Deck 15: Fluids

Question 1

Substance A has a density of 3 g/cm³ and substance B has a density of 4 g/cm³.In order to obtain equal masses of these two substances,what must be the ratio of the volume of A to the volume of B?

A) =

B) =

C) =

D) =

E) =

Answer 1

=

Question 2

A 10-kg piece of aluminum sits at the bottom of a lake,right next to a 10-kg piece of lead,which is much denser than aluminum.Which one has the greater buoyant force on it?

A)the aluminum
B)the lead
C)Both have the same buoyant force.
D)It cannot be determined without knowing their volumes.

Answer 2

the aluminum

Question 3

If atmospheric pressure increases by an amount Δp,which of the following statements about the pressure in a lake is true? (There could be more than one correct choice. )

A)The absolute (total)pressure does not change.
B)The absolute (total)pressure increases,but by an amount less than Δp.
C)The absolute (total)pressure increases by Δp.
D)The gauge pressure increases by Δp.
E)The gauge pressure does not change.

Answer 3

The absolute (total)pressure increases by Δp.
The gauge pressure does not change.

Question 4

Salt water is denser than fresh water.A ship floats in both fresh water and salt water.Compared to the fresh water,the volume of water displaced in the salt water is

A)more.
B)less.
C)the same.
D)Cannot be determined because we do not know the volume of the ship.

Question 5

The water pressure to an apartment is increased by the water company.The water enters the 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)It will be the same at all faucets.
D)There will be no increase in the pressure at the faucets.

Question 6

An air bubble underwater has the same pressure as that of the surrounding water.As the air bubble rises toward the surface (and its temperature remains constant),the volume of the air bubble

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

Question 7

As shown in the figure,fluid fills a container having several sections.At which of the indicated points is the pressure greatest?

A)A
B)B
C)C
D)D
E)The pressure is the same at each of the labeled points.

Question 8

When a heavy metal block is supported by a cylindrical vertical post of radius R,it exerts a force F on the post.If the diameter of the post is increased to 2R,what force does the block now exert on the post?

A)F/4
B)F/2
C)F/
D)F
E)2F

Question 9

Salt water has greater density than fresh water.A boat floats in both fresh water and in salt water.Where is the buoyant force greater on the boat?

A)in salt water
B)in fresh water
C)The buoyant force is the same in both cases.

Question 10

Consider a brick that is totally immersed in water,with the long edge of the brick vertical.The pressure on the brick is

A)the same on all surfaces of the brick.
B)greatest on the face with largest area.
C)greatest on the top of the brick.
D)greatest on the sides of the brick.
E)greatest on the bottom of the brick.

Question 11

A boat loaded with rocks is floating in a swimming pool.If the rocks are thrown into the pool,the water level in the pool,after the rocks have settled to the bottom,

A)rises.
B)falls.
C)stays the same.

Question 12

A steel ball sinks in water but floats in a pool of mercury,which is much denser than water.Where is the buoyant force on the ball greater?

A)floating on the mercury
B)submerged in the water
C)It is the same in both cases.
D)It cannot be determined from the information given.

Question 13

When a box rests on a round sheet of wood on the ground,it exerts an average pressure p on the 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)4p
B)2p
C)p
D)p/2
E)p/4

Question 14

A waiter fills your water glass with ice water (containing many ice cubes)such that the liquid 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 rises,causing water to run down the outside of the glass.
C)the liquid-water level decreases.

Question 15

A closed cubical chamber resting on the floor contains oil and a piston.If you push down on the piston hard enough to increase the pressure just below the piston by an amount Δp,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 Δp.
B)The pressure at the bottom of the oil will increase by more than Δp.
C)The pressure at the top of the oil will increase by less than Δp.
D)The pressure on the sides of the chamber will not increase.
E)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.

Question 16

A wooden block contains some nails so that its density is exactly equal to that of water.If it is placed in a tank of water and released from rest when it is completely submerged,it will

A)rise to the surface.
B)sink to the bottom.
C)remain where it is released.

Question 17

A piece of iron rests on top of a piece of wood floating in a bathtub.If the iron is removed from the wood,and kept out of the water,what happens to the water level in the tub?

A)It goes up.
B)It goes down.
C)It does not change.
D)It is impossible to determine from the information given.

Question 18

A hollow sphere of negligible mass and radius R is completely filled with a liquid so that its density is ρ.You now enlarge the sphere so its radius is 2R and completely fill it with the same liquid.What is the density of the enlarged sphere?

A)8 ρ
B)4 ρ
C)ρ/2
D)ρ
E)ρ/8

Question 19

A styrofoam sphere of radius R has a density ρ.You now carefully compress the sphere so its radius is R/2.What is the density of the compressed sphere?

A)2 ρ
B)4 ρ
C)ρ
D)ρ
E)8 ρ

Question 20

A spherical ball of lead (density 11.3 g/cm³)is placed in a tub of mercury (density 13.6 g/cm³).Which answer best describes the result?

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

Question 21

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?

A)0.80 g/cm³
B)1.20 g/cm³
C)1.25 g/cm³
D)1.60 g/cm³

Question 22

Calculate the pressure exerted on the ground due to the weight of
Person standing on one foot.if the bottom of the person's foot is
Wide and
Long.

A)2.1 × 10⁴ Pa
B)2.2 × 10³ Pa
C)4.8 × 10⁴ Pa
D)5.3 × 10⁴ Pa

Question 23

A 50-cm³ block of wood is floating on water,and a 50-cm³ chunk of iron is totally submerged in the water.Which one has the greater buoyant force on it?

A)the wood
B)the iron
C)Both have the same buoyant force.
D)It cannot be determined without knowing their densities.

Question 24

A piece of wood is floating in a bathtub.A second piece of wood sits on top of the first piece,and 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?

A)It goes up.
B)It goes down.
C)It does not change.
D)It cannot be determined without knowing the volumes of the two pieces of wood.

Question 25

Under standard conditions,the density of air is 1.29 kg/m³.What is the mass of the air inside a room measuring 4.0 m × 3.0 m × 2.0 m?

A)0.32 kg
B)3.1 kg
C)31 kg
D)1.9 kg
E)19 kg

Question 26

A brick weighs 50.0 N,and measures 30.0 cm × 10.0 cm × 4.00 cm.What is the maximum pressure it can exert on a horizontal surface due to its weight?

A)1.25 Pa
B)12.5 Pa
C)1.25 kPa
D)12.5 kPa

Question 27

Water flows through a pipe.The diameter of the pipe at point B is larger than at point A.Where is the water pressure greatest?

A)at point A
B)at point B
C)It is the same at both A and B.

Question 28

A 1938 nickel has a diameter of 21.21 mm,a thickness of 1.95 mm,and weighs 0.04905 N.What is its density?

A)1.37 × 10^-4 kg/m³
B)1.82 × 10³ kg/m³
C)19.3 × 10³ kg/m³
D)3.63 × 10³ kg/m³
E)7.26 × 10³ kg/m³

Question 29

A compressed gas with a total mass of
Is stored in a spherical container having a radius of 0.521 m.What is the density of the compressed gas?

A)181 kg/m³
B)110 kg/m³
C)134 kg/m³
D)161 kg/m³

Question 30

One of the dangers of tornados and hurricanes is the rapid drop in air pressure that is associated 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
On each side? (1.00 atm = 1.01 × 10⁵ Pa)

A)4.59 × 10⁴ N
B)5.19 × 10⁴ N
C)4.82 × 10⁵ N
D)5.42 × 10⁵ N

Question 31

How many grams of ethanol (density 0.80 g/cm³)should be added to 5.0 g of chloroform (density 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)2.0 g
B)2.4 g
C)1.8 g
D)4.4 g
E)1.6 g

Question 32

Two horizontal pipes have the same diameter,but pipe B is twice as long as pipe A.Water 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 =
What is the flow rate in pipe A?

A)2Q
B)4Q
C)8Q
D)16Q
E)Q

Question 33

When you blow some air above a paper strip,the paper rises.This happens because

A)the air above the paper moves faster and the pressure is higher.
B)the air above the paper moves faster and the pressure is lower.
C)the air above the paper moves faster and the pressure remains constant.
D)the air above the paper moves slower and the pressure is higher.
E)the air above the paper moves slower and the pressure is lower.

Question 34

The density of material at the center of a neutron star is approximately 1.00 × 10¹⁸ kg/m³.What is the mass of a cube of this material that is
On each side.(One micron is equal to 1.00 × 10^-6 m. )

A)5.45 kg
B)4.74 kg
C)6.16 kg
D)6.70 kg

Question 35

Two horizontal pipes are the same length,but pipe B has twice the diameter of pipe A.Water 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 =
,what is the flow rate in pipe B?

A)2Q
B)4Q
C)8Q
D)16Q
E)Q

Question 36

A person weighing 900 N is standing on snowshoes.Each snowshoe has area 2500 cm² and has negligible weight.What pressure does this person's weight exert on the snow?

A)0.18 N/m²
B)0.36 N/m²
C)1800 N/m²
D)3600 N/m²

Question 37

As a rock sinks deeper and deeper into water of constant density,what happens to the buoyant force on it if it started above the surface of the water?

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

Question 38

A 100-kg person sits on a 5-kg bicycle.The total weight is borne equally by the two wheels of the 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)1.6 cm
B)1.8 cm
C)3.2 cm
D)2.4 cm
E)6.4 cm

Question 39

The weight of a 1200-kg car is supported equally by the four tires,which are inflated to the same gauge pressure.What gauge pressure is required so the area of contact of each tire with the road is 100 cm²?

A)12 × 10⁵ Pa
B)12 × 10⁴ Pa
C)2.9 × 10⁵ Pa
D)2.9 × 10⁴ Pa

Question 40

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 its density?

A)5.37 × 10³ kg/m³
B)21.5 × 10³ kg/m³
C)1.34 × 10³ kg/m³
D)2.68 × 10³ kg/m³
E)1.86 × 10^-4 kg/m³

Question 41

A 4.0-kg cylinder of solid iron is supported by a string while submerged in water.What is the tension in the string? The density of iron is 7860 kg/m³ and that of water is 1000 kg/m³.

A)2.5 N
B)20 N
C)24 N
D)34 N
E)40 N

Question 42

The deepest point of the Pacific Ocean is 11,033 m,in the Mariana Trench.What is the gauge pressure in the water at that point? The density of seawater is 1025 kg/m³.

A)5.55 × 10⁷ Pa
B)8.88 × 10⁷ Pa
C)1.11 × 10⁸ Pa
D)2.22 × 10⁸ Pa
E)3.33 × 10⁸ Pa

Question 43

The Tonga Trench in the Pacific Ocean is 36,000 feet deep.Assuming that sea water has an 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 × 10^{5 Pa)}

A)1.1 × 10³ atm
B)1.1 × 10⁸ atm
C)1.1 × 10⁵ atm
D)1.1 × 10⁶ atm
E)2.1 atm

Question 44

What force does the water exert (in addition to that due to atmospheric pressure)on a submarine window of radius 44.0 cm at a depth of 9,400 m in sea water? The density of sea water is 1025 kg/m³.

A)5.74 × 10⁷ _N
B)5.74 × 10¹¹ _N
C)2.87 × 10¹¹ _N
D)1.83 × 10⁷ _N
E)2.87 × 10⁷ _N

Question 45

A 12,000-N car is raised using a hydraulic lift,which consists of a U-tube with arms of unequal 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)0.954 kN
B)1.88 kN
C)1.96 kN
D)3.67 kN
E)1.20 kN

Question 46

A 12,000-N car is raised using a hydraulic lift,which consists of a U-tube with arms of unequal 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)727 N
B)926 N
C)2.90 kN
D)3.33 kN
E)1.20 kN

Question 47

A 500-N weight sits on the small piston of a hydraulic machine.The small piston has an area of 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)25 N
B)500 N
C)10000 N
D)40000 N

Question 48

What buoyant force does a 0.60-kg solid gold crown experience when it is immersed in water? The density of gold is 19.3 × 10³ kg/m³ and that of water is 1000 kg/m³.

A)3.0 × 10^-5 N
B)3.0 × 10^-4 N
C)3.0 × 10^-2 N
D)0.30 N

Question 49

In a hydraulic garage lift,the small piston has a radius of 5.0 cm and the large piston has a radius 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 N
B)5.0 × 10³ N
C)2.9 × 10³ N
D)2.2 × 10³ N

Question 50

A container has a vertical tube,whose inner radius is 12.00 mm,connected to it at its side,as 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
The gauge pressure at level B is closest to

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

Question 51

An object has a volume of 4.0 m³ and weighs 40,000 N.What will its apparent weight be in water of density 1000 kg/m³?

A)40,000 N
B)39,200 N
C)9,800 N
D)800 N

Question 52

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

A)3.9 × 10⁵ N/m²
B)2.0 × 10⁴ N/m²
C)9.2 N/m²
D)The question cannot be answered because the cross sectional area of the tank is needed.

Question 53

A container has a vertical tube,whose inner radius is 20.00 mm,connected to it at its side,as 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
The density of the unknown liquid is closest to

A)3,600 kg/ .
B)3,900 kg/ .
C)2,800 kg/ .
D)3,100 kg/ .
E)3,300 kg/ .

Question 54

A container has a vertical tube,whose inner radius is 24.00 mm,connected to it at its side,as 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
The mass of the oil is closest to

A)210.
B)410.
C)620.
D)820.
E)1,000.

Question 55

A block of metal weighs 40 N in air and 30 N in water.What is the buoyant force on the block due to the water? The density of water is 1000 kg/m³.

A)10 N
B)30 N
C)40 N
D)70 N

Question 56

A 13,000-N vehicle is to be lifted by a 25-cm diameter hydraulic piston.What force needs to be applied to a 5.0 cm diameter piston to accomplish this? Assume the pistons each have negligible weight.

A)260 N
B)520 N
C)2600 N
D)5200 N

Question 57

The Aswan High Dam on the Nile River in Egypt is 111 m high.What is the gauge pressure in the 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)1.09 × 10³ Pa
D)1.11 × 10⁵ Pa
E)1.11 × 10² Pa

Question 58

A cubical box 25.0 cm on each side is immersed in a fluid.The pressure at the top surface of the box is 109.40 kPa and the pressure on the bottom surface is 112.00 kPa.What is the density of the fluid?

A)1000 kg/m³
B)1030 kg/m³
C)1060 kg/m³
D)1090 kg/m³
E)1120 kg/m³

Question 59

A circular window 30 cm in diameter in a submarine can withstand a net maximum force of 5.20 × 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/m³.

A)680 m
B)740 m
C)1200 m
D)750 m

Question 60

If a ship has a mass of 10 million kilograms,what volume of fresh water must it displace in order to float? The density of water is 1000 kg/m³.

A)10¹⁰ m³
B)10¹² m³
C)10⁴ m³
D)10⁷ m³
E)10⁸ m³

Question 61

When a container of water is placed on a laboratory scale,the scale reads 120 g.Now a 20-g piece 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)120 g
B)122 g
C)138 g
D)140 g

Question 62

A 4.7-kg solid sphere,made of metal whose density is 4,000 kg/ m³. hangs by a light cord.When the sphere is immersed in water,what is the tension in the cord? The density of water is 1000 kg/m³.

A)35 N
B)40 N
C)46 N
D)52 N
E)58 N

Question 63

A solid object floats in water with three-fourths of its volume beneath the surface.What is the object's density? The density of water is 1000 kg/m³.

A)1333 kg/m³
B)1000 kg/m³
C)750 kg/m³
D)250 kg/m³

Question 64

A hot air balloon along with its cargo has a mass of 4.0 × 10⁵ kg,and it holds 7.0 × 10⁵ m³ of hot 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?

A)1.4 kg/m³
B)0.72 kg/m³
C)0.57 kg/m³
D)0.86 kg/m³
E)0.43 kg/m³

Question 65

A barge is 10 m wide and 60 m long and has vertical sides.The bottom of the boat is 1.2 m below 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 MN
B)6.4 MN
C)6.8 MN
D)7.1 MN
E)9.5 MN

Question 66

A person who weighs 550 N empties her lungs as much as possible and is then completely 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)1050 kg/m³
B)1040 kg/m³
C)1030 kg/m³
D)960 kg/m³
E)56.1 kg/m³

Question 67

An object weighs 7.84 N when it is in air and 6.86 N when it is immersed in water of density 1000 kg/m³.What is the density of the object?

A)6000 kg/m³
B)7000 kg/m³
C)8000 kg/m³
D)9000 kg/m³

Question 68

A cylindrical rod of length 12 cm and diameter 2.0 cm will just barely float in water of density 1000 kg/m³.What is its mass?

A)38 g
B)75 g
C)150 g
D)300 g

Question 69

A rectangular wooden block measures 10.0 cm × 4.00 cm × 2.00 cm.When the block is placed in 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)0.825 g/cm³
B)1.21 g/cm³
C)1.65 g/cm³
D)0.606 g/cm³
E)0.350 g/cm³

Question 70

A rectangular box of negligible mass measures 5.0 m long,1.0 m wide,and 0.50 m high.How many kilograms of mass can be loaded onto the box before it sinks in a lake having water of density 1000 kg/m³?

A)0.50 × 10³ kg
B)1.5 × 10³ kg
C)2.5 × 10³ kg
D)3.5 × 10³ kg

Question 71

A barge with vertical sides is 10 m wide and 60 m long and is floating in fresh water of density 1000 kg/m³.How much deeper into the water does the barge sink when 3.0 × 10⁵ kg of coal are loaded on the barge?

A)25 cm
B)50 cm
C)75 cm
D)1.0 m
E)1.5 m

Question 72

A solid sphere of mass 8.6 kg,made of metal whose density is 3,400 kg/
,hangs by a cord.When 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?

A)1,900 kg/
B)1,700 kg/
C)1,600 kg/
D)1,500 kg/
E)1,400 kg/

Question 73

A 200-N object floats with three-fourths of its volume beneath the surface of the water.What is the buoyant force on the object? The density of water is 1000 kg/m³.

A)50 N
B)150 N
C)200 N
D)267 N
E)It cannot be determined because we do not know the volume of the object.

Question 74

The bathyscaphe Trieste consists of a thin-walled but very strong cylindrical hull,15.2 m long and 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/m³ and neither rising nor sinking,what is the weight of the Trieste craft?

A)127 kN
B)227 kN
C)327 kN
D)427 kN
E)527 kN

Question 75

A crane lifts a steel submarine of density 7800 kg/m³ and mass 20,000 kg.What is the tension in the lifting cable (a)when the submarine is submerged in water of density 1000 kg/m³,and (b)when it is entirely out of the water?

A)(a)2.0 × 10⁵ N (b)1.7 × 10⁵ N
B)(a)1.7 × 10⁵ N (b)2.0 × 10⁵ N
C)(a)2.6 × 10³ N (b)2.0 × 10⁵ N
D)(a)2.0 × 10⁵ N (b)2.6 × 10³ N

Question 76

A 1.00-m³ object floats in water with 20.0% of its volume above the waterline.What does the object weigh out of the water? The density of water is 1000 kg/m³.

A)1,960 N
B)7,840 N
C)9,800 N
D)11,800 N

Question 77

An object floats with half its volume beneath the surface of the water.The weight of the displaced water is 2000 N.What is the weight of the object? The density of water is 1000 kg/m³.

A)1000 N
B)2000 N
C)4000 N
D)It cannot be determined because we do not know the volume of the object.

Question 78

A polar bear of mass 200 kg stands on an ice floe that is a uniform 1.0 m thick.What is the minimum area of the floe that will just support the bear in saltwater of density 1030 kg/m³? The density of ice is 980 kg/m³.

A)1.0 m²
B)2.0 m²
C)3.0 m²
D)4.0 m²

Question 79

A 200-kg flat-bottomed boat floats in fresh water,which has a density of 1000 kg/m³.If the base 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 257kg?

A)7.10 cm
B)7.53 cm
C)7.95 cm
D)8.52 cm

Question 80

A hollow steel ball of diameter 3.0 m just barely floats in water.What is the wall thickness of the ball? (ρ_Fe = 7.87 g/cm³,ρ_water = 1.00 g/cm³)

A)6.6 cm
B)37 cm
C)131 cm
D)79 cm