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Posers and Puzzles

Posers and Puzzles

  1. 31 Oct '07 01:26
    http://community.discovery.com/eve/f...5321919039/p/1

    Originally Posted by Discovery Channel Press Release
    "MYTHBUSTERS" CONTINUES TO MAKE SCIENCE COOL WITH SEVEN ALL-NEW EPISODES BEGINNING OCTOBER 31...

    ...Airplane Hour
    (Weds., December 12 at 9 PM ET/PT)
    Adam and Jamie find out if either of them can safely land a Boeing 747-400 on a runway in varying weather conditions. Meanwhile, Kari, Tory and Grant risk life and limb to investigate skydiving myths regularly featured in Hollywood action films. Is it possible to catch up with someone in freefall if that person jumps out a plane before you do? Can you really hold a conversation during freefall? And would you survive if you opened your parachute only a few feet off the ground? Finally, Adam and Jamie carefully navigate their way through a myth that has baffled everyone from web bloggers to pilots. If a plane is traveling at takeoff speed on a conveyor belt, and the belt is matching that speed in the opposite direction, can the plane take off? Extensive small-scale testing with a super treadmill and a nearly uncontrollable model airplane don't completely resolve the myth, so our flight cadets supersize the myth with help from a willing pilot and his Ultralight flying machine.


    http://www.redhotpawn.com/board/showthread.php?threadid=54537&page=1

    http://www.redhotpawn.com/board/showthread.php?threadid=55074&page=1

    I still stand on by my original post's The Plane WILL take off.

    Many of you all said that it WONT take off,

    I guess we will see
  2. 31 Oct '07 04:47
    Originally posted by flyUnity
    http://community.discovery.com/eve/f...5321919039/p/1

    [quote]Originally Posted by Discovery Channel Press Release
    "MYTHBUSTERS" CONTINUES TO MAKE SCIENCE COOL WITH SEVEN ALL-NEW EPISODES BEGINNING OCTOBER 31...

    ...Airplane Hour
    (Weds., December 12 at 9 PM ET/PT)
    Adam and Jamie find out if either of them can safely land a Boeing 747-400 on a runway ...[text shortened]... Plane WILL take off.

    Many of you all said that it WONT take off,

    I guess we will see
    I live in Australia so we get these episodes late. Can someone post the result once this episode is screened please...

    Not that it needs an experiment to prove it, the plane will fly.
  3. 31 Oct '07 07:31
    Absolutely every physicist/expert/anyone who looks at the facts concludes that the plane will take off. The only people who argue otherwise are deluded by what they think is a more difficult concept to understand.
  4. 31 Oct '07 08:15
    If, after a question is posted, not the obvious anser arrives, perhaps the question is not so wellformulated.

    This is a matter of communication. Well defined question usually gives well defined answers. If the answer is known from the beginning, perhaps the question shouldn't be posted at all?
  5. Standard member TheMaster37
    Kupikupopo!
    31 Oct '07 08:40
    How on earth would it be able to take off?

    There is no lift from the air around the plane since the air isn't moving with respect to the plane.
  6. 31 Oct '07 08:53
    Originally posted by TheMaster37
    How on earth would it be able to take off?

    There is no lift from the air around the plane since the air isn't moving with respect to the plane.
    Hang your head in shame.

    Actually wait, first read the hundreds of posts on this matter on these forums, then google the problem and find the many good explanations.

    Then hang your head in shame.
  7. 31 Oct '07 11:32
    Think I'll go hang my head in shame too. Can't see how it would take off....

    If a F1 car can create enough downforce to drive upside down at 120 mph, are you saying it could create the downforce upside down on a treadmill ??
  8. Standard member TheMaster37
    Kupikupopo!
    31 Oct '07 11:32 / 1 edit
    Originally posted by Marsan
    Hang your head in shame.

    Actually wait, first read the hundreds of posts on this matter on these forums, then google the problem and find the many good explanations.

    Then hang your head in shame.
    *hangs head in shame*

    Though from what I understand the plane will not remain motionless. It should shoot off the conveyor as the engines are pushing the air, not the ground.
  9. Standard member TheMaster37
    Kupikupopo!
    31 Oct '07 11:37
    Originally posted by Ciaran
    Think I'll go hang my head in shame too. Can't see how it would take off....

    If a F1 car can create enough downforce to drive upside down at 120 mph, are you saying it could create the downforce upside down on a treadmill ??
    F1 cars gain speed pushing themselves forward on the ground.

    Airplanes push themselves forward by air. The wheels are just there to reduce friction with the ground (the engines don't work on the wheels)

    So the car will crash down in a treadmill.
  10. 31 Oct '07 11:55
    "the belt is matching that speed in the opposite direction"

    Does this not mean that how ever much thrust goes through the engines the "belt" will match the speed the wheels are moving irrelevant to what is driving them. A bit like putting you car on a Dyno ??
  11. 31 Oct '07 11:58
    Arggggghhhhhh!
  12. 31 Oct '07 13:34
    "If a plane is traveling at takeoff speed on a conveyor belt...."

    Everyone seems to think that this means the place is travelling at takeoff speed relative to the conveyor belt and hence stationary relative to the ground. It's actually travelling at take off speed relative to the ground, and hence (2 x take off speed) relative to the conveyor belt.

    To be honest, I think the confusion is entirely due to the appalling wording of the original question - you can't blame people for getting the wrong answer if the question's been mis-understood in the first place, they're just not going to get it right. Make it clear that the take off speed is relative to the ground, and everyone's a winner.

    That's was my moment of realisation anyway, it became clear it would take off after that bit was explained to me.
  13. Standard member TheMaster37
    Kupikupopo!
    31 Oct '07 14:58
    The plane will still go forward, no matter how fast the conveyor is running.

    The engines give a force forward on the plane.

    The conveyor does NOT give a force backward on the plane since the wheels are free to rotate as fast as needed.
  14. Standard member uzless
    The So Fist
    31 Oct '07 15:15 / 1 edit
    Originally posted by TheMaster37
    The plane will still go forward, no matter how fast the conveyor is running.

    The engines give a force forward on the plane.

    The conveyor does NOT give a force backward on the plane since the wheels are free to rotate as fast as needed.
    Jebus, talk about confusing language. Look, it's simple.

    The plane is NOT stationary. It is moving forward at the regular take off speed and will therefore of course take off.

    The converyor belt nonsense is there just to add confusion. It's irrelevant. The wheels will just be moving faster than normal.

    End of story.
  15. 31 Oct '07 15:27 / 1 edit
    Originally posted by uzless
    The plane is NOT stationary. It is moving forward at the regular take off speed
    Exactly - why can't the question say that?

    If I said I was running on a treadmill (= conveyor belt) you wouldn't take that to mean I was moving relative to the ground, and hence double "normal" speed against the treadmill. You'd read it as me running at a speed relative to the treadmill and stationery relative to the ground.

    The logical/normal way to read "moving at take off speed on a conveyor belt" is to assume that it is stationery to the air/ground.