**Test Bank Physics Principles with Applications -7th Edition-Giancoli**

## Chapter 6 Sample

Exam

Name___________________________________

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1)Substance A has a density of 3 g/cm3 and substance B has a density of 4 g/cm3. In order to obtain1) equal masses of these two substances, what must be the ratio of the volume of A to the volume of B? A)*V*A3B)*V*A 3C)*V*A 1D)*V*A 4E)*V*A 3 = = = = = *V*B*V*B *V*B *V*B *V*B 4 1 3 3 4 2)A hollow sphere of negligible mass and radius *R* is completely filled with a liquid so that its 2) density is *ρ*. You now enlarge the sphere so its radius is 2*R* and completely fill it with the same liquid. What is the density of the enlarged sphere? A) 8 *ρ* B) *ρ* C) *ρ*/2 D) *ρ*/8 E) 4 *ρ* 3)A styrofoam sphere of radius *R* has a density *ρ*. You now carefully compress the sphere so its3) radius is *R*/2. What is the density of the compressed sphere? A) 4 *ρ* B) *ρ* *8* C) 8 *ρ* D) *ρ* *2*E) 2 *ρ* 4)When a box rests on a round sheet of wood on the ground, it exerts an average pressure *p* on the4) wood. If the wood is replaced by a sheet that has half the diameter of the original piece, what is the new average pressure? A) *p* 2 B) *p*/2 C) 2*p* D) 4*p* E) *p*/4 5)When a heavy metal block is supported by a cylindrical vertical post of radius *R*, it exerts a force *F*5) on the post. If the diameter of the post is increased to 2*R*, what force does the block now exert on the post? A) *F*/2 B) 2*F* C) *F*/4 D) *F*/2 E) *F* 6)As shown in the figure, fluid fills a container having several sections. At which of the indicated6) points is the pressure greatest?

- AC
- B

- D
- The pressure is the same at each of the labeled points.

1

7)Consider a brick that is totally immersed in water, with the long edge of the brick vertical. The7) pressure on the brick is A) greatest on the face with largest area. B) greatest on the top of the brick. C) greatest on the bottom of the brick. D) greatest on the sides of the brick. E) the same on all surfaces of the brick. 8)An air bubble underwater has the same pressure as that of the surrounding water. As the air8) bubble rises toward the surface (and its temperature remains constant), the volume of the air

bubble

- A) increases.
- B) remains constant.
- C) decreases.
- D) increases or decreases, depending on the rate it rises.

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

9) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always9)

keeping the top and bottom faces horizontal. Which one of the following graphs best describes the gauge pressure *p* on the bottom of this block as a function of time *t* if the block just enters the water at time *t* = 0 s?

2

10) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always10)

keeping the top and bottom faces horizontal. Which one of the following graphs best describes the absolute (total) pressure *p* on the bottom of this block as a function of time *t* if the block just enters the water at time *t* = 0 s?

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

11) If atmospheric pressure increases by an amount*p*, which of the following statements about the11)pressure in a lake is true? (There could be more than one correct choice.) A) The absolute (total) pressure increases, but by an amount less than *p*. B) The gauge pressure does not change. C) The gauge pressure increases by *p*. D) The absolute (total) pressure increases by*p*. E) The absolute (total) pressure does not change. 12) A closed cubical chamber resting on the floor contains oil and a piston. If you push down on the12)piston hard enough to increase the pressure just below the piston by an amount *p*, which of the following statements is correct? (There could be more than one correct choice.)

- A) The pressure everywhere in the oil will increase by
*p*. - B) The pressure at the top of the oil will increase by less than
*p*. - C) The increase in the force on the top of the chamber will be the same as the increase in the force on the bottom of the chamber.
- D) The pressure at the bottom of the oil will increase by more than
*p*. - E) The pressure on the sides of the chamber will not increase.

3

13)The water pressure to an apartment is increased by the water company. The water enters the13) apartment through an entrance valve at the front of the apartment. Where will the increase in the static water pressure be greatest when no water is flowing in the system? A) at a faucet close to the entrance valve B) at a faucet far from the entrance valve C) There will be no increase in the pressure at the faucets. D) It will be the same at all faucets. 14)A waiter fills your water glass with ice water (containing many ice cubes) such that the liquid14) water is perfectly level with the rim of the glass. As the ice melts, A) the liquid-water level remains flush with the rim of the glass. B) the liquid-water level decreases. C) the liquid water level rises, causing water to run down the outside of the glass. 15)A spherical ball of lead (density 11.3 g/cm3) is placed in a tub of mercury (density 13.6 g/cm3).15) Which answer best describes the result?

- The lead will sink to the bottom of the mercury.
- The lead ball will float with its top exactly even with the surface of the mercury.
- The lead ball will float with about 83% of its volume above the surface of the mercury.
- The lead ball will float with about 17% of its volume above the surface of the mercury.

16)A wooden block contains some nails so that its density is exactly equal to that of water. If it is16) placed in a tank of water and released from rest when it is completely submerged, it will A) rise to the surface. B) remain where it is released. C) sink to the bottom. 17)A boat loaded with rocks is floating in a swimming pool. If the rocks are thrown into the pool, the17) water level in the pool, after the rocks have settled to the bottom, A) stays the same.B) rises.C) falls. 18)Salt water has greater density than fresh water. A boat floats in both fresh water and in salt water.18) Where is the buoyant force greater on the boat?

- in salt water
- in fresh water
- The buoyant force is the same in both cases.

19)Salt water is denser than fresh water. A ship floats in both fresh water and salt water. Compared19) to the fresh water, the volume of water displaced in the salt water is A) less. B) the same. C) more. D) Cannot be determined because we do not know the volume of the ship. 20)A steel ball sinks in water but floats in a pool of mercury, which is much denser than water.20) Where is the buoyant force on the ball greater? A) It is the same in both cases.

- B) floating on the mercury
- C) submerged in the water
- D) It cannot be determined from the information given.

4

21) A 10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is21)much denser than aluminum. Which one has the greater buoyant force on it? A) the lead B) Both have the same buoyant force. C) the aluminum D) It cannot be determined without knowing their volumes. 22) A piece of iron rests on top of a piece of wood floating in a bathtub. If the iron is removed from the22)wood, and kept out of the water, what happens to the water level in the tub? A) It goes up. B) It does not change. C) It goes down. D) It is impossible to determine from the information given. 23) A piece of wood is floating in a bathtub. A second piece of wood sits on top of the first piece, and23)does not touch the water. If the top piece is taken off and placed in the water, what happens to the water level in the tub?

- It does not change.
- It goes up.
- It goes down.
- It cannot be determined without knowing the volumes of the two pieces of wood.

24) As a rock sinks deeper and deeper into water of constant density, what happens to the buoyant24)

force on it if it started above the surface of the water?

- A) The buoyant force remains constant.
- B) The buoyant force first increases and then remains constant.
- C) The buoyant force keeps increasing steadily.
- D) The buoyant force steadily decreases.

5

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

25) A cubical block of stone is lowered at a steady rate into the ocean by a crane, always25)

keeping the top and bottom faces horizontal. Which one of the following graphs best describes the buoyant force *B* on this block as a function of time *t* if the block just enters the water at time *t* = 0 s?

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

26) A 50-cm3 block of wood is floating on water, and a 50-cm3 chunk of iron is totally submerged in26)the water. Which one has the greater buoyant force on it? A) Both have the same buoyant force. B) the wood C) the iron D) It cannot be determined without knowing their densities. 27) When you blow some air above a paper strip, the paper rises. This happens because27)A) the air above the paper moves faster and the pressure is lower. B) the air above the paper moves slower and the pressure is higher. C) the air above the paper moves slower and the pressure is lower.

- D) the air above the paper moves faster and the pressure remains constant.
- E) the air above the paper moves faster and the pressure is higher.

6

28)Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is28) the water pressure greatest? A) at point A B) at point B C) It is the same at both A and B. 29)Two horizontal pipes are the same length, but pipe B has twice the diameter of pipe A. Water29) undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe A is *Q* =*V*, what is the flow rate in pipe B? *t* A) 4*Q*B) 2*Q*C) 8*Q*D) *Q* 2E) 16*Q* 30)Two horizontal pipes have the same diameter, but pipe B is twice as long as pipe A. Water30) undergoes viscous flow in both pipes, subject to the same pressure difference across the lengths of the pipes. If the flow rate in pipe B is *Q* = *V*what is the flow rate in pipe A? *t* A) 8*Q*B) *Q* 2C) 4*Q*D) 2*Q*E) 16*Q* 31)A plastic block of dimensions 2.00 cm × 3.00 cm × 4.00 cm has a mass of 30.0 g. What is its density?31) A) 1.60 g/cm3B) 0.80 g/cm3 C) 1.20 g/cm3D) 1.25 g/cm3 32)A compressed gas with a total mass of 107 kg is stored in a spherical container having a radius of32) 0.521 m. What is the density of the compressed gas? A) 161 kg/m3B) 134 kg/m3 C) 110 kg/m3D) 181 kg/m3 33)The density of material at the center of a neutron star is approximately 1.00 *×* 1018 kg/m3. What is33) the mass of a cube of this material that is 1.76 microns on each side. (One micron is equal to 1.00 *×* 10–6 m.) A) 5.45 kgB) 6.70 kg C) 6.16 kg D) 4.74 kg 34)Under standard conditions, the density of air is 1.29 kg/m3. What is the mass of the air inside a34) room measuring 4.0 m × 3.0 m × 2.0 m? A) 3.1 kgB) 1.9 kgC) 0.32 kgD) 19 kgE) 31 kg 35)A round coin has a diameter of 19.55 mm, a thickness of 1.55 mm, and a mass of 2.50 g. What is its35) density?

- 5 × 103 kg/m3
- 34 × 103 kg/m3
- 68 × 103 kg/m3
- 86 × 10–4 kg/m3
- 37 × 103 kg/m3

7

36)A 1938 nickel has a diameter of 21.21 mm, a thickness of 1.95 mm, and weighs 0.04905 N. What is36) its density? A) 1.37 × 10–4 kg/m3 B) 7.26 × 103 kg/m3 C) 3.63 × 103 kg/m3 D) 1.82 × 103 kg/m3 E) 19.3 × 103 kg/m3 37)How many grams of ethanol (density 0.80 g/cm3) should be added to 5.0 g of chloroform (density37) 1.5 g/cm3) if the resulting mixture is to have a density of 1.2 g/cm3? Assume that the fluids do not change their volumes when they are mixed. A) 1.6 gB) 2.4 gC) 4.4 gD) 2.0 gE) 1.8 g 38)A 100-kg person sits on a 5-kg bicycle. The total weight is borne equally by the two wheels of the38) bicycle. The tires are 2.0 cm wide and are inflated to a gauge pressure of 8.0 × 105 Pa. What length of each tire is in contact with the ground? A) 2.4 cmB) 1.6 cmC) 6.4 cmD) 1.8 cmE) 3.2 cm 39)The weight of a 1200-kg car is supported equally by the four tires, which are inflated to the same39) gauge pressure. What gauge pressure is required so the area of contact of each tire with the road is 100 cm2? A) 2.9 × 105 PaB) 12 × 105 Pa C) 2.9 × 104 PaD) 12 × 104 Pa 40)One of the dangers of tornados and hurricanes is the rapid drop in air pressure that is associated40) with such storms. Assume that the air pressure inside of a sealed house is 1.02 atm when a hurricane hits. The hurricane rapidly decreases the external air pressure to 0.910 atm. What net outward force is exerted on a square window of the house that is 2.03 m on each side? (1.00 atm = 1.01 *×* 105 Pa) A) 4.59 *×* 104 NB) 5.42 *×* 105 N C) 4.82 *×* 105 ND) 5.19 *×* 104 N 41)Calculate the pressure exerted on the ground due to the weight of a 79-kg person standing on one41) foot. if the bottom of the person’s foot is 13 cm wide and 28 cm long. A) 2.2 *×* 103 PaB) 5.3 *×* 104 Pa C) 2.1 *×* 104 PaD) 4.8 *×* 104 Pa 42)A brick weighs 50.0 N, and measures 30.0 cm × 10.0 cm × 4.00 cm. What is the *maximum*pressure42) it can exert on a horizontal surface due to its weight? A) 1.25 kPaB) 12.5 Pa C) 12.5 kPaD) 1.25 Pa 43)A person weighing 900 N is standing on snowshoes. Each snowshoe has area 2500 cm 2 and has43) negligible weight. What pressure does this person’s weight exert on the snow? A) 1800 N/m2B) 0.36 N/m2 C) 0.18 N/m2D) 3600 N/m2

8

44) A water tank is filled to a depth of 10 m, and the bottom of the tank is 20 m above ground. A44)

water-filled hose that is 2.0 cm in diameter extends from the bottom of the tank to the ground, but no water is flowing in this hose. The water pressure at ground level in the hose is closest to which of the following values? The density of water is 1000 kg/m3.

- 9
*×*105 N/m2 - 2 N/m2
- 0
*×*104 N/m2 - The question cannot be answered because the cross sectional area of the tank is needed.

45) The Aswan High Dam on the Nile River in Egypt is 111 m high. What is the gauge pressure in the45)water at the foot of the dam? The density of water is 1000 kg/m3. A) 1.09× 106 Pa B) 1.16× 106 Pa C) 1.11× 105 Pa D) 1.11× 102 Pa E) 1.09× 103 Pa 46) The deepest point of the Pacific Ocean is 11,033 m, in the Mariana Trench. What is the gauge46)pressure in the water at that point? The density of seawater is 1025 kg/m3. A) 1.11× 108 Pa B) 3.33× 108 Pa C) 8.88× 107 Pa D) 2.22× 108 Pa E) 5.55× 107 Pa 47) The Tonga Trench in the Pacific Ocean is 36,000 feet deep. Assuming that sea water has an47)average density of 1.04 g/cm3, calculate the absolute (total) pressure at the bottom of the trench in atmospheres. (1.00 in = 2.54 cm, 1.00 atm = 1.01 *×* 105 Pa) A) 1.1 *×* 108 atm B) 1.1 *×* 103 atm C) 1.1 *×* 105 atm D) 1.1 *×* 106 atm E) 2.1 atm 48) What force does the water exert (in addition to that due to atmospheric pressure) on a submarine48)window of radius 44.0 cm at a depth of 9400 m in sea water? The density of sea water is 1025 kg/m3. A) 5.74× 1011 N B) 5.74× 107 N C) 2.87× 107 N D) 1.83× 107 N E) 2.87× 1011 N

9

49)A cubical box 25.0 cm on each side is immersed in a fluid. The pressure at the top surface of the49) box is 109.40 kPa and the pressure on the bottom surface is 112.00 kPa. What is the density of the fluid?1000 kg/m3 A) B) 1060 kg/m3 C)1030 kg/m3 D)1120 kg/m3 E) 1090 kg/m3 50)A circular window 30 cm in diameter in a submarine can withstand a *net* maximum force of 5.20 ×50) 105 N without damage. What is the maximum depth in a fresh-water lake to which the submarine can go without damaging the window? The density of fresh water is 1000 kg/m 3. A)680 mB) 1200 mC) 740 mD) 750 m 51)A container has a vertical tube, whose inner radius is 24.00 mm, connected to it at its side, as51) shown in the figure. An unknown liquid reaches level A in the container and level B in the tube

–level A being 5.0 cm higher than level B. The liquid supports a 20-cm high column of oil, between levels B and C, whose density is 570 kg/m3. The mass of the oil is closest to

A) 1000B) 410C) 210D) 620E) 820 52) A container has a vertical tube, whose inner radius is 12.00 mm, connected to it at its side, as52)

shown in the figure. An unknown liquid reaches level A in the container and level B in the tube –level A being 5.0 cm higher than level B. The liquid supports a 20-cm high column of oil, between levels B and C, whose density is 320 kg/m3. The gauge pressure at level B is closest to

- A) 790 Pa B) 940 Pa C) 630 Pa D) 310 Pa E) 470 Pa

10

53) A container has a vertical tube, whose inner radius is 20.00 mm, connected to it at its side, as53)

shown in the figure. An unknown liquid reaches level A in the container and level B in the tube –level A being 5.0 cm higher than level B. The liquid supports a 20-cm high column of oil, between levels B and C, whose density is 900 kg/m3. The density of the unknown liquid is closest to

- 3300 kg/m3
- 3100 kg/m3
- 2800 kg/m3
- 3900 kg/m3
- 3600 kg/m3

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

54) As shown in the figure, a large open tank contains a layer of oil ( density 450 kg/m 3)54)

floating on top of a layer of water (density 1000 kg/m3) that is 3.0 m thick, as shown in the sketch. What must be the thickness of the oil layer if the gauge pressure at the bottom of the tank is to be 8.5 x 104 Pa?

55) A container consists of two vertical cylindrical columns of different diameter connected by 55) a narrow horizontal section, as shown in the figure. The open faces of the two columns are closed by very light plates that can move up and down without friction. The tube diameter

at *A* is 35.0 cm and at *B* it is 10.2 cm. This container is filled with oil of density 0.820 g/cm3. If a 125-kg object is placed on the larger plate at *A*, how much mass should be placed on the smaller plate at *B* to balance it?

11

56) A 12,000-N car is raised using a hydraulic lift, which consists of a U-tube with arms of unequal56)areas, filled with oil and capped at both ends with tight-fitting pistons. The wider arm of the U-tube has a radius of 18.0 cm and the narrower arm has a radius of 5.00 cm. The car rests on the piston on the wider arm of the U-tube. The pistons are initially at the same level. What is the initial force that must be applied to the smaller piston in order to start lifting the car? For purposes of this problem, neglect the weight of the pistons. A) 2.90 kNB) 727 NC) 926 ND) 3.33 kNE) 1.20 kN 57) A 12,000-N car is raised using a hydraulic lift, which consists of a U-tube with arms of unequal57)areas, filled with oil with a density of 800 kg/m3 and capped at both ends with tight-fitting pistons. The wider arm of the U-tube has a radius of 18.0 cm and the narrower arm has a radius of 5.00 cm. The car rests on the piston on the wider arm of the U-tube. The pistons are initially at the same level. What is the force that must be applied to the smaller piston in order to lift the car after it has been raised 1.20 m? For purposes of this problem, neglect the weight of the pistons. A) 1.20 kNB) 1.88 kNC) 1.96 kND) 3.67 kNE) 0.954 kN 58) A 500-N weight sits on the small piston of a hydraulic machine. The small piston has an area of58)2.0 cm2. If the large piston has an area of 40 cm2, how much weight can the large piston support? Assume the pistons each have negligible weight. A) 40000 NB) 25 NC) 10000 ND) 500 N 59) In a hydraulic garage lift, the small piston has a radius of 5.0 cm and the large piston has a radius59)of 15 cm. What force must be applied on the small piston in order to lift a car weighing 20,000 N on the large piston? Assume the pistons each have negligible weight. A) 6.7 × 103 NB) 2.9 × 103 NC) 5.0 × 103 ND) 2.2 × 103 N 60) A 13,000-N vehicle is to be lifted by a 25-cm diameter hydraulic piston. What force needs to be60)applied to a 5.0 cm diameter piston to accomplish this? Assume the pistons each have negligible weight. A) 520 NB) 5200 NC) 2600 N D) 260 N

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

61) The small piston of a hydraulic lift has a diameter of 8.0 cm, and its large piston has a61)

diameter of 40 cm. The lift raises a load of 15,000 N. Assume the pistons each have negligible weight.

(a) Determine the force that must be applied to the small piston.

(b) Determine the pressure applied to the fluid in the lift.

62)A block of metal weighs 40 N in air and 30 N in water. What is the buoyant force on the block due62) to the water? The density of water is 1000 kg/m 3. A) 40 NB) 70 NC) 10 N D) 30 N 63)If a ship has a mass of 10 million kilograms, what volume of fresh water must it displace in order63) to float? The density of water is 1000 kg/m3. A) 1012 m3B) 1010 m3C) 107 m3D) 104 m3E) 108 m3

12

64)An object has a volume of 4.0 m3 and weighs 40,000 N. What will its apparent weight be in water64) of density 1000 kg/m3? A) 800 NB) 40,000 N C) 9,800 ND) 39,200 N 65)A 4.0-kg cylinder of solid iron is supported by a string while submerged in water. What is the65) tension in the string? The density of iron is 7860 kg/m3 and that of water is 1000 kg/m3. A) 2.5 NB) 24 NC) 20 ND) 40 NE) 34 N 66)What buoyant force does a 0.60-kg solid gold crown experience when it is immersed in water? The66) density of gold is 19.3 × 103 kg/m3 and that of water is 1000 kg/m3. A) 3.0 × 10–2 NB) 3.0 × 10–4 N C) 0.30 ND) 3.0 × 10–5 N 67)A crane lifts a steel submarine of density 7800 kg/m3 and mass 20,000 kg. What is the tension in67) the lifting cable (a) when the submarine is submerged in water of density 1000 kg/m 3, and (b) when it is entirely out of the water? A) (a) 2.6 × 103 N (b) 2.0 × 105 N B) (a) 2.0 × 105 N (b) 2.6 × 103 N C) (a) 1.7 × 105 N (b) 2.0 × 105 N D) (a) 2.0 × 105 N (b) 1.7 × 105 N 68)An object weighs 7.84 N when it is in air and 6.86 N when it is immersed in water of density 100068) kg/m3. What is the density of the object? A) 8000 kg/m3B) 9000 kg/m3 C) 6000 kg/m3D) 7000 kg/m3 69)When a container of water is placed on a laboratory scale, the scale reads 120 g. Now a 20-g piece69) of copper (of density 8.9 g/cm3) is suspended from a thread and lowered into the water, not touching the bottom of the container. What will the scale now read? The density of water is 1.0 g/cm3. A) 140 gB) 138 g C) 120 gD) 122 g

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

70) A piece of aluminum with a mass of 1.0 kg and density of 2700 kg/m3 is suspended from a 70) light cord and then completely immersed in a container of water having density 1000

kg/m3.

- Determine the volume of the piece of aluminum.
- Determine the tension in the cord when the aluminum is immersed in the container of water.

71) A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 71)

kg/m3. What is its mass? A) 38 gB) 150 gC) 75 gD) 300 g

13

72)A rectangular box of negligible mass measures 5.0 m long, 1.0 m wide, and 0.50 m high. How72) many kilograms of mass can be loaded onto the box before it sinks in a lake having water of density 1000 kg/m3? A) 3.5 × 103 kgB) 0.50 × 103 kgC) 2.5 × 103 kgD) 1.5 × 103 kg 73)A 1.00-m3 object floats in water with 20.0% of its volume above the waterline. What does the73) object weigh out of the water? The density of water is 1000 kg/m3. A) 9,800 NB) 1,960 NC) 11,800 ND) 7,840 N 74)An object floats with half its volume beneath the surface of the water. The weight of the displaced74) water is 2000 N. What is the weight of the object? The density of water is 1000 kg/m3.

- 2000 N
- 4000 N
- 1000 N
- It cannot be determined because we do not know the volume of the object.

75)A solid object floats in water with three-fourths of its volume beneath the surface. What is the75) object’s density? The density of water is 1000 kg/m 3. A) 1333 kg/m3B) 1000 kg/m3C) 250 kg/m3D) 750 kg/m3 76)A 200-N object floats with three-fourths of its volume beneath the surface of the water. What is76) the buoyant force on the object? The density of water is 1000 kg/m3.

- 150 N
- 267 N
- 200 N
- 50 N
- It cannot be determined because we do not know the volume of the object.

77) A polar bear of mass 200 kg stands on an ice floe that is a uniform 1.0 m thick. What is the77)minimum area of the floe that will just support the bear in saltwater of density 1030 kg/m 3? The density of ice is 980 kg/m3. A) 4.0 m2B) 3.0 m2C) 1.0 m2D) 2.0 m2

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

78) A wooden raft has a mass of 55 kg. When empty it floats in water (density 1000 kg/m 3)78)

with 64% of its volume submerged. What maximum mass of sand can be put on the raft without sinking it?

79) A hollow steel ball of diameter 3.0 m just barely floats in water. What is the wall thickness of the79)ball? (*ρ* = 7.87 g/cm3,*ρ* = 1.00 g/cm3) Fewater A) 6.6 cm B) 79 cmC) 131 cmD) 37 cm

14

80)A 200-kg flat-bottomed boat floats in fresh water, which has a density of 1000 kg/m3. If the base80) of the boat is 1.42 m wide and 4.53 m long, to what depth is the bottom of the boat submerged when it carries three passengers whose total mass is 257 kg? A) 7.95 cmB) 7.10 cmC) 7.53 cmD) 8.52 cm 81)A 4.7-kg solid sphere, made of metal whose density is 4000 kg/m3, hangs by a light cord. When81) the sphere is immersed in water, what is the tension in the cord? The density of water is 1000 kg/m3. A) 46 NB) 35 NC) 52 ND) 40 NE) 58 N 82)A solid sphere of mass 8.6 kg, made of metal whose density is 3400 kg/m 3, hangs by a cord. When82) the sphere is immersed in a liquid of unknown density, the tension in the cord is 38 N. The density of the liquid is closest to which one of the following values?

- 1500 kg/m3
- 1700 kg/m3
- 1400 kg/m3
- 1600 kg/m3
- 1900 kg/m3

83)A barge is 10 m wide and 60 m long and has vertical sides. The bottom of the boat is 1.2 m below83) the water surface. What is the weight of the barge and its cargo, if it is floating in fresh water of density 1000 kg/m3? A) 3.5 MNB) 6.8 MNC) 6.4 MND) 9.5 MNE) 7.1 MN 84)A barge with vertical sides is 10 m wide and 60 m long and is floating in fresh water of density84) 1000 kg/m3. How much deeper into the water does the barge sink when 3.0 x 105 kg of coal are loaded on the barge? A) 75 cmB) 50 cmC) 1.5 mD) 1.0 mE) 25 cm 85)A hot air balloon along with its cargo has a mass of 4.0 x 105 kg, and it holds 7.0 x 105 m3 of hot85) air. It is floating at a constant height in air with a density of 1.29 kg/m3. What is the density of the hot air in the balloon?

- 86 kg/m3
- 4 kg/m3
- 57 kg/m3
- 43 kg/m3
- 72 kg/m3

86) A person who weighs 550 N empties her lungs as much as possible and is then completely86)

immersed in water of density 1000 kg/m3 while suspended from a harness. Her apparent weight is now 21.2 N. What is her density?

- A) 960 kg/m3
- B) 1030 kg/m3
- C) 1040 kg/m3
- D) 1050 kg/m3
- E) 56.1 kg/m3

15

87)The bathyscaphe *Trieste* consists of a thin-walled but very strong cylindrical hull, 15.2 m long and87) 3.66 m in diameter, filled with gasoline with a density of 880 kg/m3 to make it buoyant. If it is totally submerged in seawater with a density of 1025 kg/m 3 and neither rising nor sinking, what is the weight of the *Trieste* craft? A) 227 kNB) 527 kNC) 427 kND) 127 kNE) 327 kN 88)A cylinder, semicircular in cross-section, is 10 m long and 5.0 m in radius. It is completely88) submerged, with its flat bottom side horizontal and 8.0 m below the water surface, as shown in the

figure. What is the magnitude of the net force on the curved upper surface of the half-cylinder? Neglect atmospheric pressure.

- 0 × 106 N
- 0 × 106 N
- 5 × 106 N
- 5 × 106 N
- 0 × 106 N

89) A rectangular wooden block measures 10.0 cm *×* 4.00 cm *×* 2.00 cm. When the block is placed in89)water, it floats horizontally, with its bottom face 1.65 cm below the surface. What is the density of the wood? The density of water is 1.00 g/cm3. A)0.606 g/cm3 B) 1.21 g/cm3 C)0.350 g/cm3 D)0.825 g/cm3 E) 1.65 g/cm3 90) Consider a very small hole in the bottom of a tank that is 17.0 cm in diameter and filled with water90)to a height of 90.0 cm. Find the speed at which the water exits the tank through the hole. A)17.64 m/sB) 48.3 m/sC) 44.1 m/sD) 4.20 m/s 91) Water flowing through a cylindrical pipe suddenly comes to a section of pipe where the diameter91)decreases to 86% of its previous value. If the speed of the water in the larger section of the pipe was 32 m/s, what is its speed in this smaller section if the water behaves like an ideal incompressible fluid? A)37 m/sB) 28 m/sC) 43 m/sD) 24 m/s 92) A pump uses a piston of 15 cm diameter that moves at 2.0 cm/s as it pushes a fluid through a pipe.92)What is the speed of the fluid when it enters a portion of the pipe that is 3.0 mm in diameter? Treat the fluid as ideal and incompressible. A)50 cm/sB) 22 cm/sC) 6.0 cm/sD) 50 m/s

16

93)An incompressible ideal fluid flows steadily through a pipe that has a change in diameter. The93) fluid speed at a location where the pipe diameter is 8.0 cm is 1.28 m/s. What is the fluid speed at a location where the diameter has narrowed to 4.0 cm? A) 1.3 m/sB) 0.32 m/sC) 2.6 m/sD) 0.64 m/sE) 5.1 m/s 94)Fluid flows at 2.0 m/s through a pipe of diameter 3.0 cm. What is the volume flow rate of the fluid?94) A) 14 m3/s B) 57 m3/s C) 1.4 × 10-3 m3/s D) 5.7 × 10-3 m3/s 95)Ideal incompressible fluid flows through a 4.0-cm-diameter pipe at 1.0 m/s. There is a 2.0 cm95) diameter constriction in the line. What is the speed of the fluid in this constriction? A) 2.0 m/sB) 0.50 m/sC) 4.0 m/sD) 0.25 m/s 96)Water, which we can treat as ideal and incompressible, flows at 12 m/s in a horizontal pipe with a96) pressure of 3.0 × 104 Pa. If the pipe widens to twice its original radius, what is the pressure in the wider section? A) 9.8 × 104 PaB) 4.9 × 104 PaC) 3.0 × 104 PaD) 7.4 × 104 Pa 97)A hole of radius 1.0 mm forms in the bottom of a very large water storage tank that holds water to97) a depth of 15 m. At what volume rate will water flow out of the hole? A) 5.4 × 10–6 m3/s B) 5.4 × 10–5 m3/s C) 5.4 × 10–4 m3/s D) 5.4 × 10–7 m3/s 98)Ideal incompressible water flows through a horizontal pipe of cross-sectional area 10.0 cm2 at a98) pressure of 0.250 atm with a volume flow rate of 1.00 × 10–3 m3/s. At a valve, the effective cross-sectional area of the pipe is reduced to 5.00 cm 2. What is the pressure at the valve? A) 0.112 atmB) 0.157 atmC) 0.235 atmD) 0.200 atm 99)For a certain patient, the build-up of fatty tissue on the wall of an artery has decreased the arterial99) radius by 10%. By how much would the pressure provided by the heart have to be increased to maintain a constant volume of blood flow? Model the blood as an ideal incompressible fluid. A) 46%B) 52%C) 48%D) 54%

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

100) An ideal incompressible fluid flows at 0.252 m/s through a 44-mm diameter cylindrical100)

pipe. The pipe widens to a *square* cross sectional area that is 5.5 cm on a side. Assume steady flow throughout the system.

(a) What is the speed of the fluid through the square section of pipe?

(b) What is the flow rate in liters per minute?

101) Ideal incompressible water is flowing in a drainage channel of rectangular cross-section. At one101)point, the width of the channel is 12 m, the depth of water is 6.0 m, and the speed of the flow is 2.5 m/s. At a point downstream, the width has narrowed to 9.0 m, and the depth of water is 8.0 m. What is the speed of the flow at the second point? A) 4.0 m/sB) 3.5 m/sC) 3.0 m/sD) 2.0 m/sE) 2.5 m/s

17

102)Water is flowing in a drainage channel of rectangular cross-section. The width of the channel is 15102) m, the depth of water is 8.0 m, and the speed of the flow is 2.5 m/s. What is the mass flow rate of the water? The density of water is 1000 kg/m3. A) 3.0 × 105 kg/s B) 3.0 × 103 kg/s C) 2.0 × 103 kg/s D) 3.0 × 102 kg/s E) 2.0 × 105 kg/s 103)In a section of horizontal pipe with a diameter of 3.0 cm, the pressure is 100 kPa and water is103) flowing with a speed of 1.5 m/s. The pipe narrows to 2.0 cm. What is the pressure in the narrower region? Treat the water as an ideal incompressible fluid. A) 95 kPaB) 230 kPaC) 48 kPaD) 44 kPaE) 67 kPa 104)Water flows through a horizontal pipe of cross-sectional area 10.0 cm2 at a pressure of 0.250 atm104) with a flow rate is 1.00 L/s. At a valve, the effective cross-sectional area of the pipe is reduced to 5.00 cm2. What is the pressure at the valve? The density of water is 1000 kg/m 3, and treat it as an ideal incompressible fluid. A) 0.200 atmB) 7700 PaC) 0.157 atmD) 0.235 atmE) 0.110 atm 105)An ideal incompressible fluid flows at 12 m/s in a horizontal pipe. If the pipe widens to twice its105) original radius, what is the flow speed in the wider section? A) 6.0 m/sB) 12 m/sC) 3.0 m/s D) 4.0 m/s 106)Water flows out of a large reservoir through an open pipe, as shown in the figure. What is the speed106) of the water as it comes out of the pipe?

A) 16 m/sB) 13 m/sC) 14 m/sD) 9.9 m/sE) 8.9 m/s 107) Water flows out of a large reservoir through 5.0-cm diameter pipe. The pipe connects to a 3.0-cm107)diameter pipe that is open to the atmosphere, as shown in the figure. What is the speed of the water in the 5.0-cm pipe? Treat the water as an ideal incompressible fluid.

- A) 2.3 m/s B) 8.9 m/s C) 3.2 m/s D) 10 m/s E) 3.9 m/s

18

108) A pressurized cylindrical tank, 5.0 m in diameter, contains water that emerges from the pipe at108)

point C with a speed of 13 m/s as shown in the figure. Point A is 10 m above point B and point C is 3.0 m above point B. The area of the pipe at point B is 0.080 m 2 and the pipe narrows to an area of

0.040 m2 at point C. Assume that the water is an ideal fluid in laminar flow. The density of water is

1000 kg/m3 The mass flow rate in the pipe is closest to

A) 310 Kg/s.B) 520 Kg/s.C) 470 Kg/s.D) 420 Kg/s.E) 360 Kg/s. 109) A pressurized cylindrical tank, 5.0 m in diameter, contains water that emerges from the pipe at109)

point C with a speed of 84 m/s, as shown in the figure. Point A is 10 m above point B and point C is 3.0 m above point B. The area of the pipe at point B is 0.080 m 2 and the pipe narrows to an area of

0.070 m2 at point C. Assume that the water is an ideal fluid in laminar flow. The density of water is

3

- A) 210 mm/s. B) 250 mm/s. C) 340 mm/s. D) 160 mm/s. E) 300 mm/s.

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

110) As shown in the figure, water (density 1000 kg/m3) is flowing in a pipeline. At point 1 the110)

water speed is 5.90 m/s. Point 2 is 5.20 m above point 1. The cross -sectional area of the pipe is 0.0800 m2 at point 1 and 0.0200 m2 at point 2. What is the pressure *difference p*1 – *p*2 between points 1 and 2? Treat the water as an ideal incompressible fluid.

5.20 m

19

111) A large cylindrical water tank 11.5 m in diameter and 13.5 m tall is supported with its base 111)

8.75 m above the ground by a stand as shown in the figure. The water level in the tank is

10.6 m deep, and the density of the water in the tank is 1.00 g/cm3. A very small hole is formed at the base of the vertical wall of the tank, and water is squirting out of this hole horizontally. When this water hits the ground, how far has it traveled horizontally from the hole, assuming no air resistance?

112)Glycerin, with a viscosity of 1.5 N · s/m2, is flowing with an average speed of 1.2 m/s through a112) tube that has a radius of 5.0 mm and is 25 cm long. What is the drop in pressure over the length of this pipe? A) 72 kPaB) 46 kPaC) 130 kPaD) 76 kPaE) 140 kPa 113)Motor oil, with a viscosity of 0.25 N · s/m2, is flowing through a tube that has a radius of 3.0 mm113) and is 1.0 m long. The drop in pressure over the length of the tube is 200 kPa. What is the average speed of the oil? A) 1.2 m/sB) 0.90 m/sC) 1.1 m/sD) 0.80 m/sE) 1.0 m/s 114)Motor oil, with a viscosity of 0.25 N · s/m2, is flowing through a tube that has a radius of 5.0 mm114) and is 25 cm long. The drop in pressure is 300 kPa. What is the volume of oil flowing through the tube per second?

- 025 m3/s
- 0012 m3/s
- 7 m3/s
- 00038 m3/s
- 5 m3/s

20

115) A fluid is flowing with an average speed of 1.5 m/s through a tube that has a radius of 2.0 mm and 115) is 18 cm long. The drop in pressure is 967 Pa. What is the viscosity of the fluid?

- 0018 N · s/m2
- 028 N · s/m2
- 0056 N · s/m2
- 0034 N · s/m2
- 013 N · s/m2

21