Physics question/riddle. This is a good one, read it.

Discussion in 'Chit-Chat' started by Arya Ebrahimi, Nov 30, 2005.

?

Will the plane take off?

  1. yes

    37.2%
  2. no

    58.8%
  3. who gives a rats a$$, I'm on the second step of 6-4-6, leave me alone!

    4.1%
Thread Status:
Not open for further replies.
  1. Arya Ebrahimi

    Arya Ebrahimi SILVER Star

    Joined:
    Dec 2, 2003
    Messages:
    3,235
    Location:
    Rockville, MD
    a plane is standing on a movable runway( something like a conveyor).as the plane moves the conveyor moves but in the opposite direction.the conveyor has a system that tracks the speed of the plane and matches it exactly in the opposite direction.

    the question is

    will the plane take off or not?

    Well? Will it?
     
  2. srafj40

    srafj40

    Joined:
    Jun 2, 2003
    Messages:
    153
    Location:
    Sahuarita, Az.
    Into the wind? Or down wind? What is the wind speed on this specific day?
     
  3. Arya Ebrahimi

    Arya Ebrahimi SILVER Star

    Joined:
    Dec 2, 2003
    Messages:
    3,235
    Location:
    Rockville, MD
    No wind, it's a calm day.
     
  4. rusty_tlc

    rusty_tlc Dain Bramaged Member

    Joined:
    Jun 23, 2005
    Messages:
    11,702
    Location:
    Reno, NV
    The wing depends on air speed for lift, ground speed is meaningless.
     
  5. LoveTractor

    LoveTractor

    Joined:
    Mar 30, 2005
    Messages:
    470
    Location:
    Mt. Pleasant, SC
    ditto

    EDITTED 4/6/07 TO HELP THOSE JUST STARTING TO READ THIS THREAD
    THE PLANE FLIES!


    The reason I do this is because many here(including myself) are turning into broken records trying to convince newbs just starting to wrap their squash around the idea that the plane does indeed fly. This thread gets brought up every few months with someone trying to make an argument that the plane does not take off. This is an attempt to nip it in the bud early. If you STILL feel you have an argument that the plane does not fly, have at it...but it's the same wrong argument over and over again.:rolleyes: And it's wrong.;p I too once thought the plane did not fly, but finally saw the light. The plane flies. Period.


    The evolution of my proof:
    A physics force diagram showing the forces involved in the problem:
    plane-diagram2.JPG
     
    Last edited: Apr 6, 2007
  6. Arya Ebrahimi

    Arya Ebrahimi SILVER Star

    Joined:
    Dec 2, 2003
    Messages:
    3,235
    Location:
    Rockville, MD
    FYI, I'm in agreement that it will take off, but apparently this question has spawned 500+ reply posts on other forums :D

    Oh, and for those of you voting no, I wanna hear your reasoning!
     
  7. srafj40

    srafj40

    Joined:
    Jun 2, 2003
    Messages:
    153
    Location:
    Sahuarita, Az.
    Treating it as a linear thinking problem.

    Maybe, just maybe, it was in the gulf coast region as winds picked up to a Cat. 4 or so. :D

    Then again, I am not all that smart.
     
  8. expat

    expat

    Joined:
    Feb 24, 2005
    Messages:
    304
    Location:
    Sunshine Coast
    If the plane is a jet, there is no apparent wind, therefore no lift... If the plane is a prop job, there may be some wind blown across the wings generating some lift, but not likely enough to take off. My opinion...

    Now, if you had a Landcruiser on the same runway, and you stuck your hand out the window, you wouldn't feel anything, as long as there is no frictional wind dragged along the same runway.
     
  9. Lashcat

    Lashcat

    Joined:
    Apr 14, 2004
    Messages:
    127
    Location:
    North Pole, Alaska
    Yes it will take off. Planes gain lift from air speed not ground speed. The prop would still move the plane forward due to the thrust produced by the prop. The speed of the convayor would only make the wheels thurn faster. If this were to be a real life situation i would hate to be the pilot tring it due to the fact of trying to control the plane until it gained enough speed to gian flight. Too much brake on either pedal would end up in a bad situation.
     
  10. baxter650

    baxter650

    Joined:
    Aug 8, 2005
    Messages:
    1,565
    Location:
    Grand Forks B.C.
    Yes it will, if the plane is going say 200 knots forward the belt will be going 200knots backward. The plane still has forward speed and will take off, the wheels will be going like hell at 400 knots though.
     
  11. Hawke

    Hawke

    Joined:
    Sep 23, 2005
    Messages:
    150
    No go. Plane stationary.
     
  12. Red Herring

    Red Herring

    Joined:
    Feb 28, 2005
    Messages:
    779
    Location:
    Victopia BC
    I think if the conveyor belt is preventing any forward motion of the plane by keeping its relative ground speed at 0, then no lift off will occur. Regardless of thrust applied, if the conveyor belt is matching the speed of the plane in the opposite direction, the plane could not generate speed or thus lift, regardless of how much air was passing through the engines. Ground speed is needed for initial take off.
     
  13. srafj40

    srafj40

    Joined:
    Jun 2, 2003
    Messages:
    153
    Location:
    Sahuarita, Az.

    Sorry but last time I checked a planes engine does not drive the wheels. :confused:
     
  14. LoveTractor

    LoveTractor

    Joined:
    Mar 30, 2005
    Messages:
    470
    Location:
    Mt. Pleasant, SC
    In order for flight to occur, enough wind must hit the front of the wing so that lift occurs under the wing and therefore causing flight. If the plane is on a conveyor belt that is moving backwards and only the wheels are moving, there is no wind on the front of the wing at all to cause lift. Therefore no flight.

    What did I win?

    Crap I'm a slow typer.
     
  15. srafj40

    srafj40

    Joined:
    Jun 2, 2003
    Messages:
    153
    Location:
    Sahuarita, Az.

    What he said.
     
  16. MoJ

    MoJ Moderator

    Joined:
    Oct 24, 2003
    Messages:
    3,255
    +1

    Gotsta have the flow.
     
  17. Arya Ebrahimi

    Arya Ebrahimi SILVER Star

    Joined:
    Dec 2, 2003
    Messages:
    3,235
    Location:
    Rockville, MD
    The wheels on an airplane are free spinning. They are not driven. Therefore it is irrelevant what speed the ground is moving at, it is only relevant what speed the plane is moving in relation to the rest of the earth.

    In short, I concur w/ Baxter650
     
  18. Red Herring

    Red Herring

    Joined:
    Feb 28, 2005
    Messages:
    779
    Location:
    Victopia BC


    I said no initially, but I think I am coming round to your camp! I think your right. It would be different if the engines drove the wheels.
     
  19. rusty_tlc

    rusty_tlc Dain Bramaged Member

    Joined:
    Jun 23, 2005
    Messages:
    11,702
    Location:
    Reno, NV
    If the plane is exerting forward thrust equivelent to 200 knots and the belt is moving backward at 200 knots the net air speed will be zero.
     
  20. LoveTractor

    LoveTractor

    Joined:
    Mar 30, 2005
    Messages:
    470
    Location:
    Mt. Pleasant, SC
    =no wind on front of wing to cause lift. The plane will not move forward because of this conveyor belt system. A plane's engines move the plane forward(without wicked conveyor system) which causes wind on front of wing which causes lift which causes flight. No move forward=no lift=no flight.
     
Thread Status:
Not open for further replies.

Share This Page