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Perplexed again

  1. Nov 24, 2003 #1
    Perplexed again!!!!

    I have two problems that I am stuck on...I don’t even know if I am going about these correctly.

    1. A fountain consists of water jets mounted so that their nozzles are 2 ft above a pool. Each jet squirts water out at a 45o angle. The water lands in the pool approximately 4 feet from the jet. The nozzle on the jet is 0.5 inch in diameter. There are eight of these jets in the fountain. At what rate must water be pumped through the fountain (in gallons/hour)?

    4ft=1.219m, 2ft=.6096m
    1.219m/ cos 45 = 1.7239m
    1.7239 sin 45= 1.219

    1.219+.6096=1.828m how far the water traveled

    v^2=0+2*9.8m/s^2(1.8196-.6069)
    v^2=4.88m/s

    d=.0127m
    A=pi(.0127m)^2
    A=.0005067m^2

    Av=Rvol=.00247m^3/s*4+.00989m^3/s=9404gall/hr

    2.)A precise barometer can be constructed as shown at right. A tube full of some liquid is inverted in a pool of that liquid. The fluid settles into equilibrium, with a vacuum above the fluid. The height of the column of fluid indicates the atmospheric pressure.

    Calculate what h will be for standard atmospheric pressure at sea level if the liquid in the barometer is Water

    I know that I should use bernoulli’s equation
    P1 + gy1 + ½v12 = P2 + gy2 + ½v22
    v1=0 density=1000kg/m^3
    y1=0 P1=101,300N/m^2
    v2=0
    y2=h

    101,300N/m^2=P2+(1000kg/m^6)(9.8N)(h)

    I have two variable (P2 and h) I do not know how to solve the rest? Can anyone help?

    Thanks for your help in advance
     
  2. jcsd
  3. Nov 25, 2003 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Some hints:

    For #1: What's the area of a circle?

    For #2: You don't need the big guns of Bernoulli. This is a statics problem.
     
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