physics

The water supply of a building is fed through a main entrance pipe 6cm in diameter. A 2cm diameter faucet tap positioned 2m above the main pipe fills a 25 liter container in 30s. (a) What is the speed at which the water leaves the faucet? (b) What is the gauge pressure in the main pipe? (Assume that the faucet is the only outlet in the system.)

(a) (25x10^3cm^3)/(pix30s)=2.7m/s
(b) P-Pa=pgh
I am unsure what to plug in for h.
(1000kg/m^3)(9.8m/s^2)(h)
(answer (b): 2.3x10^5 Pa)

  1. 👍 0
  2. 👎 0
  3. 👁 354
  1. (a) V = (Volume flow rate)/(faucet area)
    =25*10^3 cm^3/(30 s* pi cm^2)= 265 cm/s = 2.7 m/s Correct

    (b) The pressure is ambient (Po) at the faucet exit, where the water is flowing. Use this form of the Bernolli equation:
    P + (1/2) rho V^2 + rho*g y = constant

    Let Po be ambient pressure, P1 be the pressure in the entrance pipe, and V1 be the velocity there, which will be 1/9 of the velocity in the faucet, due to the larger diameter. (since V*Area = constant)
    Therefore
    Po + (1/2) rho V2^2 =
    P1 + (1/2)rho V1^2 + rho g h
    The gauge pressure is P1-Po
    = (1/2)rho (V2^2 - V1^2) - rho g h
    Substitute V1 = 2.7 m/s, V2 = 0.3 m/s and solve. h = 2m

    1. 👍 0
    2. 👎 0
    posted by drwls

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    A liquid of density 1354 kg/m^3 flows with speed 2.45 m/s into a pipe of diameter 0.29 m. The diameter of the pipe decreases to 0.05 m at its exit end. The exit end of the pipe is 7.82 m lower than the entrance of the pipe, and

    asked by michelle on November 29, 2012
  2. Physic

    Water enters a horizontal pipe with a rectangular cross section at a speed of 1.00 m/s. The width of the pipe remains constant but the height decreases. 27.3 m from the entrance, the height is half of what it is at the entrance.

    asked by mican on April 18, 2014
  3. physics

    Water enters a horizontal pipe with a rectangular cross section at a speed of 1.00 m/s. The width of the pipe remains constant but the height decreases. 27.3 m from the entrance, the height is half of what it is at the entrance.

    asked by suzan on April 19, 2014
  4. physics

    Please help me !!! for solution of this question Water enters a horizontal pipe with a rectangular cross section at a speed of 1.00 m/s. The width of the pipe remains constant but the height decreases. 27.3 m from the entrance,

    asked by suzan on April 19, 2014
  5. physics

    Water is flowing through a horizontal pipe of varying cross section. At section 1,the diameter is 12cm at a pressure of 80000 Pa. At section 2, the pipe has a diameter of 6cm and the pressure is 60000 Pa. Find the speed of water

    asked by Haiano on June 9, 2014
  6. Physics

    A horizontal water pipe goes from a large diameter to a small diameter and then back to the first diameter as shown in the figure below. The level of water (8cm in the larger tube and 4 cm in the constricted tube) in the small

    asked by Anna on December 4, 2015
  7. physics

    A horizontal pipe (Venturi Tube) 10.0 cm in diameter has a smooth reduction to a pipe 5.00 cm in diameter. If the pressure of the water in the larger pipe is 2.0 x 105 Pa and the pressure in the smaller pipe is 5.0 x 104 Pa, at

    asked by Anonymous on May 30, 2016
  8. physics

    A horizontal pipe (Venturi Tube) 10.0 cm in diameter has a smooth reduction to a pipe 5.00 cm in diameter. If the pressure of the water in the larger pipe is 8.0 x 105 Pa and the pressure in the smaller pipe is 3.0 x 104 Pa, at

    asked by Anonymous on May 31, 2016
  9. Physics

    Please someone help..A horizontal pipe 10.0cm in diameter has a smooth reduction to a pipe 5.0cm in diameter. If the pressure of the water in the large pipe is 80000Pa and the pressure in the small pipe is 60000Pa at what rate

    asked by Waim Mathew on June 15, 2017
  10. Physics

    Water at a pressure of 4.20 atm at street level flows into an office building at a speed of 0.65 m/s through a pipe 6.60 cm in diameter. The pipes taper down to 2.20 cm in diameter by the top floor, 28.0 m above. Calculate the

    asked by Trish on November 9, 2016

More Similar Questions