Page 226 - Schaum's Outline of Theory and Problems of Applied Physics
P. 226

CHAP. 17]                            FLUIDS IN MOTION                                 211



                                         1
        17.11. How many kilograms of milk can a -hp pump in a dairy transfer per hour from one tank to another in which the
                                         3
               liquid level is 10 m higher? Assume 70 percent efficiency.
                                                                  3
        17.12. A pump in a fuel station is required to deliver gasoline (dg = 42 lb/ft ) at the rate of 30 gal/min. If the gasoline
               must be raised through 6 ft and the efficiency is 75 percent, find the minimum power rating of the pump motor.
        17.13. Water leaves the safety valve of a boiler at a velocity of 100 ft/s. What is the gauge pressure in the boiler?

        17.14. A horizontal pipe 15 cm in diameter has a constriction 7.5 cm in diameter. If the velocity of water in the constriction
               is 10 m/s, find the difference between the pressure there and that in the rest of the pipe. Which pressure is the greater?

                                                                                         2
        17.15. Water enters the pipe shown in Fig. 17-4 from the left at a velocity of 10 ft/s and a pressure of 22 lb/in. . Find (a)
               the velocity with which water leaves the pipe at the right, (b) the pressure there, and (c) the rate of flow of water
               through the pipe in pounds per minute.




                                    1 in.
                                         1
                                    10 ft
                                                                  3 in.




                                                               2
                                                 Fig. 17-4



                                                     2
        17.16. A horizontal pipe whose cross-sectional area is 10 cm is connected to another horizontal pipe whose cross-sectional
                        2
               area is 50 cm . Water flows into the small pipe at 6 m/s under a pressure of 200 kPa. Find (a) the speed of the water
               in the large pipe, (b) the pressure there, and (c) the rate of flow.
        17.17. A typical capillary blood vessel is 1 mm long and has a radius of 2 µm. If the pressure difference between its ends is
               20 torr, at what velocity does blood flow through the capillary? At body temperature, the viscosity of blood is about
               2 × 10 −3  P.
        17.18. Establish whether the flow of water in the hose of Prob. 17.6 is laminar or turbulent by calculating its Reynolds
               number.



                               Answers to Multiple-Choice Questions



        17.1. (a)         17.6. (c)
        17.2. (b), (c), (d)  17.7. (a)

        17.3. (c)         17.8. (c)

        17.4. (a)         17.9. (d)

        17.5. (a)        17.10. (c)
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