FIGURE 15-9 -Water Flows in a Pipe as Shown in Figure 15-9

Multiple Choice

FIGURE 15-9
-Water flows in a pipe as shown in Figure 15-9. The pipe is horizontal at points A and B, where it has a diameter of 3.00 cm and the water is moving at 2.00 m/s. The pipe then rises 2.00 m in elevation while decreasing in diameter and is again horizontal at points C and D, where it has a diameter of 2.00 cm. Vertical tubes, open at the top, are connected to the pipe at A and C, flush with the edge of the pipe. The vertical tubes at B and D are also open at the top, but these enter the pipe and bend at right angles along the centerline of the pipe with their mouths facing the flow (these are Pitot tubes) . Water enters the Pitot tube and rises until the hydrostatic pressure in the tube balances the pressure at the mouth of the tube. Because no more water enters the tube, the speed of the water just outside the mouth of the tube is zero m/s. The pressure in the pipe is unaffected by the Pitot tube. What is the difference in elevation (h_D - h_A) ?

A) 21.8 cm
B) 18.7 cm
C) 20.4 cm
D) 0 cm
E) 2.00 m