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Physics lift on a plane

  1. Nov 21, 2003 #1
    hey guys i just found this site and its very helpful. so if u guys can help. it will be greatly appreciated
    i have this problem to solve but i stuck on solveing for the height of the airplane to find the force.
    so if anyone can assist me it will be great.

    Lift on an Airplane. Air streams horizontally past a small airplane's wings such that the speed is 75. over the top surface and 58.5 past the bottom surface.

    If the plane has mass 1250 and a wing area of 14.9 , what is the net vertical force (including the effects of gravity) on the airplane? The density of the air is 1.2 . Take the free fall acceleration to be 9.8 .

    find force in N.
  2. jcsd
  3. Nov 21, 2003 #2

    Doc Al

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    Staff: Mentor

    What I suspect is that they want you to apply Bernoulli's equation to the airflow across top and bottom to find the pressure difference. That pressure difference will produce a net force (of the air on the plane, ignoring drag) acting upward. The weight of the plane acts downward.

    (Whether you can really justify using Bernoulli in this case is another story. Just do the exercise!)
  4. Nov 26, 2003 #3
    Lift on an Airplane

    this how i did it
    solve for delta p=1/2(rho)(velocityoftop)^2 - 1/2(rho)(velocityofbottom)^2
    Lift = delta p*cross sectional area
    force of lift = lift - (m*g) <-mass of plane

    email your number and your address and your brain

    too easy [zz)]
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