Physics 011

MC#10A

Chapter 10: Fluids

 1. Brass has a density of 8.9 g/cm3. A sample of brass is shaped into a perfect cube that has a mass of 71.2 grams. What is the length of each side of the cube?  The correct answer: 2.0 cm See Section 10-1 2. What is the specific gravity of a bar of iron that has a mass of 192 grams and the dimensions 12 cm x 2 cm x 1 cm?  The correct answer: 8.0 See Section 10-1 3. A diver is swimming 10 meters below the surface of the water in a reservoir. There is no current, the air has a pressure of 1 atmosphere, and the density of the water is 1000 kilograms per cubic meter. What is the pressure experienced by the diver?  The correct answer: 1.99 x 105 Pa See Section 10-2 4. A closed-end tube is evacuated and placed with its open end beneath the surface of a reservoir of mercury. The mercury rises to a height of 93 cm. If the density of mercury is 1.36 x 104 kg/m3, what is the pressure at the bottom of the column of mercury? Your answer: 1.24 x 105 Pa 5. Two rectangular water tanks are filled to the same depth with water. Tank A has a bottom surface area of 2 m2 and tank B has a bottom area of 4 m2. Which statement about the forces and pressures at the bottom of the tanks is correct?  The correct answer: Since FA is less than FB, then, PA is equal to PB. See Section 10-2 6. The bottom of each foot of an 80-kg man has an area of about 400 cm2. What is the effect of his wearing snowshoes with an area of about 0.400 m2?  The correct answer: The pressure exerted on the snow becomes 1/10 as great. See Section 10-2 7. In a hydraulic lift the surface of the input piston is 10 cm2 and that of the output piston is 3000 cm2. What is the work done if a 100 N force applied to the input piston raises the output piston by 2.0 meters? Your answer: 60 KJ 8. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. If the pressure at a certain depth ho in the liquid represented by the graph labeled B is Po, the pressure at the same depth in the liquid represented by the graph labeled C would be ___ Po.  The correct answer: less than See Section 10-2 9. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. The liquid with the smallest mass density is represented by the graph labeled ___.  The correct answer: D See Section 10-2 10. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. A certain object just barely floats when dropped into a beaker filled with liquid B. If the same object was dropped into a beaker filled with liquid D, the object ___. Your answer: would definitely sink 11. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. The pressure at a depth ho in the liquid represented by the graph labeled B is Po. The depth in the liquid represented by the graph labeled A at which the pressure will have the same value Po, is ___ ho.  The correct answer: less than See Section 10-2 12. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. The mass density of the liquid represented by the graph labeled C is ___ the mass density of the liquid represented by the graph labeled D. Your answer: more than 13. The pressure in a liquid is measured as a function of depth in the liquid for four different liquids. The results are plotted in the figure at the right. A certain object just barely floats in a beaker filled with liquid B. If the same object was placed in a beaker filled with liquid A, the object ___. Your answer: would definitely float 14. One pound solid pieces of pine wood, lead and aluminum are dropped over the side of a boat in the middle of a deep fresh water lake. The board floats and the two solid pieces of metal sink. The buoyant force acting on the pine board is ___ the buoyant force acting on the aluminum block.  The correct answer: more than See Section 10-6 15. One pound solid pieces of pine wood, lead and aluminum are dropped over the side of a boat in the middle of a deep fresh water lake. The board floats and the two solid pieces of metal sink. The buoyant force acting on the lead block is ___ the buoyant force acting on the aluminum block. The correct answer: less than See Section 10-6 16. One pound solid pieces of pine wood, lead and aluminum are dropped over the side of a boat in the middle of a deep fresh water lake. The board floats and the two solid pieces of metal sink. As the lead block falls toward the bottom of the lake the buoyant force acting on it ___.  The correct answer: remains constant See Section 10-6 17. A balloon is partially inflated with air, tied to a rock and thrown over the side of the boat into a deep fresh water lake. The rock and balloon sink toward the bottom. As the rock and balloon sink toward the bottom, the magnitude of the buoyant force acting on the balloon ___. The correct answer: decreases See Section 10-6 18. A balloon is partially inflated with air, tied to a rock and thrown over the side of the boat into a deep fresh water lake. The rock and balloon sink toward the bottom. As the rock and balloon sink toward the bottom, the magnitude of the buoyant force acting on the rock ___. Your answer: remains constant 19. A balloon is partially inflated with air, tied to a rock and thrown over the side of the boat into a deep fresh water lake. The rock and balloon sink toward the bottom. As the rock and balloon sink toward the bottom, the speed of the rock ___.  The correct answer: increases See Sections 10-6, 4-4 20. Two insoluble bodies, A and B, appear to lose the same amount of weight when submerged in alcohol. Which statement is most applicable?  The correct answer: Both bodies have the same volume. See Section 10-6 21. At 20oC the density of water is 1 g/cm3. What is the density of a body that has a mass of 100 grams in air and an apparent weight of 25 gram weights when suspended in water?  The correct answer: 1.3 g/cm3 See Sections 10-6, 10-1 22. The aorta of a 70 kilogram man has a cross-sectional area of 3.0 square centimeters and carries blood with a velocity of 30 centimeters per second. What is the average volume flow rate?  The correct answer: 90 cm3/s See Section 10-2 23. Consider the laminar flow of an incompressible, non viscous liquid through the plumbing in the figure at the right. The speed of the fluid at point p1 is ___ the speed of the fluid at point p2.   The correct answer: less than See Section 10-7 24. Consider the laminar flow of an incompressible, non viscous liquid through the plumbing in the figure at the right. The volume of the fluid that flows past point p2 in two seconds is ___ the volume of the fluid that flows past point p5 in two seconds. Your answer: equal to 25. Consider the laminar flow of an incompressible, non viscous liquid through the plumbing in the figure at the right. The kinetic energy per unit volume of the liquid at point p1 is ___ the kinetic energy per unit volume of the fluid at point p4.  The correct answer: less than See Section 10-8 26. Consider the laminar flow of an incompressible, non viscous liquid through the plumbing in the figure at the right. The density of the fluid at point p3 is ___ what it is at point p5. Your answer: equal to 27. Consider the laminar flow of an incompressible, non viscous liquid through the plumbing in the figure at the right. The pressure in the fluid at point p1 is ___ the pressure at point p3.  The correct answer: more than See Section 10-8 28. A small diameter copper rod is bent in the shape of a V. A straight piece of the same material of length Lo is laid across the V forming a triangle. The device is dipped into a liquid which has surface tension yo, forming a film of the material within the triangle. The V is then hung upside down as in the figure at the right and the straight rod moves down slightly coming to equilibrium in a horizontal position a distance do below the apex of the V. If the overall length of the moveable rod had been a little longer, its equilibrium position below the apex of the V would have been ___ do.  The correct answer: more than See Section 10-12 29. A small diameter copper rod is bent in the shape of a V. A straight piece of the same material of length Lo is laid across the V forming a triangle. The device is dipped into a liquid which has surface tension yo, forming a film of the material within the triangle. The V is then hung upside down as in the figure at the right and the straight rod moves down slightly coming to equilibrium in a horizontal position a distance do below the apex of the V. If the surface tension of the liquid had been more than yo, when the movable rod came to equilibrium, its position below the apex of the V would have been ___ do. Your answer: less than