Choose Correct Answer For Following Pressure & Fluid Statics Flashcards

A container is filled with water and the pressure at the container bottom is P. If the container is instead filled with oil having specific gravity 0.80, what new bottom pressure results? A: a pressure A container is filled with water and the pressure at the bottom of the container is P. Then the container is emptied halfway and topped off with oil of density 0.80 x 10^3 kg/m^3, which floats on top of the water. What is the pressure at the bottom of the container now? A: a pressure At a pressure of 1 atmosphere a column of mercury in a barometer is supported to the height h = 0.76 m. The density of mercury is 13.6 x 10^3 kg/m^3 . A barometer of similar design filled with water would support a column of water how high at a pressure of 1 atmosphere? A: more than ten times h When an artery gets a constricted region due to plaque, how does the pressure in this region compare to the pressure in an unconstricted region adjacent? C: In the constricted region the blood moves at a higher speed than in the unconctricted region resulting in a decreased pressure. An ice cube with a small solid steel sphere frozen inside floats in a glass of water filled to the brim. What happens to the level of water in the glass as a result of the ice melting? C: It goes down Which state of matter is associated with the very highest of temperatures? B: Plasma A copper wire of length 2.0 m, cross sectional area 7.1 × 10−6 m2 and Young’s modulus 11 × 1010 N/m2 has a 200-kg load hung on it. What is its increase in length? (g = 9.8 m/s2) D: 5.0 mm In an elastic solid there is a direct proportionality between strain and: D: Stress The quantity “stress” expressed in terms of the fundamental quantities (mass, length, time) is equivalent to: B: ML-1T-2 The quantity “strain” expressed in terms of the fundamental quantities (mass, length, time) is equivalent to: D: a dimensionless quantity The bulk modulus of a material, as a meaningful physical property, is applicable to which of the following? D: solids, liquids and gases A uniform pressure of 7.0 × 105 N/m2 is applied to all six sides of a copper cube. What is the percentage change in volume of the cube? (for copper, B = 14 × 1010 N/m2) D: 0.5 x 10-3% Bar One has a Young’s modulus that is bigger than that of Bar Two. This indicates Bar One: D: is made of material that is different from Bar Two. Consider two steel rods, A and B. B has three times the area and twice the length of A, so Young’s modulus for B will be what factor times Young’s modulus for A? D: 1.0 A tire stops a car by use of friction. What modulus should we use to calculate the stress and strain on the tire? C: shear modulus How large a force is necessary to stretch a 2.0-mm-diameter steel wire (Y = 2.0 × 1011 N/m2) by 1.0%? B: 6.3 x 103 N The standard kilogram is a platinum-iridium cylinder 39.0 mm in height and 39.0 mm in diameter. What is the density of the material? A: 21.5 g/cm3 The quantity “pressure” expressed in terms of the fundamental quantities (mass, length, time) is equivalent to: B: MLT-1 The pressure inside a commercial airliner is maintained at 1.00 atm (105 Pa). What is the net outward force exerted on a 1.0 m × 2.0 m cabin door if the outside pressure is 0.30 atm? D: 140000 N A stonecutter’s chisel has an edge area of 0.50 cm2. If the chisel is struck with a force of 45 N, what is the pressure exerted on the stone? D: 900,000 PA When water freezes, it expands about nine percent. What would be the pressure increase inside your automobile engine block if the water in there froze? (The bulk modulus of ice is 2.0 × 109 Pa, and 1 atm = 1.0 × 105 Pa.) D: 1800 atm The Greenland ice sheet can be one km thick. Estimate the pressure underneath the ice. (The density of ice is 918 kg/m3.) D: 9.0 x 10^6 Pa(90 atm) What is the total mass of the Earth’s atmosphere? (The radius of the Earth is 6.4 × 106 m, and atmospheric pressure at the surface is 105 N/m2.) C: 5 x 10^18 kg A solid object is made of two materials, one material having density of 2 000 kg/m3 and the other having density of 6 000 kg/m3. If the object contains equal volumes of the materials, what is its average density? B: 4000 kg/m3 A solid object is made of two materials, one material having density of 2 000 kg/m3 and the other having density of 6 000 kg/m3. If the object contains equal masses of the materials, what is its average density? a. 3 000 kg/m3 b. 4 000 kg/m3 c. 5 300 kg/m3 d. more information is needed A: 3000 kg/m3 What is the total force on the bottom of a 2.0-m-diameter by 1.0-m-deep round wading pool due to the weight of the air and the weight of the water? (Note the pressure contribution from the atmosphere is 1.0 × 105 N/m2, the density of water is 1 000 kg/m3, and g = 9.8 m/s2.) a. 3.4 × 105 N b. 2.4 × 106 N c. 3.2 × 106 N d. 6.0 × 106 N A: 3.4 x 105 N In a large tank of liquid, the hydrostatic pressure at a given depth is a function of: a. depth. b. surface area. c. liquid density. d. Choices a and c are both valid. D: choices a and c are both valid A 15 000-N car on a hydraulic lift rests on a cylinder with a piston of radius 0.20 m. If a connecting cylinder with a piston of 0.040-m radius is driven by compressed air, what force must be applied to this smaller piston in order to lift the car? a. 600 N b. 1 500 N c. 3 000 N d. 15 000 N A: 600 N 24. By what factor is the total pressure greater at a depth of 850 m in water than at the surface where pressure is one atmosphere? (water density = 1.0 × 103 kg/m3, 1 atmosphere pressure = 1.01 × 105 N/m2, and g = 9.8 m/s2) a. 100 b. 83 c. 74 d. 19 B: 83 If the column of mercury in a barometer stands at 72.6 cm, what is the atmospheric pressure? (The density of mercury is 13.6 × 103 kg/m3 and g = 9.80 m/s2) a. 0.968 × 105 N/m2 b. 1.03 × 105 N/m2 c. 0.925 × 105 N/m2 d. 1.07 × 105 N/m2 A: 0.968 x 105 N/m2 Dams at two different locations are needed to form a lake. When the lake is filled, the water level will be at the top of both dams. The Dam #2 is twice as high and twice as wide as Dam #1. How much greater is the force of the water on Dam #2 than the force on Dam #1? (Ignore atmospheric pressure; it is pushing on both sides of the dams.) a. 2 b. 4 c. 8 d. 16 C: 8 Atmospheric pressure is 1.0 × 105 N/m2, and the density of air is 1.29 kg/m3. If the density of air is constant as you get higher and higher, calculate the height of the atmosphere needed to produce this pressure. a. 7 900 m b. 77 000 m c. 1 260 m d. 10 300 m A: 7900 m The water behind Grand Coulee Dam is 1 200 m wide and 150 m deep. Find the hydrostatic force on the back of the dam. (Hint: the total force = average pressure × area) a. 5.2 × 109 N b. 8.8 × 1010 N c. 13.2 × 1010 N d. 18.0 × 1010 N C: 13.2 x 10^10N How deep under the surface of a lake would the pressure be double that at the surface? (1 atm = 1.01 × 105 Pa) a. 1.00 m b. 9.80 m c. 10.3 m d. 32.2 m C: 10.3 m A piece of aluminum has density 2.70 g/cm3 and mass 775 g. The aluminum is submerged in a container of oil (oil’s density = 0.650 g/cm3). How much oil does the metal displace? a. 287 cm3 b. 309 cm3 c. 232 cm3 d. 1 125 cm3 A: 287 cm3 A piece of aluminum has density 2.70 g/cm3 and mass 775 g. The aluminum is submerged in a container of oil of density 0.650 g/cm3. A spring balance is attached with string to the piece of aluminum. What reading will the balance register in grams (g) for the submerged metal? a. 960 g b. 775 g c. 588 g d. 190 g C: 588 g A block of wood has density 0.50 g/cm3 and mass 1 500 g. It floats in a container of oil (the oil’s density is 0.75 g/cm3). What volume of oil does the wood displace? a. 3 000 cm3 b. 2 000 cm3 c. 1 500 cm3 d. 1 000 cm3 B: 2000 cm3 What volume of water is displaced by a submerged 2.0-kg cylinder made of solid aluminum? (aluminum density = 2.7 × 103 kg/m3 and water density = 1.0 × 103 kg/m3) a. 7.4 × l0−4 m3 b. 1.4 × 103 m3 c. 9.9 × 103 m3 d. 6.0 × 102 m3 A: 7.4 x 10-4 m3 A ping-pong ball has an average density of 0.0840 g/cm3 and a diameter of 3.80 cm. What force would be required to keep the ball completely submerged under water? a. 1.000 N b. 0.788 N c. 0.516 N d. 0.258 N D: 0.258 N A cube of wood of density 0.78 g/cm3 is 10 cm on a side. When placed in water, what height of the block will float above the surface? (water density = 1.00 g/cm3) a. 7.8 cm b. 5.0 cm c. 2.2 cm d. 6.4 cm C: 2.2 cm The bottom of a flat-bottomed aluminum boat has an area of 4.0 m2 and the boat’s mass is 60 kg. When set afloat in water, how far below the water surface is the boat bottom? (water density = 1.0 × 103 kg/m3) a. 0.060 m b. 0.015 m c. 0.030 m d. 0.075 m B: 0.015 m The bottom of a flat-bottomed aluminum boat has area = 4.0 m2 and mass = 60 kg. If two fishermen and their fishing gear with total mass of 300 kg are placed in the boat, how much lower will the boat ride in the water? (H2O density = 1.0 × 103 kg/m3) a. 0.15 m b. 0.090 m c. 0.075 m d. 0.060 m C: 0.075 m 38. Legend says that Archimedes, in determining whether or not the king’s crown was made of pure gold, measured its volume by the water displacement method. If the density of gold is 19.3 g/cm3, and the crown’s mass is 600 g, what volume would be necessary to prove that it is pure gold? a. 31.1 cm3 b. 114 × 103 cm3 c. 22.8 × 103 cm3 d. 1.81 × 10−2 cm3 A: 31.1 cm3 A solid rock, suspended in air by a spring scale, has a measured mass of 9.00 kg. When the rock is submerged in water, the scale reads 3.30 kg. What is the density of the rock? (water density = 1 000 kg/m3) a. 4.55 × 103 kg/m3 b. 3.50 × 103 kg/m3 c. 1.20 × 103 kg/m3 d. 1.58 × 103 kg/m3 D: 1.58 x 103 kg/m3 As ice floats in water, about 10% of the ice floats above the surface of the water. If we float some ice in a glass of water, what will happen to the water level as the ice melts? a. The water level will rise 10% of the volume of the ice that melts. b. The water level will rise, but not as much as the 10% indicated in answer a. c. The water level will remain unchanged. d. The water level will become lower. C: the water level will remain unchanged A large stone is resting on the bottom of the swimming pool. The normal force of the bottom of the pool on the stone is equal to the: a. weight of the stone. b. weight of the water displaced. c. sum of the weight of the stone and the weight of the displaced water. d. difference between the weight of the stone and the weight of the displaced water D: difference between the weight of the stone and the weight of the displaced water. A blimp is filled with 400 m3 of helium. How big a payload can the balloon lift? (The density of air is 1.29 kg/m3; the density of helium is 0.18 kg/m3.) a. 111 kg b. 129 kg c. 215 kg d. 444 kg D: 444 kg A heavily loaded boat is floating in a pond. The boat sinks because of a leak. What happens to the surface level of the pond? a. It stays the same. b. It goes up. c. It goes down. d. More information is needed to reach a conclusion. C: it goes down A heavily loaded boat is floating in a pond. The boat starts to sink because of a leak but quick action plugging the leak stops the boat from going under although it is now deeper in the water. What happens to the surface level of the pond? a. It stays the same. b. It goes up. c. It goes down. d. More information is needed to reach a conclusion. A: it stays the same A block of wood has specific gravity 0.80. When placed in water, what percent of the volume of the wood is above the surface? a. 0, the block sinks. b. 20% c. 25% d. 80% B: 20% An ideal fluid flows through a pipe made of two sections with diameters of 1.0 and 3.0 inches, respectively. The speed of the fluid flow through the 3.0-inch section will be what factor times that through the 1.0-inch section? a. 6.0 b. 9.0 c. 1/3 d. 1/9 D: 6.0 47. The flow rate of a liquid through a 2.0-cm-radius pipe is 0.008 0 m3/s. The average fluid speed in the pipe is: a. 0.64 m/s. b. 2.0 m/s. c. 0.040 m/s. d. 6.4 m/s. D: 6.4 m/s 48. Think of Bernoulli’s equation as it pertains to an ideal fluid flowing through a horizontal pipe. Imagine that you take measurements along the pipe in the direction of fluid flow. What happens to the sum of the pressure and energy per unit volume? a. It increases as the pipe diameter increases. b. It decreases as the pipe diameter increases. c. It remains constant as the pipe diameter increases. d. No choices above are valid. c: it remains constant as the pipe diameter increases 49. An ideal fluid, of density 0.85 × 103 kg/m3, flows at 0.25 kg/s through a pipe of radius 0.010 m. What is the fluid speed? a. 0.85 m/s b. 1.3 m/s c. 3.0 m/s d. 0.94 m/s d. 0.94 m/s 50. An ideal fluid, of density 0.90 × 103 kg/m3, flows at 6.0 m/s through a level pipe with radius of 0.50 cm. The pressure in the fluid is 1.3 × 105 N/m2. This pipe connects to a second level pipe, with radius of 1.5 cm. Find the speed of flow in the second pipe. a. 54 m/s b. 18 m/s c. 0.67 m/s d. 0.33 m/s c. 0.67 m/s 51. The flow rate of blood through the average human aorta, of radius 1.0 cm, is about 90 cm3/s. What is the speed of the blood flow through the aorta? a. 14 cm/s b. 32 cm/s c. 37 cm/s d. 29 cm/s d. 29 cm/s 52. Water (density = 1 × 103 kg/m3) flows at 15 m/s through a pipe with radius 0.040 m. The pipe goes up to the second floor of the building, 3.0 m higher, and the pressure remains unchanged. What is the speed of the water flow in the pipe on the second floor? a. 13 m/s b. 14 m/s c. 15 m/s d. 16 m/s a. 13 m/s 53. Water (density = 1 × 103 kg/m3) flows at 10 m/s through a pipe with radius 0.030 m. The pipe goes up to the second floor of the building, 2.0 m higher, and the pressure remains unchanged. What is the radius of the pipe on the second floor? a. 0.046 m b. 0.034 m c. 0.015 m d. 0.012 m b. 0.034 m 54. Air pressure is 1.0 × 105 N/m2, air density is 1.3 kg/m3, and the density of soft drinks is 1.0 × 103 kg/m3. If one blows carefully across the top of a straw sticking up 0.100 m from the liquid in a soft drink can, it is possible to make the soft drink rise half way up the straw and stay there. How fast must the air be blown across the top of the straw? a. 76 m/s b. 27 m/s c. 19 m/s d. 0.99 m/s b. 27 m/s 55. A hole is poked through the metal side of a drum holding water. The hole is 18 cm below the water surface. What is the initial speed of outflow? a. 1.9 m/s b. 2.96 m/s c. 3.2 m/s d. 3.5 m/s a. 1.9 m/s 56. Water comes down the spillway of a dam from an initial vertical height of 170 m. What is the highest possible speed of the water at the end of the spillway? a. 15 m/s b. 25 m/s c. 58 m/s d. 1 370 m/s c. 58 m/s 57. Water pressurized to 3 × 105 Pa is flowing at 5.0 m/s in a pipe which contracts to 1/3 of its former area. What are the pressure and speed of the water after the contraction? (Density of water = 1 × 103 kg/m3.) a. 2 × 105 Pa, 15 m/s b. 3 × 105 Pa, 10 m/s c. 3 × 105 Pa, 15 m/s d. 4 × 105 Pa, 1.5 m/s a. 2 × 105 Pa, 15 m/s 58. A fountain sends water to a height of 100 m. What must be the pressurization (above atmospheric) of the underground water system? (1 atm = 105 N/m2) a. 1 atm b. 4.2 atm c. 7.2 atm d. 9.8 atm b. 4.2 atm 59. The Garfield Thomas water tunnel at Pennsylvania State University has a circular cross-section that constricts from a diameter of 3.6 m to the test section, which is 1.2 m in diameter. If the speed of flow is 3.0 m/s in the large-diameter pipe, determine the speed of flow in the test section. a. 9.0 m/s b. 18 m/s c. 27 m/s d. 1.0 m/s c. 27 m/s 60. A Boeing-737 airliner has a mass of 20 000 kg. The total area of the wings is 100 m2. What must be the pressure difference between the top and bottom of the wings to keep the airplane up? a. 1 960 Pa b. 3 920 Pa c. 7 840 Pa d. 15 700 Pa a. 1 960 Pa 61. How much air must be pushed downward at 40.0 m/s to keep an 800-kg helicopter aloft? a. 98.0 kg/s b. 196 kg/s c. 294 kg/s d. 392 kg/s b. 196 kg/s 62. A jet of water flowing from a hose at 15 m/s is directed against a wall. If the mass flow in the fluid stream is 2.0 kg/s, what force is the water applying to the wall if backsplash is negligible? a. 30 N b. 40 N c. 65 N d. 127 N a. 30 N 63. A Venturi tube may be used as the inlet to an automobile carburetor. If the inlet pipe of 2.0 cm diameter narrows to 1.0 cm diameter, what is the pressure drop in the constricted section for airflow of 3.0 m/s in the 2-cm section? (Assume air density is 1.25 kg/m3.) a. 70 Pa b. 84 Pa c. 100 Pa d. 115 Pa b. 84 Pa 64. Water is sent from a fire hose at 30 m/s at an angle of 30° above the horizontal. What is the maximum height reached by the water? a. 7.5 m b. 11 m c. 15 m d. 19 m b. 11 m 65. How much power is theoretically available from a mass flow of 1 000 kg/s of water that falls a vertical distance of 100 m? a. 980 kW b. 98 kW c. 4 900 W d. 980 W a. 980 kW 66. A fluid is drawn up through a tube as shown below. The atmospheric pressure is the same at both ends. Use Bernoulli’s equation to determine the speed of fluid flow out of the tank. If the height difference from the top of the tank to the bottom of the siphon is 1.0 m, then the speed of outflow is: a. 1.1 m/s. b. 2.2 m/s. c. 4.4 m/s. d. 8.8 m/s. c. 4.4 m/s 67. It takes 2.0 minutes to fill a gas tank with 40 liters of gasoline. If the pump nozzle is 1.0 cm in radius, what is the average speed of the gasoline as it leaves the nozzle? (1 000 liters = one cubic meter) a. 0.27 m/s b. 1.1 m/s c. 11 m/s d. 64 m/s b. 1.1 m/s 69. A unit for viscosity, the centipoise, is equal to which of the following? a. 10-3 N·s/m2 b. 10-2 N·s/m2 c. 10-1 N·s/m2 d. 102 N·s/m2 a. 10-3 N·s/m2 71. A fluid has a density of 1 040 kg/m3. If it rises to a height of 1.8 cm in a 1.0-mm diameter capillary tube, what is the surface tension of the liquid? Assume a contact angle of zero. a. 0.046 N/m b. 0.056 N/m c. 0.092 N/m d. 0.11 N/m a. 0.046 N/m 73. In order to overcome a surface tension of a fluid, a force of 1.32 × 10-2 N is required to lift a wire ring of circumference 12.0 cm. What is the surface tension of the fluid? a. 0.055 N/m b. 0.11 N/m c. 0.035 N/m d. 0.018 N/m a. 0.055 N/m 75. Spherical particles of density 2.0 g/cm3 are shaken in a container of water (viscosity = 1.0 × 10-3 N·s/m3). The water is 8.0 cm deep and is allowed to stand for 30 minutes. What is the greatest terminal velocity of the particles still in suspension at that time? a. 0.55 × 10-5 m/s b 1.1 × 10-5 m/s c. 2.2 × 10-5 m/s d. 4.4 × 10-5 m/s d. 4.4 × 10-5 m/s 77. A centrifuge rotates at 100 rev/s (i.e., 628 rad/s). If the test tube places the suspension at 8.0 cm from the axis of rotation, by what factor are the terminal speeds of the settling particles increased as compared to sedimentation cause by gravity? a. 3.2 × 102 b. 64 c. 800 d. 3.9 × 105 a. 3.2 × 102 78. Which of the following characterizes the net force on a particle falling through a fluid at its terminal speed? a. It is at a maximum. b. It is upwards. c. It is downwards. d. It is zero. d. It is zero. A room in a house has a floor area of 120 ft2. Which of the following is most likely the approximate volume of the room? a. 3 m3 b. 30 m3 c. 300 m3 d. 3 000 m3 b. 30 m3 C3. How long has it been that scientists have accepted that the nucleus of the atom consists of neutrons and protons? Think of your answers in terms of order of magnitude. a. about a decade b. about a century c. about a thousand years d. since Aristotle b. about a century C5. There are other ways of expressing uncertainty besides significant figures. For example, suppose a quantity is known to have a value between 20.4 and 20.0 and our best estimate of the value is midrange at 20.2. We could write the number as 20.2 +/- 0.2 and say that the number has a 1% uncertainty. We would also say it has 3 significant figures. If we square a number with 1% uncertainty (i.e., 2 parts in about 200) and 3 significant figures, what results? a. A number with 1% uncertainty and 3 significant figures. b. A number with 2% uncertainty and 3 significant figures. c. A number with 2% uncertainty and 2 significant figures. d. A number with 1% uncertainty and 2 significant figures. b. A number with 2% uncertainty and 3 significant figures. 2. Since 1967 the standard definition for the second has been based on which of the following? a. characteristic frequency of the cesium-133 atom b. average solar day c. sidereal day d. Greenwich Civil Time a. characteristic frequency of the cesium-133 atom 4. The prefixes which are abbreviated p, n, and G represent which of the following? a. 10-2, 10-6, and 1015 b. 10-9, 106, and 1010 c. 10-12, 10-9, and 109 d. 10-15, 10-6, and 1012 c. 10-12, 10-9, and 109 6. One year is about ________ seconds while one day is exactly ________ seconds. a. 3.16 × 107, 86 400 b. 5.26 × 105, 86 400 c. 3.16 × 107, 8 640 d. 1.04 × 106, 36 000 a. 3.16 × 107, 86 400 8. When was the existence of the neutron confirmed? a. in ancient times b. in 1895 c. in 1932 d. in 1969 c. in 1932 10. Which formula is dimensionally consistent with an expression yielding a value for velocity? (a is acceleration, x is distance, and t is time) a. v/t2 b. vx2 c. v2/t d. at d. at 12. If the displacement of an object, x, is related to velocity, v, according to the relation x = Av, the constant, A, has the dimension of which of the following? a. acceleration b. length c. time d. area c. time 14. If a is acceleration, v is velocity, x is position, and t is time, then which equation is not dimensionally correct? a. t = x/v b. a = v2/x c. v = a/t d. t2 = 2x/a c. v = a/t 16. Areas always have dimensions ____ while volumes always have dimensions ____. a. m2, m3 b. L2, L3 c. Both a and b are correct. d. No answer is correct because of the “always”. b. L2, L3 18. Which one of the choices below represents the preferred practice regarding significant figures when multiplying the following: 10.5 × 8.8 × 3.14? a. 290 b. 290.136 c. 290.1 d. 300 a. 290 20. The length and width of a standard sheet of paper is measured, and then the area is found by calculation to be 93.50 in2. The number of significant figures in the width measurement must be at least: a. 1. b. 2. c. 3. d. 4. d. 4. 22. Multiplying a 2 significant figure number by a 3 significant figure number and then dividing the product by a six significant figure number yields a number with how many significant figures? a. 5/6 b. 1 c. 2 d. 11 c. 2 24. On planet Z, the standard unit of length is the foose. Ann the Astronaut is 5.90 feet tall on earth. She lands on planet Z and is measured to be 94 foosi tall. Her partner Rachael is 88 foosi tall. How tall is Rachael on Earth? a. 5.2 feet b. 5.5 feet c. 5.8 feet d. 6.3 feet b. 5.5 feet 26. A cereal box has the dimensions of 0.19 m × 0.28 m × 0.070 m. If there are 3.28 feet per meter, then what is the volume of the box in cubic feet? a. 0.13 cubic feet b. 0.040 cubic feet c. 0.012 cubic feet d. 0.003 7 cubic feet a. 0.13 cubic feet 28. A cement truck can pour 20 cubic yards of cement per hour. Express this in ft3/min. a. 1/3 ft3/min b. 1.0 ft3/min c. 3 ft3/min d. 9 ft3/min d. 9 ft3/min 30. When NASA was communicating with astronauts on the moon, the time from sending on the Earth to receiving on the moon was 1.28 s. Find the distance from Earth to the moon. (The speed of radio waves is 3.00 × 108 m/s.) a. 240 000 km b. 384 000 km c. 480 000 km d. 768 000 km b. 384 000 km 32. The information on a one-gallon paint can is that the coverage, when properly applied, is 450 ft2. One gallon is 231 in3. What is the average thickness of the paint in such an application? a. 0.003 6 in b. 0.009 0 in c. 0.043 in d. 0.051 in a. 0.003 6 in 34. A physics class in a large lecture hall has 150 students. The total mass of the students is about ______ kg. a. 102 b. 103 c. 104 d. 105 c. 104 36. Which point is nearest the x-axis? a. (−3, 4) b. (4, 5) c. (−5, 3) d. (5, −2) d. (5, −2) 38. If point A is located at coordinates (5, 3) and point B is located at coordinates (-3, 9), what is the distance from A to B if the units of the coordinated system are meters? a. 14 m b. 10 m c. 8 m d. 17 m b. 10 m 40. A right triangle has sides 5.0 m, 12 m, and 13 m. The smallest angle of this triangle is nearest: a. 21°. b. 23°. c. 43°. d. Not attainable since this is not a right triangle. b. 23° 42. A triangle has sides of length 7.0 cm and 25 cm. If the triangle is a right triangle, which of the following could be the length of the third side? a. 18 cm b. 24 cm c. 27 cm d. 32 cm b. 24 cm 44. Note the expression: y = x2. Which statement is most consistent with this expression? a. if y doubles, then x quadruples b. y is greater than x c. if x doubles, then y doubles d. if x doubles, then y quadruples d. if x doubles, then y quadruples 46. For which of the values below is x > x3? a. x = −1.5 b. x = 0 c. x = 1.0 d. x = 1.5 a. x = −1.5 48. The basic function of an automobile’s carburetor is to atomize the gasoline and mix it with air to promote rapid combustion. Assume that 30 cm3 of gasoline is atomized into N spherical droplets. Each droplet has a radius of 2.0 × 10−5 m. Find the total surface area of these N spherical droplets. a. 2 100 cm2 b. 15 000 cm2 c. 18 000 cm2 d. 45 000 cm2 d. 45 000 cm2 50. Doubling the radius of a sphere results in increasing its volume by a factor of a. 2 b. 4 c. 8 d. 8 π c. 8