Quote:
Originally Posted by MediaCenterJunkie
Heres the original quote
"Imagine a 747 is sitting on a conveyor belt, as wide and long as a runway. The conveyor belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?"
All it says is exactly match the speed of the wheels. It doesn't say anything about velocity or what kind of speed?
I know that sounded reeruned, but IMO the wheels have 2 different speeds.
The speed in which they are traveling in a straight line, forward, connected to the plane, and the speed in which they are spinning.
So which speed are we talking about here?
|
The correct problem has the plane sitting on a free-spinning treadmill that will absorb all the energy the wheels impart to it.
That original quote by
MagicHef is more or less the way Mythbusters stated the problem.
It's not the correct problem. Read the objection here:
Troy Allen • Jan 30 2008 • 10:53PM
I am completely disappointed at Mythbusters handling of this experiment. The science they used and the “explanations” were both completely flawed. The original myth, and ALL of the discussion, centered around one central conceit: The plane would have NO FORWARD MOTION RELATIVE TO THE GROUND because of the conveyor belt matching the speed of the plane. NOT the “speed of the WHEELS of the plane” or any other contrived version.
Of course the plane is going to take off if it has enough forward motion RELATIVE TO THE GROUND to create the Bernoulli effect required to lift the wing because of the airflow over the wing.
I really expected more “science” from MythBusters. They almost explained it properly with the “model car example”. I guess it was the original Myth that was flawed, or my understanding of the Myth. I guess in their mind the myth is that no plane on a conveyor belt can take off if the “speeds are matching in opposite directions”. That is far too simplistic to make a determination, so it is flawed from the get-go.
Those of us who claimed the plane would not take off without forward motion relative to the ground due to the laws of physics are still correct. The planes both had significant forward motion relative to the ground. I just hope everyone involved in the debate understands these distinctions, otherwise this will just dumb down the TV watching public a bit more. It sure was fun though!