...I found it presented at http://boards.straightdope.com/sdmb/showthread.php?t=34 8452:The emerging consensus (at least as far down as I read) seems to be that the plane wouldn't take off, because it wouldn't have enough airspeed to generate lift. But that argument seems to take it as a given that the conveyer belt is preventing the plane from moving forward, which to me seems silly. As the quote above says, the thrust would be provided by the engines, which are pushing against the air, not the conveyer belt. I liked the comment that suggested picturing a prop plane instead of a jet, since the props pulling the plane through the air is somehow more intuitive than the jets pushing it. (This is all assuming that friction would not be a factor, and I don't think this puzzle is really about friction.)
“Imagine a plane is sitting on a massive conveyor belt, as wide and as long as a runway. The conveyer belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?
“I say no, because the plane will not move relative the the ground and air, and thus, very little air will flow over the wings. However, other people are convinced that since the wheels of a plane are free spinning, and not powered by the engines, and the engines provide thrust against the air, that somehow that makes a difference and air will flow over the wing.”
The guy behind me at the airport told his buddy that, in fact, the plane WOULD take off, and his buddy seemed to agree. Do we have any physicists in the audience?
Anyone else have any thoughts on this? Can anyone explain how the conveyer belt would prevent a plane from moving forward fast enough to generate lift?