Cal Weldon said:
Yes if you take the reference point as the center of the wheel then unless the belt or wheel is slipping then the speed of the belt matches the speed of the rotation of the wheel 🙂 regardless of what speed the plane is moving in a forward direction 🙂
Tony.
maxro said:
Sorry Max, my fault.
Yes I think if you add the air speed from the engines, which has created the wheel speed in the first place to the counteractive belt you get wheel speed = 2X air speed
Pray tell?
ok , then, u should explain that to me one more time 🙂eVITAERC said:
when i say no friction , i dont mean that there's no wheel / ground friction , of course there is a static friction between them .
if there werent static friction between them the wheel would not even spin ...
when i say no friction in theory , i mean wheel bearing -kinetic friction .thats why , in theory the wheels and the belt will spin at infinate speed , but it wont stop the plane from taking off...
think i'm wrong? plz explain yourself then 🙂
Cal Weldon said:
"The conveyer belt is designed to exactly match the speed of the wheels at any given time, moving in the opposite direction of rotation."
The wheel speed can not exceed the belt speed.
At first, I too, thought: no problem, wheels spin fast, so what? plane takes off. (Check back about 30 pages ago.)
But Wintermute and RDFan set me straight.
Soon, you too, will be assimilated.
Max
Max you are correct, and so is Cal the question (and how you interpret it) is the problem!!
If you consider the ACTUAL physics then the scenario as I initially interpreted, and you have interpreted is not in reality possible, however if you ignore the physics of jet propultion and interpret the question the way you have and I originally did, then the answer is the plane can't move forward so cant take off.
In the end the question is flawed and it depends on the interpretation 🙂
though I guess if you wanted to have a physically correct answer that doesn't break the rules of the question there have been a couple that work, but you have to make the point of reference not be the "stationary" earth.
Tony.
If you consider the ACTUAL physics then the scenario as I initially interpreted, and you have interpreted is not in reality possible, however if you ignore the physics of jet propultion and interpret the question the way you have and I originally did, then the answer is the plane can't move forward so cant take off.
In the end the question is flawed and it depends on the interpretation 🙂
though I guess if you wanted to have a physically correct answer that doesn't break the rules of the question there have been a couple that work, but you have to make the point of reference not be the "stationary" earth.
Tony.
sss said:
If the belt is spinning at infinite speed, then the plane's wheels must spin at infinity+take off speed. Therefore the speeds will not match.
Sure, I guess a hundred miles an hour is just rounding error when it comes to infinity.
So, given a certain amount of error in the system, the plane would fly.
max
wintermute said:
Well, there is no question that this is a physically impossible situation.
However, the point of reference must be the air/ earth or the plane itself, for the plane has to move through the air to fly.
Max
I was just having my dessert and halfway through my blood curdled. My palms are sweaty and I'm shaking as I type.
If the plane has moved across the belt from the start to the finish, the wheels have had to turn faster than the belt.
Oh #@&%*$!?"+& and double *&^"~!@#$&*@$#%^
I hate this %$@#!*&% ing thread
That means it can't takeoff
Ah triple $%#@&*!
Max where are you?
If the plane has moved across the belt from the start to the finish, the wheels have had to turn faster than the belt.
Oh #@&%*$!?"+& and double *&^"~!@#$&*@$#%^
I hate this %$@#!*&% ing thread
That means it can't takeoff
Ah triple $%#@&*!
Max where are you?
maxro said:
ahhh but does it 😉 the point of reference is just an observation point, the act of observing doesn't change whats happening (or does it!!! oh no what have I said, we don't want to bring quantum physics into the discussion 😉 )
all we are observing is the speed of the belt and the wheel, the question doesn't mention anything about the air (apart from there being no wind, which is IMO a red herring to reinforce the view that the plane remains stationary)... so I think that if I answered the question stating my assumtions and point of reference and said that the plane does take of no examiner could mark me wrong 🙂
Tony.
LMAO at Cal 😉 perhaps you should read this that I posted way back ---> http://www.diyaudio.com/forums/showthread.php?postid=776846#post776846
now I have since thought of other ways where the plane can take off and not break the rules (thanks to Dan and Chris) with creative use of points of reference, but it might help you feel better again 😉
edit: but the main point with that post was that the interpretation of speed and whether it is angular or linear motion (ie the perifery of the wheel or the center of the wheel) which changes the whole ball game.
Tony.
now I have since thought of other ways where the plane can take off and not break the rules (thanks to Dan and Chris) with creative use of points of reference, but it might help you feel better again 😉
edit: but the main point with that post was that the interpretation of speed and whether it is angular or linear motion (ie the perifery of the wheel or the center of the wheel) which changes the whole ball game.
Tony.
I think the motion would be considered the contact point of wheel and belt (is that angular?) or the it wouldn't have the same relevance.
But what the @%$#*& do I know I've changed parties twice now.
Oh man, time for a
I don't believe this.
But what the @%$#*& do I know I've changed parties twice now.
Oh man, time for a
I don't believe this.
hehehe just join me and sit on the fence Cal it is much easier on the brain 😉 yeah angular velocity isn't the best term, lostcause put it better later on by saying the surface speed of the wheel matches the surface speed of the belt.... which when you think of it is always true regardless of forward or reverse motion (relative to the earth) provided there is no wheel slip, but this requires taking the reference point as being the center of the wheel, as clearly the rotational speed of the belt and the rotational speed of the wheel can never be equal unless their diameter is the same 🙂 which it can't possibly be because the belt is the length of the runway X 2 + a bit 😉
Hmmmmm now I'm wondering whether it matters whether the reference point is the wheel or not...... as it is the relative speed between the two objects that matters, and the earth has nothing to do with it.... no time to go glue in some nuts to my speaker baffles.... I must not think brain not happy....
hope that didn't confuse you more 🙂
Tony.
Hmmmmm now I'm wondering whether it matters whether the reference point is the wheel or not...... as it is the relative speed between the two objects that matters, and the earth has nothing to do with it.... no time to go glue in some nuts to my speaker baffles.... I must not think brain not happy....
hope that didn't confuse you more 🙂
Tony.
pinkmouse said:
On behalf of eVITAERC, maxro and myself (and the two hot chicks) - Welcome aboard Cal!
Pinacoladas 24/7 on the prominade deck.
An externally hosted image should be here but it was not working when we last tested it.
RDFan said:
Very funny RDFan.
Now if we could just get this dang cruise ship to leave harbour against the speed-matching current.
Max
wintermute said:
Hey Tony, I beat you by 9 posts
RDFan said:
And actually, Mr. Evil says the same in post #5.
RDFan said:
actually I said this way back in post 88 (which was where the thread was up to when I first posted 😉 )
na na ni na na 😉
but back then I also said some complete nonsense too to back up my claims 😉
Tony.
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