is there is nothing that is counteracting the plane's forward movement. The problem statement merely says the conveyer belt turns at a speed that is equal to that of the plane's forward motion, only in reverse. The only force counteracting the plane's forward motion is therefore the friction induced by the spinning wheels, which is negligible even given the spinning belt.

No advanced physics here my friends, it's basic classical/Newtonian mechanics.

[Top Jimmy B]

Re: hmmm.... physics question for you guys....

Newton was a pussy. Who spends their free time thinking up this shit and making it law? I didn't vote for this crap.

[hippietim]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
I know something about planes too, I even planned to go to the pilots school a couple of years ago but there was this math things so I said fuck it [img]/images/graemlins/laugh.gif[/img]

[/ QUOTE ]

You were *thinking* about going to pilots school. Why didn't you say so before? I guess I'll go tell my buddy that *is* a pilot that he doesn't know as much about flying as you. After all, he only finished pilots school.

[toejam]

Re: hmmm.... physics question for you guys....

[ QUOTE ]
Newton was a pussy. Who spends their free time thinking up this shit and making it law? I didn't vote for this crap.

[/ QUOTE ]
[img]/images/graemlins/stupid.gif[/img] I'm more inclined to vote for Murphy's Law. [img]/images/graemlins/laugh.gif[/img]

[Zerberus]

Re: hmmm.... physics question for you guys....

Will Fly because the treadmill causes no notable drag.

This question is actually when you think about itkind of a a "rehash" of the age old "downwind Turn" story, where it was long debated that a plane turning into downwind would fall from the sky (stall)... which is bs, becasue it´s airspeed has been measured relative to that exact same wind the whole time.....

The question is intentionally so worded as to be vage and unclear...

Fact is: the engine will produce thrust.

This thrust would normally be translated to ground speed with the plane on the ground, but that is, for the question at hand, semi-irrelevant, as with no winds ground speed = air speed.

Every other pilot here should agree w/ me that ground speed and air speed are not directly related.... I too have done 40 knots but been moving literally backwards over ground...

And that´s the point... the ground is irrelevant... the airplane would eventually gain enough airspeed to take off, as a conveyor spinning against the freewheeling gear would cause more friction on the wheels, but would not cause any in this scenario notable amount of Drag...But DRAG is what we need to counteract engine thrust (which we need to produce lift).

It may need a few feet more, but it will take off.

BTW: the experiment w/ the balsa plane is just fine, as the thrust:weight ratio of the plane is 1. undefined and 2. Irrelevant [img]/images/graemlins/wink.gif[/img]

[RobRR]

...

Yet more prime examples of why college is a waste of time. [img]/images/graemlins/laugh.gif[/img] I love when people come on preaching about their college thinking they know the answer, when in reality they dont. They think just because they went to college everythinig they know is right, and fail to reason with logic.

The plane will fly, theres nothing holding it back. If you want to argue the point, go back and read my old posts first.