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Homework Help: Bernoulli Principle Problem

  1. Apr 12, 2008 #1
    1. The problem statement, all variables and given/known data

    Find the lift in newtons due to the Bernoulli Principle on a wing of a plane of area 84.5 m^2 if the air passes over the top and the bottom surfaces at speeds of 347m/s and 289 m/s

    2. Relevant equations

    P1+(1/2)densityV^2 =P2+(1/2)densityV^2

    3. The attempt at a solution

    Ok so i know the density of air is 1.29kg/m^3

    so i plug into equation to get

    1/2(1.29kg/m^3)(347m/s)^2= 1/2(1.29kg/m^3)(289m/s)^2

    then i get answer of 5.39x10^4 N/m^2

    then i use equation F=PA

    and P is 5.39x10^4 N/m^2 and A is 84.5m^2

    to get answer of 4.6x10^6 N

    Am i correct ?
  2. jcsd
  3. Apr 13, 2008 #2
    By bernouili equation
    Pa+1/2pva^2 = Pb =1/2pvb^2
    1/2pvb^2-1/2pva^2 =Pa-Pb
    deltaP = 1/2pvb^2-1/2pva^2
    deltaP * A =Lift force
    I think your method is correct
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