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Homework Help: Pressure and Bernoulli + Continuity

  1. Nov 18, 2011 #1
    1. The problem statement, all variables and given/known data

    Water flows through a horizontal tapered pipe. At the wide end its speed is 4.0 m/s and at the narrow end it is 5.0 m/s. The pressure in the wide pipe is 2.5 x 10^5 Pa. What is the pressure in the narrow pipe?

    a. 2.5 x 10^2 Pa
    b. 3.4 x 10^3 Pa
    c. 4.5 x 10^3 Pa
    d. 2.3 x 10^5 Pa
    e. 8.0 x 10^5 Pa

    2. Relevant equations

    P1+1/2*ρ*v12 = P2+1/2*ρ*v22
    A1*v1=A2*v2

    3. The attempt at a solution

    1-wide
    2-narrow

    P1+1/2*ρ*v12 = P2+1/2*ρ*v22

    2.5 x 10^5 Pa + 1/2*1000kg/m3*(4m/s)2=P2 + 1/2*1000kg/m3*(5m/s)2

    2.5 x 10^5 Pa + 1/2*1000kg/m3*(4m/s)2- 1/2*1000kg/m3*(5m/s)2=P

    2.5 x 10^5 Pa + 1/2*1000kg/m3*[(4m/s)2-(5m/s)2]=P

    2.455x10^5 Pa=P

    the answer is not in the options :s can someone tell me what i did wrong?
     
    Last edited: Nov 18, 2011
  2. jcsd
  3. Nov 18, 2011 #2
    I agree with your answer. Looks like an error in supplied answer.
     
  4. Nov 18, 2011 #3
    thanks! :)
     
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