Deck 10: Thermal Physics: Part A

Question 1

A reading of a tire gauge tells you that the gauge pressure in a tire is 34 lb/in​².What is the absolute pressure in the tire? Assume that atmospheric pressure is 14 lb/in​².

A) 20 lb/in​²
B) 62 lb/in​²
C) 48 lb/in​²
D) You can't be sure since you may have nitrogen-filled tires.

Answer 1

48 lb/in​²

Question 2

A ping-pong ball has an average density of 0.140 g/cm³ and a diameter of 3.80 cm.What force would be required to keep the ball completely submerged under water?

A) 0.484 N
B) 0.242 N
C) 0.516 N
D) 0.258 N

Answer 2

0.242 N

Question 3

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 0.40 atm?

A) 120,000 N
B) 12,000 N
C) 1200 N
D) 120 N

Answer 3

120,000 N

Question 4

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 0.050-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) 940 N
C) 3000 N
D) 15,000 N

Question 5

A stonecutter's chisel has an edge area of 0.40 cm².If the chisel is struck with a force of 45 N,what is the pressure exerted on the stone?

A) 1.1 × 10⁶ Pa
B) 1.1 × 10⁵ Pa
C) 5.5 × 10⁴ Pa
D) 1.1 × 10³ Pa

Question 6

At the altitude h the atmospheric pressure is half the pressure at sea level.Let
Equal the atmospheric pressure at sea level.What is the atmospheric pressure at an altitude 2h?

A) 0,since this is at twice the altitude where the pressure halves.
B) 0.37

C) 0.25

D) The answer is not given.

Question 7

A solid object is made of two materials,one material having density of 2000 kg/m³ and the other having density of 8000 kg/m³.If the object contains equal volumes of the materials,what is its average density?

A) 3000 kg/m³
B) 3200 kg/m³
C) 5000 kg/m³
D) more information is needed

Question 8

A piece of aluminum has density 2.70 g/cm³ and mass 834g.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) 633 g
C) 588 g
D) 190 g

Question 9

The Greenland ice sheet can be one km thick.Estimate the pressure underneath the ice where it is 0.80 km deep.(The density of ice is 918 kg/m³. )

A) 9.0 × 10⁵ Pa (9 atm)
B) 2.5 × 10⁶ Pa (25 atm)
C) 7.2 × 10⁶ Pa (72 atm)
D) 9.0 × 10⁶ Pa (90 atm)

Question 10

A block of wood has density 0.50 g/cm³ and mass 2250g.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) 3000 cm³
B) 2250 cm³
C) 1500 cm³
D) 1000 cm³

Question 11

A syringe has an inside radius of its barrel of 0.50 cm and at the opening at the end of the needle the radius is 1.0 mm.If a force F is applied to the plunger,what is the force produced at the opening of the needle?

A) 5F
B) 25F
C) F/5
D) F/25

Question 12

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.Dam #2 is twice as high and three 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) 24
B) 12
C) 6
D) 3

Question 13

A cube of wood of density 0.64 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) 3.6 cm
C) 2.2 cm
D) 6.4 cm

Question 14

By what factor is the total pressure greater at a depth of 650 m in water than at the surface where the 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) 64
D) 19

Question 15

A piece of aluminum has density 2.70 g/cm³ and mass 834g.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) 1125 cm³

Question 16

How deep under the surface of a lake would the pressure be triple that at the surface? (1 atm = 1.01 × 10⁵ Pa)

A) 1.00 m
B) 9.80 m
C) 10.3 m
D) 20.6 m

Question 17

A U-tube is partially filled with water and then an immiscible liquid is added to the right side.The top of the liquid is a distance h₁ above the level of interface between the liquid and water.On the left side of the tube the top of the water is a distance h₂ above the liquid-water interface on the right side.What is the density of the liquid in terms of the density of water
? Note that h₂ < h₁.

A)

B)

C)

D)

Question 18

If the column of mercury in a barometer stands at 69.4 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

Question 19

A solid object is made of two materials,one material having density of 2000 kg/m³ and the other having density of 6000 kg/m³.If the object contains equal masses of the materials,what is its average density?

A) 3000 kg/m³
B) 3200 kg/m³
C) 5000 kg/m³
D) more information is needed

Question 20

What volume of water is displaced by a submerged 16-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) 1.5 × 10−³ m³
C) 9.9 × 10³ m³
D) 5.9 × 10−³ m³

Question 21

The bottom of a flat-bottomed aluminum boat has an area of 4.0 m²,and the boat's mass is 120 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

Question 22

Water (density = 1 × 10³ kg/m³)flows at 16 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

Question 23

An ideal fluid,of density 0.90 × 10³ kg/m³,flows at 12 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 a radius of 1.5 cm.Find the speed of flow in the second pipe.

A) 54 m/s
B) 1.3 m/s
C) 0.67 m/s
D) 0.33 m/s

Question 24

A balloon of negligible mass is filled with 300 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) 150 kg
B) 300 kg
C) 333 kg
D) 444 kg

Question 25

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 6.43 kg.What is the density of the rock? (water density = 1000 kg/m³)

A) 1.40 × 10³ kg/m³
B) 3.50 × 10³ kg/m³
C) 1.84 × 10³ kg/m³
D) 1.58 × 10³ kg/m³

Question 26

Water (density = 1 × 10³ kg/m³)flows at 10 m/s through a pipe with radius 0.040 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) 0.045 m
B) 0.034 m
C) 0.015 m
D) 0.012 m

Question 27

A block of wood has a density of 650 kg/m³.When placed in water,what percent of the volume of the wood is above the surface?

A) 0,the block sinks.
B) 30%
C) 35%
D) 65%

Question 28

An ideal fluid flows through a pipe made of two sections with diameters of 1.0 and 2.0 inches,respectively.The speed of the fluid flow through the 2.0-inch section will be what factor times that through the 1.0-inch section?

A) 1/4
B) 1/2
C) 8
D) 4

Question 29

Water pressurized to 4 × 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

Question 30

The flow rate of blood through the average human aorta,of radius 0.95 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

Question 31

A fountain sends water to a height of 50 m.What must be the pressurization (above atmospheric)of the underground water system? (1 atm = 10⁵ N/m²)

A) 1 atm
B) 4.9 atm
C) 7.2 atm
D) 9.8 atm

Question 32

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 440 g,what volume would be necessary to prove that it is pure gold?

A) 31.1 cm³
B) 114 × 10³ cm³
C) 22.8 cm³
D) 1.81 × 10−² cm³

Question 33

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 2.0 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

Question 34

How much air must be pushed downward at 60.0 m/s to keep an 800-kg helicopter aloft?

A) 131 kg/s
B) 196 kg/s
C) 294 kg/s
D) 392 kg/s

Question 35

Water comes down the spillway of a dam from an initial vertical height of 100 m.What is the highest possible speed of the water at the end of the spillway?

A) 15 m/s
B) 44 m/s
C) 58 m/s
D) 1370 m/s

Question 36

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 0.080 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) 25 m/s
D) 0.99 m/s

Question 37

The flow rate of a liquid through a 2.0-cm radius pipe is 0.016 m³/s.The average fluid speed in the pipe is:

A) 0.64 m/s.
B) 13 m/s.
C) 0.040 m/s.
D) 6.4 m/s.

Question 38

The bottom of a flat-bottomed aluminum boat has area = 4.0 m² and mass = 120 kg.If two fishermen and their fishing gear with total mass of 240 kg are placed in the boat,how much lower will the boat ride in the water? (water density = 1.0 × 10³ kg/m³)

A) 0.15 m
B) 0.090 m
C) 0.075 m
D) 0.060 m

Question 39

A hole is poked through the metal side of a drum holding water.The hole is 28 cm below the water surface.What is the initial speed of outflow?

A) 1.9 m/s
B) 2.3 m/s
C) 3.2 m/s
D) 3.5 m/s

Question 40

An ideal fluid,of density 0.85 × 10³ kg/m³,flows at 0.50 kg/s through a pipe of radius 0.010 m.What is the fluid speed?

A) 0.95 m/s
B) 1.9 m/s
C) 3.0 m/s
D) 0.94 m/s

Question 41

A Boeing-737 airliner has a mass of 30,000 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) 1960 Pa
B) 2940 Pa
C) 7840 Pa
D) 15,700 Pa

Question 42

The SI units for viscosity are N·s/m².Another commonly used unit for viscosity is the poise,where 10 poise = 1 N·s/m².The poise is a fairly large unit,and it is more common to use the centipoise.Which of the following is equal to the centipoise?

A) 10−³ N·s/m²
B) 10−² N·s/m²
C) 10−¹ N·s/m²
D) 10² N·s/m²

Question 43

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 15 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) 4.4 × 10−⁵ m/s
D) 8.8 × 10−⁵ m/s

Question 44

A centrifuge rotates at 100 rev/s (i.e. ,628 rad/s).If the test tube places the suspension at 10 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 × 10³
B) 64
C) 800
D) 4.0 × 10⁴

Question 45

Water is being sprayed from a nozzle at the end of a garden hose of diameter 2.0 cm.If the nozzle has an opening of diameter 0.50 cm,and if the water leaves the nozzle at a speed of 15 m/s,what is the speed of the water inside the hose?

A) 0.63 m/s
B) 0.94 m/s
C) 2.5 m/s
D) also 10 m/s

Question 46

A fluid is drawn up through a tube as shown in the figure.If the height difference from the top of the tank to the bottom of the siphon is H = 1.1 m,then what is the outflow speed? Assume the pressure is the same at the top of the tank and at the siphon outlet.
​

A) 3.3 m/s
B) 21.6 m/s
C) 4.6 m/s
D) 5.4 m/s

Question 47

The equation of continuity applied to an incompressible ideal fluid flowing through a pipe of varying diameter is based on what of the following being conserved for the fluid in the pipe?

A) its kinetic energy
B) its momentum
C) its flow rate
D) its potential energy

Question 48

The fluid to which Bernoulli's equation is applied is based on what being conserved for the fluid?

A) its momentum
B) its potential energy
C) its kinetic energy
D) its total mechanical energy

Question 49

How much power is theoretically available from a mass flow of 1000 kg/s of water that falls a vertical distance of 50 m?

A) 980 kW
B) 98 kW
C) 4900 W
D) 490 kW

Question 50

A fluid has a density of 1040 kg/m³.If it rises to a height of 1.8 cm in a 2.0-mm diameter capillary tube,what is the surface tension of the liquid?

A) 0.046 N/m
B) 0.056 N/m
C) 0.092 N/m
D) 0.11 N/m

Question 51

It takes 2.0 minutes to fill a gas tank with 60 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? (1000 liters = one cubic meter)

A) 0.27 m/s
B) 1.1 m/s
C) 1.6 m/s
D) 64 m/s

Question 52

Water is sent from a fire hose at 40 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) 20 m

Question 53

Spherical particles of density 3.0 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 radius of the largest particles still in suspension at that time?

A) 4.5 × 10−⁶ m
B) 9.0 × 10−⁶ m
C) 2.6 × 10−⁶ m
D) 5.6 × 10−⁶ m

Question 54

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 4.3 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

Question 55

A pipe of diameter 4 cm is replaced by one of the same length but of diameter 5 cm.If the pressure difference between the ends of the pipe remains the same,by what factor is the rate of flow of a viscous liquid through it changed?

A) 5.1
B) 3.4
C) 2.4
D) 1.5

Question 56

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 4.0 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) 150 Pa