Deck 13: Solids and Fluids

Question 1

A 3.0-m long steel music wire has a radius of 0.04 mm.When the wire is under a tension of 100 N,how much does its length change?

A)0.10 m
B)0.27 m
C)0.30 m
D)0.47 m

Answer 1

0.30 m

Question 2

A cubic block of cherry wood with sides of 10.0 cm has a density of 800 kg/m³.The cubic block floats in water.What is the distance of the top surface of the block from the water level?

A)1.0 cm
B)2.0 cm
C)3.0 cm
D)4.0 cm
E)5.0 cm

Answer 2

2.0 cm

Question 3

A supertanker filled with oil has a total mass of 14.5 * 10⁸ kg.If the dimensions of the ship are those of a rectangular box 275 meters long,90 meters wide,and 60 meters high,determine how far the bottom of the ship is below sea level.( $\rho$ _sea = 1020 kg/m³)

A)60 m
B)57 m
C)50 m
D)It does not float,it sinks.
E)None are correct.

Answer 3

57 m

Question 4

At what depth in the ocean is the pressure 280.8 kPa? The density of seawater is 1030 kg/m³ and atmospheric pressure is 101.3 kPa.

A)27.8 m
B)17.8 m
C)9.80 m
D)1.00 m

Question 5

An object's true weight is 123 N.When it is completely submerged in water,its apparent weight is 82.0 N.If the density of water is 1000 kg/m³,then what is the density of the object?

A)333 kg/m³
B)1333 kg/m³
C)3000 kg/m³
D)4100 kg/m³

Question 6

A single 8 * 11.5 inch sheet of paper is placed horizontally on a table.What is the approximate mass of all the air directly above the paper?

A)9.81 kg
B)1.01 * 10⁵ kg
C)1350 kg
D)611 kg
E)14.7 kg

Question 7

A force of 39.2 N is exerted on the small piston of diameter 1.25 cm to support a 1600-kg car on the hydraulic lift shown.What gauge pressure produces this force?

A)1.6 * 10⁴ Pa
B)2.2 * 10⁴ Pa
C)3.2 * 10⁴ Pa
D)4.0 * 10⁴ Pa
E)5.0 * 10⁴ Pa

Question 8

A fountain sends water to a height of 150 meters.What is the difference between the pressure of the water system and the atmospheric pressure?

A)9.71 atm
B)12.1 atm
C)14.6 atm
D)17.0 atm
E)19.4 atm

Question 9

A supertanker filled with oil has a total mass of 12.5 * 10⁸ kg.If the dimensions of the ship are those of a rectangular box 300 meters long,60 meters wide,and 60 meters high,determine how far the bottom of the ship is below sea level.( $\rho$ _sea = 1020 kg/m³)

A)60 m
B)57 m
C)50 m
D)It does not float,it sinks.
E)None are correct.

Question 10

Water at ground level is moving at a speed of 1.20 m/sec in a pipe at a pressure of 850 kPa.The pipe goes up to the fourth floor of a building where its elevation is 12.5 meters above the ground and its radius is the same.The density of water is 1000 kg/ m³.What is the pressure of the water on the fourth floor?

A)425 kPa
B)525 kPa
C)727 kPa
D)827 kPa

Question 11

Salt water has greater density than fresh water.A boat floats in both fresh water and in salt water.The submerged volume of the boat in salt water is _____ that in fresh water.

A)equal to
B)smaller than
C)larger than
D)None are correct.

Question 12

A mass of 1000 kg is placed on top of a 2.000-m long,10.00-mm diameter vertical aluminum rod.If the bottom of the rod cannot move downward,what is the length of the rod when the mass is placed on top of it?

A)2.004 m
B)1.996 m
C)1.993 m
D)1.990 m
E)2.000 m

Question 13

The solid wood cylinder madder of oak with a uniform density of 750 kg/m³ is dropped in the ocean,which has a density 1027 kg/m³.The diameter of the cylinder is 0.540 m and its height is 0.240 m.Assuming that the flat ends of the cylinder are parallel to the surface of the water and that the water is calm,the top of the cylinder will

A)be 0.175 m above the water line.
B)be 0.123 m above the water line.
C)be 0.0647 m above the water line.
D)be 0.175 m below the water line.
E)sink to the ocean floor.

Question 14

A plastic cup,20.0 cm in height,is filled to the rim with water.A small hole is punctured in the cup at a height 12.00 cm above the bottom of the cup and is allowing water to spew out.What is the speed of the water as it exits the hole?

A)0.54 m/s
B)0.75 m/s
C)0.82 m/s
D)1.3 m/s
E)1.6 m/s

Question 15

A plastic cup,15.0 cm in height,is filled to the rim with water.A small hole is punctured in the cup at a height 9.00 cm above the bottom of the cup and is allowing water to spew out.At what distance does the water land from the bottom of the cup?

A)12.1 cm
B)13.6 cm
C)14.6 cm
D)15.8 cm
E)16.1 cm

Question 16

Find the minimum diameter of a nylon wire 50 m long that will stretch no more than 25 cm when a load of 90.0 kg is hung on the lower end.Assume that Y _nylon = 3.51 * 10⁸ N/m².

A)1.11 cm
B)0.253 cm
C)0.111 cm
D)2.53 cm
E)1.24 cm

Question 17

Icebergs have an average density of 920 kg/m³.Seawater has an average density of 1030 kg/m³.An iceberg floats in seawater.What percentage of the iceberg's volume is in the air above the surface of the seawater?

A)10.7%
B)12.0%
C)47.0%
D)50.0%

Question 18

A motorist pulls into a gas station and uses a pressure gauge to check one of the tires on her car.The gauge reads 301.3 kPa.What is the absolute pressure of the air in the tire? Atmospheric pressure is 101.3 kPa.

A)200.0 kPa
B)301.3 kPa
C)402.6 kPa
D)602.6 kPa

Question 19

A plastic cup,15.0 cm in height,is filled to the rim with water and is resting on a table.A small hole is punctured in the cup at a height 9.00 cm above the bottom of the cup and is allowing water to spew out.What is the speed of the water as it exits the hole?

A)1.08 m/s
B)1.99 m/s
C)1.72 m/s
D)1.65 m/s
E)1.33 m/s

Question 20

A plastic cup,15.0 cm in height,is filled to the rim with water and is resting on a table.A small hole is punctured in the cup at a height 9.00 cm above the bottom of the cup and is allowing water to spew out.What is the speed of the water when it strikes the table?

A)1.33 m/s
B)1.72 m/s
C)1.08 m/s
D)1.65 m/s
E)1.99 m/s

Question 21

A 6-cm cube of plastic floats in water with 1 cm of the cube above the water.What is the density of the cube?

A)1.0 g/cm³
B)0.8 g/cm³
C)1.2 g/cm³
D)0.5 g/cm³
E)0.6 g/cm³

Question 22

A beaker is filled with water to the rim.Gently placing a plastic toy duck in the beaker causes some of the water to spill out.The weight of the beaker with the plastic toy duck floating in it is

A)greater than what it was before placing the duck.
B)less than what it was before placing the duck.
C)same as what it was before placing the duck.
D)greater or less than what it was before placing the duck depending on the weight of the toy duck.

Question 23

A 3.14-m long steel cable with a cross-sectional area of 1.42 cm² is attached to a 894-kg car ( )that has fallen into a pond ( ).How much will the cable stretch as it pulls the car upward at a constant speed? Assume the car is pulled slowly enough to ignore the effects of resistance and ignore the weight of the steel cable.(Young's modulus for steel is 200 x 10⁹ N/m².)

A)8.5 * 10^-4 mm
B)9.5 * 10^-4 mm
C)0.31 mm
D)0.85 mm
E)0.95 mm

Question 24

The cylindrical container in figure has a radius of 1 m and contains motor oil with a density of 730 kg m^-3.Oil is seen to flow out of the 20-cm long,2-cm diameter tube at the bottom of the container.If 3.80 *10^-3 m³ of oil flows out of the tube in 29 seconds,what is the viscosity of the oil? Assume the change in the level of the oil in the reservoir over the time period is negligible.

A)0.30 Pa s
B)0.29 Pa s
C)0.54 Pa s
D)0.68 Pa s
E)0.47 Pa s

Question 25

In the figure,water flows in the pipe as shown.What does the top pressure gauge read?

A)25.6 kPa
B)31.5 kPa
C)84.5 kPa
D)63.4 kPa
E)100 kPa

Question 26

A 1.0-g balloon is filled with helium gas.When a mass of 4.0 g is attached to the balloon,it is seen to be static equilibrium in mid air.Assuming the balloon is spherical,what is its diameter?

A)20 cm
B)15 cm
C)25 cm
D)10 cm
E)40 cm

Question 27

The cylindrical container in figure has a radius of 1 m and contains motor oil with viscosity of 0.3 Pa s.Oil is seen to flow out of the 20-cm long,2-cm diameter tube at the bottom of the container.If 5.65 * 10^-3 m³ of oil to flow out of the tube in 29 seconds,what is the density of the oil? Assume the change in the level of the oil in the reservoir over the time period is negligible.

A)730 kg m^-3
B)610 kg m^-3
C)580 kg m^-3
D)670 kg m^-3
E)640 kg m^-3

Question 28

In 1964 the freighter Al Kuwait (mass 2.02 * 10⁶ kg)sank in Kuwait harbor.It was re-floated by filling its hull with polystyrene beads.If the density of sea water is 1025 kg/m³,the density of the beads was 28.0 kg/m³,and 30 million beads were required,what was the average volume of one of the beads? Ignore the buoyant force of the steel in the ship.

A)7.83 * 10^-5 m³
B)5.44 * 10^-5 m³
C)8.09 * 10^-5 m³
D)6.75 * 10^-5 m³
E)6.32 * 10^-5 m³

Question 29

The cylindrical container in figure has a radius of 1 m and contains motor oil with viscosity of 0.3 Pa s and a density of 670 kg m^-3.Oil is seen to flow out of the 20-cm long,2-cm diameter tube at the bottom of the container.How much oil flows out of the tube in a period of 10 s if the container is filled to a height of 0.5 m? We can assume that the change in the level of the reservoir over the period of 10 s is negligible.

A)5.65 * 10^-2 m³
B)8.35 * 10^-2 m³
C)2.15 * 10^-3 m³
D)5.65 * 10^-3 m³
E)1.45 * 10^-2 m³

Question 30

Water flows through a 10-cm diameter pipe at a rate of 3 L/s.What is the flow rate if the pipe narrows to 5 cm?

A)3 L/s
B)6 L/s
C)12 L/s
D)8 L/s
E)4 L/s

Question 31

How deeply would one have to dive into a pool of mercury (density = 13.59 g/cm³)to experience a pressure of 10 atm (1 atm = 1.01 * 10⁵ Pa)?

A)1.2 m
B)3.7 m
C)0.7 m
D)4.1 m
E)6.8 m

Question 32

In 1964 the freighter Al Kuwait (mass 2.02 * 10⁶ kg)sank in Kuwait harbor.It was re-floated by filling its hull with polystyrene beads.If the density of sea water is 1025 kg/m³,the density of the beads was 28.0 kg/m³,and 30 million beads were required,what was the average radius of one of the beads? Ignore the buoyant force of the steel in the ship.

A)2.53 cm
B)6.85 cm
C)1.68 cm
D)5.45 cm
E)9.45 cm

Question 33

A ping-pong ball has a mass of 2.70 g and has a radius of 20.0 mm.What is the magnitude of its acceleration when placed underneath the surface of a pond ( )and released? Ignore the effect of water resistance

A)0.305 m/s²
B)2.72 m/s²
C)26.7m/s²
D)30.9 m/s²
E)113 m/s²

Question 34

In the figure,water flows in the pipe as shown.What is the diameter of the top section,d?

A)1.5 cm
B)4.0 cm
C)3.5 cm
D)2.5 cm
E)3.0 cm

Question 35

Aluminum foil costs $3.88 for a 3.48 m² sheet that has a thickness of 0.013 mm.If the density of aluminum is 2700 kg/m³,what is the cost of one atom of aluminum? The atomic mass number for aluminum is 26.98.

A)$1.4 * 10^-24
B)$5.3 * 10^-24
C)$2.4 * 10^-23
D)$3.8 * 10^-23
E)$5.2 * 10^-23

Question 36

In 1964 the freighter Al Kuwait (mass 2.02 * 10⁶ kg)sank in Kuwait harbor.It was re-floated by filling its hull with polystyrene beads.If the density of sea water is 1025 kg/m³,the density of the beads was 28.0 kg/m³,and the average volume of the beads were 7.45 * 10^-5 m³,find how many beads were required.Ignore the buoyant force of the steel in the ship.

A)19.8 million
B)26.5 million
C)27.2 million
D)28.0 million
E)96.8 million

Question 37

The cylindrical container in figure has a radius of 1 m and contains motor oil with viscosity of 0.3 Pa s and a density of 670 kg m^-3.Oil is seen to flow out of the 20-cm long,2-cm diameter tube at the bottom of the container.How long will it take 5.65 * 10^-3 m³ of oil to flow out of the tube? Assume the change in the level of the oil in the reservoir over the time period is negligible.

A)10 seconds
B)14 seconds
C)21 seconds
D)19 seconds
E)26 seconds

Question 38

For climbing the Sawatch range of Rocky mountains you used a 50-m nylon rope of 10 mm diameter.You noticed the rope elongated by 1.50 m when it supported your 65-kg mass on one end.The Young's modulus of the rope material is

A)54 * 10⁶ N/m².
B)112 * 10⁶ N/m².
C)271 * 10⁶ N/m².
D)356 * 10⁶ N/m².
E)980 * 10⁶ N/m².

Question 39

In 1964 the freighter Al Kuwait (mass 2.02 * 10⁶ kg)sank in Kuwait harbor.It was re-floated by filling its hull with polystyrene beads.If the density of sea water is 1025 kg/m³,the average volume of the beads was 8.09 *10^-5 m³ and 25 million beads were required,what was the density of the beads? Ignore the buoyant force of the steel in the ship.

A)21.9 kg/m³
B)21.2 kg/m³
C)24.8 kg/m³
D)26.2 kg/m³
E)28.0 kg/m³

Question 40

Osteoporosis is a disease occurring especially in women after menopause in which the bones become very porous and as a result break easily with a fall or the application of even a small amount of force.Assume the breaking stress of a bone is 1.30 * 10⁷ N/m²,the magnitude of the maximum force a disease femur bone 3-cm in average diameter could withstand is

A)225 kN.
B)212 kN.
C)106 kN.
D)92 kN.
E)9.19 kN.

Question 41

How much greater is the pressure (in Pa)at a depth of 100 m in the ocean than at the surface? (specific gravity ocean water = 1.13)

A)1.2 * 10⁵
B)0.9 * 10⁵
C)1.1 * 10⁶
D)2.4 * 10⁶
E)1.2 * 10⁷

Question 42

Two wires of the same material are stretched by equal forces,but L₁ = 2L₂ and d₁ = 2d₂,where L and d are the lengths and diameters of the two wires.The ratio of the stresses stress₁/stress₂ is

A)1.
B)2.
C)4.
D)½.
E)¼.

Question 43

A piece of aluminum is 13 cm long and when subject to a compressional force of 540 N,compresses by 0.13 mm.What is its area in mm²? Young's modulus for Aluminum is 7.0 * 10¹⁰ Pa.

A)7.7
B)4.3 * 10³
C)0.123
D)0.95
E)1.6 * 10^-6

Question 44

If the radius of your head (treated as a cylinder)is 7.0 cm,what is the force exerted by air pressure on the top of your head? Assume standard pressure of 101.5 kPa.

A)150 N
B)520 N
C)660 N
D)1.6k N

Question 45

Two wires of the same material are stretched by equal forces,but L₁ = 2L₂ and d₁ = 2d₂,where L and d are the lengths and diameters of the two wires.The ratio of the change in lengths is

A)1.
B)2.
C)4.
D)½.
E)¼.

Question 46

What is the ratio in pressure at the closed bottom of an open,1.5-m tall tube of mercury (density 13.7 g/cm³)to that at the top? Assume the laboratory air pressure is 101.5 kPa.

A)0.34
B)0.83
C)1.2
D)2.0
E)3.0

Question 47

Your friend Zach can inhale to create a gauge pressure of -70 mm of Hg (density of Hg = 13.6 g/cm³).The height of water (density of water = 1 g/cm³)Zach can raise in a straw is

A)95.2 cm.
B)66.2 cm.
C)45.9 cm.
D)32.1 cm.
E)19.2 cm.

Question 48

A small cube of copper (density = 8930 kg/m³)is used to support a large cube of marble (density = 2560 kg/m³).The copper cube has sides of length 2.00 cm and is carefully placed on a flat,level table under the center of the cube of marble that has sides of length 30.0 cm.Given that the Young's modulus of copper is 110 GPa,by how much is the copper compressed?

A)2.0 * 10^-8 m
B)6.8 * 10^-8 m
C)3.1 * 10^-8 m
D)1.1 * 10^-6 m
E)3.6 * 10^-6 m

Question 49

A piston with a cross-sectional area of 30 cm² and a volume of 160 cm³ can be pressured to a maximum gauge pressure of 10 atmospheres.What is the maximum force that the piston can deliver?

A)3.0 * 10³ N
B)1.6 * 10⁴ N
C)1.6 * 10⁵ N
D)1.0 * 10⁶ N
E)3.0 * 10⁷ N

Question 50

Two wires of the same material are stretched by equal forces,but L₁ = 2L₂ and d₁ = 2d₂,where L and d are the lengths and diameters of the two wires.The ratio of the Young's modulii Y₁/Y₂ is

A)1.
B)2.
C)4.
D)½.
E)¼.

Question 51

A metal block with a mass of 4.0 kg is hanging from a string.The block is lowered into a full beaker of water,causing 1,000 cm³ of water to spill out of the beaker.What is the tension in the string while the block is completely underwater?

A)9.8 N
B)29 N
C)38 N
D)40 N
E)49 N

Question 52

During a recent thunderstorm the wind was blowing past your roof at 40 m/s (90 miles/hour).Assuming that the density of air is 1.20 kg/m³,the size of the roof is 10 m by 15 m,and the air under the roof was at rest,the net force experienced by the roof was

A)288 kN.
B)144 kN.
C)89 kN.
D)75 kN.
E)61 kN.

Question 53

Assuming that one exhales pure carbon dioxide (relative mass number approximately 44)what mass of carbon dioxide does an average person exhale in one year,assuming a breathing rate of 12 breaths per minute,and a volume of 0.50 liters per breath?

A)1.2 * 10⁴ kg
B)6.2 * 10³ kg
C)3.1 * 10³ kg
D)1.4 * 10² kg

Question 54

A cube is 10 cm on an edge is suspended in water.The pressure

A)is greatest on the bottom.
B)is greatest on the top.
C)is greatest on the sides.
D)is the same everywhere.
E)is the same on top and bottom but not the sides.

Question 55

If two objects,one of lead and the other of aluminum,weigh the same in water,then

A)they will weigh the same in alcohol.
B)they must have the same density.
C)the aluminum weight must have a lower volume than the lead weight.
D)they must have the same mass.
E)the aluminum weight will weigh more in alcohol than the lead weight does.

Question 56

If 5.2 N of force is required to hold a 24-cm diameter solid ball completely submerged in a vat of water,what is the density of the material out of which the ball is made?

A)0.28 g/cm³
B)0.93 g/cm³
C)0.98 g/cm³
D)0.99 g/cm³
E)1.1 g/cm³

Question 57

A 500-g cubic block of a composite material floats with 40% of its volume submerged in your swimming pool.The force you have to apply to fully submerge it in the water is

A)7.4 N.
B)9.8 N.
C)13.2 N.
D)19.4 N.
E)27.5 N.

Question 58

Assuming that one exhales pure carbon dioxide (relative mass number approximately 44),how many carbon dioxide molecules does one exhale in a single 0.50 liter breath?

A)1.3 * 10²²
B)2.6 * 10²²
C)3.0 * 10¹⁸
D)5.7 * 10²³.

Question 59

A solid object weighs 15.70 N in air.When it is suspended from a scale and submerged in water,the scale reads 5.30 N.Find the density of the object.(Use 1000.0 kg/m³ for the water density.)(in kg/m³)

A)6.18 * 10²
B)7.73 * 10²
C)9.66 * 10²
D)1.21 * 10³
E)1.51 * 10³

Question 60

A piece of cork (density = 0.33 g/cm³)with a mass of 10 g is held in place by a string attached to the bottom of the cork.If the cork is completely underwater in distilled water,what is the tension in the string?

A)0.1 N
B)0.2 N
C)0.3 N
D)98 N
E)297 N

Question 61

A beach ball of radius 30 cm is pushed under water.What force is required to keep the ball submerged?

A)113 kg
B)113 N
C)1.1·10⁷ N
D)1108 N
E)30 kg

Question 62

A very large wind turbine is used to extract power from the wind.The turbine has a diameter of 120 meters.What is the maximum power this turbine can extract from the wind.Assume a wind speed of 10 m/s and the density of air is 1.2 kg/m³.

A)4.02 MW
B)7.52 MW
C)3.40 MW
D)6.80 MW

Question 63

Which of the following statements is true?

A)If a piece of material sinks in both liquid A and liquid B,but requires a different amount of force to lift it when submerged in each one,its density must be less than the density of both liquids.
B)If a piece of material sinks in both liquid A and liquid B,but requires a different amount of force to lift it when submerged in each one,the two liquids must have different density.
C)As a scuba diver descends the pressure on her mask increases.However,it depends on whether she is looking up or down.
D)As a scuba diver descends the pressure on his mask increases.The pressure depends on how far above the bottom of the ocean he is.
E)A piece of iron is lowered to the bottom of the ocean where the pressure is 21 atmospheres.The density of the iron will increase by a factor of 21.

Question 64

The maximum pressure that can be obtained in your local mechanic's hydraulic pump is 2.0 * 10⁵ Pa.The piston has a mass of 1.8 * 10⁴ Kg and a radius R = 1.0 m,what is the largest mass (of a car)for which the pump will work?

A)2.2 * 10⁴ Kg
B)3.0 * 10⁴ Kg
C)3.8 * 10⁴ Kg
D)4.6 * 10⁴ Kg
E)7.4 * 10⁴ Kg

Question 65

A wind turbine is used to extract power from the wind.If the diameter of the turbine is doubled,the maximum power extracted from the wind will increase by a factor of

A)2
B)4
C)6
D)8
E)16

Question 66

A glass is initially filled with 155 cm³ water plus 85 cm³ of ice so that the water level is exactly at the rim of the glass,with some of the ice sticking out above the rim.After all of the ice has melted and turned into water,

A)the water level in the glass has decreased in such a way that you can add another 85 cm³ of water without the glass overflowing.
B)the water level in the glass has decreased in such a way that you can add another 12 cm³ of water without the glass overflowing.
C)the water level will remain at exactly the same level,and no water will flow over.
D)a total of 12 cm³ of the water will overflow.
E)a total of 85 cm³ of the water will overflow.

Question 67

A wind turbine is used to extract power from the wind.If the speed of the wind is doubled,the maximum power extracted from the wind will increase by a factor of

A)2
B)4
C)6
D)8
E)16

Question 68

Two pistons exert forces F₁ and F₂ on a fluid at points 1 and 2,producing pressures p₁ and p₂ over areas A₁ and A₂.If the pistons do not move under the influence of these forces,it then follows necessarily that

A)F₁ = F₂.
B)F₁ = (A₂/A₁)F₂.
C)F₁ = (A₁/A₂)F₂.
D)p₁ = (A₁/A₂)p₂.
E)A₁ = A₂.

Question 69

"16 castaways marooned in the South China Sea!" They construct a 50-kg raft made out of Pulau Tiga wood,which Rudy has determined its specific gravity to be 0.047.If each survivor has a mass 100 kg,what is the maximum number of survivors that can ride the raft without sinking? (Rich says that the density of sea water is 1.03 * 10³ kg/m³.)

A)10
B)12
C)14
D)all 16 castaways
E)None,the raft cannot float itself.

Question 70

What is the change in volume of a 1.00-m³ block of granite between the surface of the ocean and a 3.00 km depth? (Information that might be useful: The pressure at this depth is about 300 times atmospheric pressure.Atmospheric pressure is 1.013 * 10⁵ Pa.The bulk modulus of granite is 5.0 * 10¹⁰ Pa.)

A)-1.22 * 10^-6 m³
B)-6.1 * 10^-4 m³
C)1.22 * 10^-6 m³
D)4.3 * 10^-2 m³
E)2.5 * 10^-1 m³

Question 71

An object is completely submerged in oil with specific gravity 0.7.Which statement below is correct?

A)If the specific gravity of the object is greater that 1.0,it will rise.
B)If the specific gravity of the object is less than 0.7,a force downward is required to keep it submerged.
C)If the specific gravity of the object is greater that 0.7,it will float.
D)If the object is hanging from a spring scale,it will weigh more when in the oil than out.
E)If the object has specific gravity 1.0,it will float with 30% of its volume out of the oil.

Question 72

A large wind turbine is used to extract power a maximum power of 3.38 MW from the wind.What is the minimum diameter of the turbine which will meet this power requirement? Assume a wind speed of 10 m/s and the density of air is 1.2 kg/m³.

A)100 m
B)110 m
C)130 m
D)120 m

Question 73

A syringe with a plunger of diameter 1.6 cm is attached to a hypodermic needle with a diameter of 2.5 mm.What minimum force must be applied to the plunger to inject into a vein in which the pressure is 2265.9 Pa?

A)0.05 N
B)0.15 N
C)0.30 N
D)0.46 N
E)0.60 N

Question 74

What is the buoyant force on a 1.3 m³ helium balloon in air at standard conditions? The density of air is 1.3 kg/m³.

A)1.3 N
B)1.69 N
C)16.6 N
D)232 N
E)1690 N

Question 75

A women's high-heeled shoe has an area of 0.5 cm².Assuming that the woman wearing the shoe has a mass of 52 kg,and that all her weight momentarily rests on one heel,what is the pressure that the heel exerts on the floor?

A)10 Pa
B)52 Pa
C)510 Pa
D)10⁵ Pa
E)10⁷ Pa

Question 76

A particular steel cable used in the construction of a suspension bridge experiences a stress which stretches the cable by 0.3% of its manufactured length.Given that Young's modulus for steel is 2.0 * 10¹¹ Pa,find the value of this stress.

A)1.5 * 10¹⁰ Pa
B)2.5 * 10¹² Pa
C)3.0 * 10¹¹ Pa
D)1.0 * 10⁷ Pa
E)6.0 * 10⁸ Pa

Question 77

The Earth's atmosphere is composed (by volume)of 78.08% nitrogen (N₂),20.95% oxygen (O₂),0.93% argon (Ar),0.25% water vapor (H₂O),and traces of other gases,most importantly,carbon dioxide (CO₂).The CO₂ content of the atmosphere is currently around 0.039%.The average mass of a mole of the atmosphere is 28.96 g and the molar mass of carbon dioxide is 44 g.What is the total mass of CO₂ in the Earth's atmosphere?

A)2.05·10¹⁵ kg
B)3.11·10¹⁵ kg
C)4.86·10¹⁵ kg
D)7.97·10¹⁸ kg
E)5.25·10¹⁸ kg

Question 78

A 3.3-m long wire with a cross sectional area of 4.7 * 10^-5 m² is stretched 8.3 * 10^-4 m by a force of 234 N.What is Young's modulus for this material?

A)1.98 * 10¹⁰ N/m²
B)5.67 * 10¹² N/m²
C)9.81 * 10⁸ N/m²
D)4.55 * 10⁶ N/m²
E)3.21 * 10^-11 N/m²

Question 79

The Earth's atmosphere is composed nitrogen (N₂),oxygen (O₂),argon (Ar),water vapor (H₂O),and traces of other gases.There are 6.74·10¹⁶ kg of argon in earth's atmosphere.The average mass of a mole of the atmosphere is 28.96 g and the molar mass of argon is 40 g.What is the percentage,by volume of argon in the Earth's atmosphere?

A)0.79%
B)0.53%
C)0.88%
D)1.02%
E)0.93%

Question 80

Find the pressure difference (in N/m²)between the inside and outside of a window which looks into a swimming pool 12 m below the surface.(The density of water is 1000 kg/m³.)

A)12.1
B)3.42 * 10⁷
C)1.17 * 10⁵
D)5.67 * 10³
E)zero