Airplane on a Conveyor conundrum

[Slugsie]

well why didnt you make yourself clear from the start.
and since you didnt, it leaves more questions open.

Because I thought that the question was stated clearly enough, and I didn't think that anyone would try to argue that something that was moving wouldn't be moving funnily enough.

then if this is the case, then the plane would not take off because of the reverse force acting on it from the conveyor

There is NO FORCE acting on it. Why can't you understand that? I'm sorry, but you obviously lack a basic understanding of physics and the laws of motion and force. Until you do understand them you won't ever get this, so discussing it becomes pointless.

[dieselboy]

?????????

At the risk of getting sensible in the thread,

The trick part of the question is right at the beginning of the thread, the conveyer belt needs run backwards, try to move the plane backwards, to prove it dosn't matter.

If the plane gained speed through air to generate lift by powering its wheels like a car, then its easy to make the go nowhere by running the belt backwards at the same speed the wheels are running forwards.

But because its getting thrust, against air, from its engines, its negates any holding back effect of the conveyer belt can give on its wheels. In theroy drag on the wheel bearings and weight of the plane on the wheels gives the belt some help, like putting the brakes on would slow the plane down. but it could never practailly be enough to stop normal plane engines pushing the normal plane forwards on normal plane wheels, wether its on a backwards running belt or not, on this planet.

see thats the thing, this isnt a perfect world, and you dont get perfect conditions enough that would prevent the plane from taking off.
but if you did get all the conditions 100%, with the belt and plane speed being measured from the ground, then the reverse force on the wheels will match that of the thrust and stop the plane moving.

this is because if the plane produces full thrust 600mph terminal forward speed, then this means that the plane will only go 600mph forwards. if there is a reverse force on the plane through the wheels of the same, then its not going anywhere.

who isnt being sensible? im making valid points here!
when are you going to open 4x4 toys back up? my truck keeps asking when am i taking it to tonys to get lifted :/

[Sancho]

I didn't think that anyone would try to argue that something that was moving wouldn't be moving funnily enough.

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[Antshiel]

The plane will take off!!!!

A Planes power comes from thrust direct from the engine, not to the wheels, so no matter how the conveyor acted the thrust will power the plane forwards at the same speed that it would if it were on the ground. The conveyor has no bearing on the equation what so ever.

[dieselboy]

There is NO FORCE acting on it. Why can't you understand that? I'm sorry, but you obviously lack a basic understanding of physics and the laws of motion and force. Until you do understand them you won't ever get this, so discussing it becomes pointless.

well obviously not.
you cant understand how something that is moving, isnt really moving at all.

the thing is, i do get it, and for there to be a correct answer, you need to be specific in your question.
and until this happens, there will always be two arguements.

[TonyN]

im making valid points here!

hmmmm.

when are you going to open 4x4 toys back up? my truck keeps asking when am i taking it to tonys to get lifted :/

Not this year! I'll PM you later.

[Slugsie]

thing is, there is no facts. there is only two outcomes here, and each one a different result.

fact 1, if the conveyor provides a force, then the plane must match that force plus more to start accelerating.

fact 2, if object 'A' (plane) moves away from another object 'B' (ground or conveyor) at a given speed, then object B is also moving away from object A at the same speed.

fact 1, the conveyor cannot provide any additional force on the plane that isn't already provided by a normal static runway.

fact 2, the conveyor isn't trying to move away from the plane, simply run at the same speed. It does that by ACTUALLY ACTIVELY moving. You are being deliberately obstreperous by continuing to argue otherwise.

[MattF]

Most people here don't seem to be.

[TonyN]

....obstreperous ...

Wow!

[dieselboy]

The plane will take off!!!!

A Planes power comes from thrust direct from the engine, not to the wheels, so no matter how the conveyor acted the thrust will power the plane forwards at the same speed that it would if it were on the ground. The conveyor has no bearing on the equation what so ever.

the conveyor does have a bearing on the equasion because, if say for example, the conveyor has got the plane to 10mph backwards, and then you switch on the engines, the plane will then have to get its speed from minus 10 to plus 10mph.
there will be a point where the thrust produced will hold it stationary with the fixed ground point.
then more thrust will be needed to get it to 10mph, and even more thrust to get it passed this.

are you saying that if the conveyor has got the plane going backwards at 10mph, and the minute you switch on the engine the plane is going to shoot forward and jump from -10 to 10mph instantaneously?

[Antshiel]

Now you're just being piccy!!

[Slugsie]

the thing is, i do get it, and for there to be a correct answer, you need to be specific in your question.
and until this happens, there will always be two arguements.

Well, I'll remember in future to write a full 100 page spec beforehand because that is obviously the only way for a minority of people to work.

[Slugsie]

Wow!

Thankyou.

[dieselboy]

fact 1, the conveyor cannot provide any additional force on the plane that isn't already provided by a normal static runway.

wrong, yes it can, or else there would be no need for bigger or more engines on any new planes!

fact 2, the conveyor isn't trying to move away from the plane, simply run at the same speed. It does that by ACTUALLY ACTIVELY moving. You are being deliberately obstreperous by continuing to argue otherwise.

this is a contradiction. if the conveyor is running at the same speed as the plane but in reverse, then it is in fact moving away from the plane.
if the conveyor is stationary and the plane is moving, then also the conveyor is moving away from the plane.
if the plane is stationary, and the conveyor is moving then also the conveyor and the plane are moving away from each other

thank you for giving me a word to look up

[Slugsie]

the conveyor does have a bearing on the equasion because, if say for example, the conveyor has got the plane to 10mph backwards, and then you switch on the engines, the plane will then have to get its speed from minus 10 to plus 10mph.
there will be a point where the thrust produced will hold it stationary with the fixed ground point.
then more thrust will be needed to get it to 10mph, and even more thrust to get it passed this.

are you saying that if the conveyor has got the plane going backwards at 10mph, and the minute you switch on the engine the plane is going to shoot forward and jump from -10 to 10mph instantaneously?

Nope, but it will do what it normally does when accelerating to 20mph with a 10mph tailwind. I.e., it'll just get on and do it. Easily.