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Post by Mike B on Feb 21, 2008 21:42:44 GMT 1
but if somebody standing beside you put his hand on your back and gave you an almighty shove, you would shoot forward....and that is how the thrust for the engines work, they shove the aircraft forward throught he air, regardless of what is happening to the treadmill. Would normally agree, but if you read the original statement, the forward shove would be counteracted by the treadmills detection system speeding up to compensate, thereby keeping you in the same relative position as the guy standing alongside.
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Post by Mark on Feb 21, 2008 23:57:41 GMT 1
Well put Eric. If anybody still wants to disagree we can put them on the tread mill and demonstrate with a almighty well placed foot
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Post by nemesis on Feb 22, 2008 1:24:37 GMT 1
Are we STILL on about this, lol? Mike has it spot on again. I ain't saying any more than that
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Post by swanrail on Feb 22, 2008 11:25:44 GMT 1
Except Mike you have overlooked inertia, by the time that the belt realised there was a change in motion, it would be too late!!!! (which I think is what Mark is saying). ;D ;D ;D
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Post by nemesis on Feb 22, 2008 13:33:48 GMT 1
Yes but that wasn't the question. PPl are trying to apply extra criterior to the original question. We're answering the question as asked and it specifies that this "conveyor belt" is able to match exactly the motion of the aircraft. If you stay within the specifics of the question, that aircraft won't take off.
This is becoming a saga as big as "War and Peace", lol.
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Post by afkmatrix on Feb 22, 2008 13:38:16 GMT 1
Yeah what have I started!!! Just feel happy that this is raging on across the internet on many forums lol. Oh and I do belive to solve this we need to appropriate a plane and a large factory conveyer belt and make a day of wizzing planes along a conveyer belt rofl
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Post by Mark on Feb 22, 2008 14:46:13 GMT 1
And where in the question does it say the plane has to stay still ? It sayt he belt moves backwards at the same speed the plane moves forwards. It doesn't say that the plane stays still.
Now, where's me hobnails gone.......
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Post by nm on Feb 22, 2008 14:55:39 GMT 1
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Post by eric on Feb 22, 2008 15:33:42 GMT 1
In truth, it's a bit of a trick question, because the aircraft is not reliant on the wheel speed to dictate its AIR speed, the wheels can go around as fast as they like, and the aircraft will still be thrust forward through the air by its engines until it reaches takeoff velocity.
The belt will only slow the aircraft by the increase in friction caused by the faster wheel speed, and that is nowhere near enough friction to prevent the aircraft phisycally accelerating.
Oops, sorry.....I promised not to mention it again....!
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Post by nemesis on Feb 22, 2008 20:57:27 GMT 1
Quote from the original question...
The question doesn't once mention friction, speed of the wheels, air speed or magic moonbeams. It clearly states the belt exactly matches the "speed" of the aircraft but in the opposite direction. This being the case, that aircraft is stationary in relation to the ground.
This is a great game of verbal pingpong, lol.
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Post by jim on Feb 22, 2008 22:27:45 GMT 1
aerodynamics need forward motion, for a wing to be effective it must have airflow, if the plane is on a rolling road (not going forward ) there will be no lift to the wings. no matter how hard you push the engines if the plane cannot encounter wind resistance then the wings are useless.
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Post by jim on Feb 22, 2008 22:37:46 GMT 1
ive run six miles today on a treadmill got no-where, fekk these rolling roads, if i had run on the road i might have found a good pub
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Post by jim on Feb 22, 2008 22:44:41 GMT 1
(thinks) but then a taxi back (hmmm)
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Post by nm on Feb 22, 2008 22:53:01 GMT 1
Of course the plane takes off! Unless the conveyor belt is stationary.
The plane moves forward at the same speed the belt moves backwards. So their speed relative to each other is twice the speed of each (otherwise the plane is not moving forward.)
Say the belt moves backwards at 200 mph. Speed of plane over the "ground" is 400 mph. Forward speed of aircraft is 200 mph. If that's not fast enough, double all the figures.
NM
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Post by jim on Feb 22, 2008 23:03:46 GMT 1
errmmm just checked the original question, you stated the plane is on a runway, did not state the plane is on the conveyer. so my answer is yes the plane can take off cause it it aint on the conveyer
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