Question

Example 13.4: Pressure in a tube with two liquids/ P. 439 A U-shaped tube is closed at one end; the other end is open to the atmosphere. Water fills the side of the tube that includes the closed end, while oil, floating on the water, fills the side of the tube open to the atmosphere. The two liquids do not mix. The height of the oil above the point where the two liquids touch is 75 cm, while the height of the closed end of the tube above this point is 25 cm. What is the gauge pressure at the closed end? Po Pw 1000 kg/m3 Po = 900 kg/m P3 d- 25 cm Open with Print

Answer 1

Since, point A and P_3 are in same level of height from the bottom. So, Pressure at A and P_3 are same. It means P_A = P_3 Gauge pressure at closed end = Gauge pressure at A = P_A - P_0 Gauge pressure at closed end = P_3 - P_0 (since, P_3 = P_A) = rho_0 g(75 cm - 25 cm) Gauge pressure at closed end = 900 kg/m^3 times 9.8 m/s^2 = 0.50 m since, 1 cm = 0.01 m Gauge pressure at closed end = 4410 Pascal