# Quiz 12: Fluid Flow

Physics & Astronomy

Q 1Q 1

The human body prioritizes its oxygen supply via blood based on the relevance of the organ and metabolic demand. What is the correct order of priorities of these selected organs, ranked from the highest to the lowest?
A)heart, brain, kidneys, liver
B)brain, heart, liver, kidneys
C)brain and heart equal priority, kidneys, liver
D)brain, heart, kidneys and liver equal priority

Free

Multiple Choice

C

Q 2Q 2

Which of the following is a property of an ideal fluid?
A)viscosity
B)incompressibility
C)turbulent flow
D)density fluctuations

Free

Multiple Choice

B

Q 3Q 3

The continuity equation (ÄV/Ät = const) is a consequence of conservation of which of the following aspects?
A)energy
B)shape
C)mass
D)pressure

Free

Multiple Choice

C

Q 4Q 4

Which of these statements describes a flow rate?
A)change of volume with time
B)change of mass with time
C)change of density with time
D)change of velocity with time

Free

Multiple Choice

Q 5Q 5

Water flows through a pipe that widens out to double its original diameter. How does the speed of water change in the area with the wider cross-section?
A)The speed doubles.
B)The speed increases by four times.
C)The speed decreases by four times.
D)The speed decreases by two times.

Free

Multiple Choice

Q 6Q 6

A pipe is delivering water at a rate of 25 L per minute. The diameter of the pipe opening is 2.0 cm. What is the speed of water flow?
A)0.03 m/s
B)1.3 m/s
C)20 m/s
D)332 m/s

Free

Multiple Choice

Q 7Q 7

Blood flows through an artery that has a narrowing of its diameter by 15% due to clogging. How does the speed of blood change in the area with the constricted cross-section?
A)The speed increases by 1.38 times.
B)The speed decreases by 1.38 times.
C)The speed increases by 0.76 times.
D)The speed decreases by 0.76 times.

Free

Multiple Choice

Q 8Q 8

A fluid flows at a rate of 30 L per minute through a pipe that has a cross-sectional radius of 2 cm. How will the flow change in the part of the pipe where the radius is constricted to half of its value?
A)The flow decreases to 15 L per minute.
B)The flow increases to 60 L per minute.
C)The flow decreases to 120 L per minute.
D)The flow stays the same.

Free

Multiple Choice

Q 9Q 9

Bernoulli's equation is a consequence of conservation of which of the following?
A)energy
B)shape
C)mass
D)pressure

Free

Multiple Choice

Q 10Q 10

One of the terms in Bernoulli's equation is ½ ñv

^{2}. Which of these quantities does it represent? A)kinetic energy B)kinetic energy per unit volume C)kinetic energy change in time D)pressure per unit volumeFree

Multiple Choice

Q 11Q 11

Blood flows with a velocity of 0.22 m/s through an artery that has a narrowing of the diameter by 15% due to clogging. How does the pressure of the blood change in the area that has the constricted cross-section? The density of blood is ñ = 1060 kg/m

^{3}. A)The speed increases by 73 Pa. B)The speed decreases by 73 Pa. C)The speed increases by 22 Pa. D)The speed decreases by 22 Pa.Free

Multiple Choice

Q 12Q 12

Water flows at 3 m/s through a horizontal pipe where the pressure is 2.3 × 10

^{5}Pa. Where the pipe constricts to a quarter of its original area, what is the pressure? A)1.6 × 10^{5}Pa B)2.2 × 10^{5}Pa C)2.3 × 10^{5}Pa D)3.1 × 10^{5}PaFree

Multiple Choice

Q 13Q 13

How will the force that is required to slide microscope slides past each other change if we reduce the separation between slides by 100 times, while retaining the velocity?
A)The force would need to increase by 100 times.
B)The force would need to decrease by 100 times.
C)The force would need to increase by 10 times.
D)The force would need to decrease by 10 times.

Free

Multiple Choice

Q 14Q 14

Consider a viscous fluid flowing through a cylindrical tube. If we reduce the area of the cross-section by half, how will the flow rate change?
A)The flow rate will double.
B)The flow rate reduces by half.
C)The flow rate will increase by 4 times.
D)The flow rate will decrease by 4 times.

Free

Multiple Choice

Q 15Q 15

If two liquids with different viscosities flow through tubes with identical parameters, how do their flow rates differ?
A)The fluid with the higher coefficient of viscosity has a lower flow rate.
B)The fluid with the higher coefficient of viscosity has a higher flow rate.
C)Their flow rates are identical because the tubes are identical.
D)We need additional information to answer this, such as the densities of the two fluids.

Free

Multiple Choice

Q 16Q 16

The fluid flow rate is 1.1 L per minute, and the tube has a diameter of 4 mm and a length of 10 cm. What is the viscosity of the fluid if the pressure drops 5.3 Pa over the length of the tube?
A)5 Pa s
B)2 Pa s
C)0.2 Pa s
D)5 × 10

^{-2}Pa sFree

Multiple Choice

Q 17Q 17

Corn syrup flows through a tube with a radius of 2 cm and a length of 2 m, at a speed of 0.4 m/s. What is the pressure difference in the tube? (Viscosity of syrup is ç = 1.38 Pa s.)
A)22 kPa
B)2.2 Pa
C)2.2 × 10

^{-2}Pa D)8.8 × 10^{-4}PaFree

Multiple Choice

Q 18Q 18

Poiseuille's law for flow of a fluid through a tube relates flow rate, drop of pressure over the length of the tube, velocity of the fluid, and radius of the tube. In which of the following situations would there be no pressure drop?
A)if flow rate is constant
B)if viscosity is zero (ideal fluid)
C)in the case of laminar flow
D)if the velocity of the fluid is constant

Free

Multiple Choice

Q 19Q 19

A fluid is flowing through a tube with a diameter of 4 mm, a length of 40 cm, at a speed of 0.7 m/s. The pressure drop is 950 Pa. What is the viscosity of the fluid?
A)68 Ns/m

^{2}B)1.7 × 10^{-3}N s/m^{2}C)6.7 × 10^{-3}N s/m^{2}D)6.7 × 10^{-5}N s/m^{2}Free

Multiple Choice

Q 20Q 20

Which quantity is conserved when Ohm's law is applied to a blood vessel that has variable resistance along its length?
A)flow rate
B)pressure
C)speed
D)volume

Free

Multiple Choice

Q 21Q 21

When blood branches into two or more blood vessels (in parallel) with different resistances, and then recombines into a single blood vessel again, which quantity is conserved?
A)flow rate
B)pressure
C)speed
D)volume

Free

Multiple Choice

Q 22Q 22

Reynolds number (Re) is a parameter introduced to determine whether the flow of a fluid is laminar or turbulent. It is given as Re = ñvd/ç, where ñ is the density of the fluid, v is the average speed of the fluid, d is the diameter of the tube, and ç is the viscosity coefficient of a fluid. What is the unit for Reynolds number?
A)kg/m s
B)kg m/s
C)kg m

^{2}/s^{2}D)Re has no unitsFree

Multiple Choice

Q 23Q 23

The main purpose of the high pressure blood system in the human body is to supply organs with oxygen.

Free

True False

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True False

Q 25Q 25

Flow rate is calculated as the area of the cross-section of a pipe times the velocity of a fluid, and the change of volume of the fluid in time.

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True False

Q 26Q 26

The equation of continuity applies only to fluids flowing in tubes, not to free falling fluid.

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True False

Q 27Q 27

Bernoulli's equation states that an increase in the speed of an ideal fluid is accompanied by a drop in its pressure.

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True False

Q 28Q 28

An artery that is constricted due to accumulated plaque on the inner walls tends to stretch outward a little in a constricted part, due to blood flow.

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True False

Q 29Q 29

In a viscous fluid, the force needed to move two surfaces past each other increases as separation between the surfaces is reduced.

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True False

Q 30Q 30

When a tube does not change radius, the pressure of a fluid must remain constant throughout the tube.

Free

True False

Q 31Q 31

Narrowing the tube through which a viscous fluid flows to a third of its original radius will reduce the flow rate by a factor of 81.

Free

True False

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True False

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True False

Q 34Q 34

A higher number of blood cells affects the flow resistance of blood through blood vessels. Resistance varies as a function of pressure difference.

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True False

Q 35Q 35

The outer diameter of an aorta is d = 2.6 cm. The fraction of the total diameter attributed to the wall is 15%. If the speed of blood in the aorta is 0.22 m/s, what is the rate at which the heart is pumping blood into the aorta, in litres per minute?

Free

Short Answer

Q 36Q 36

If you hold two papers at the top and let them hang vertically, parallel to each other, and blow fast air between them, will the papers spread apart or stick together?

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Essay

Q 37Q 37

A pipe of 50 mm diameter is used to supply water from the first to the second floor. The pressure in the pipe is 5.0 atm, and the speed of the water is 2.5 m/s. On the second floor, 4.5 m above, the pipe has a diameter of 30 mm. What is the speed and pressure in the narrower pipe?

Free

Essay

Q 38Q 38

How is it possible for birds to fly without flapping their wings (glide)? Which principle is responsible for this ability? How does the shape of the wing allow for gliding?

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Essay

Q 39Q 39

Figure 12.1 The figure shows a Venturi meter: connected tubes filled with an ideal fluid. The upper figure shows the fluid at rest, with the fluid shown by shading at the same height in a W-pipe. The lower figure shows moving fluid and uneven heights in a W-pipe.
-Explain why the fluid, as shown by shading in Fig. 12.1, rises in the middle branch of the W-pipe when the fluid above it flows in the direction shown by the arrow. Which law explains this phenomenon?

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Essay

Q 40Q 40

Arteriosclerosis is a constriction of the aorta due to plaque accumulated on the inner walls. An aneurysm is a widening of the aorta due to a weakening of the wall. In which of these two deformations will pressure on the walls increase, and in which will pressure decrease so much that it could close the aorta?

Free

Essay

Q 41Q 41

What is the thickness of a honey (viscosity ç = 8 Pa s) between two 10-cm-diameter parallel plates so that a force of 5 N is needed to pull the plates past each other at a speed of 0.1 m/s?

Free

Essay

Q 42Q 42

Figure 12.2 The figure shows pressures in vertical tubes due to flow of (a) an ideal fluid and (b) a real fluid.
-How does the real fluid differ from the ideal fluid? Which law(s) show(s) that Fig. 12.2(a) applies to the ideal fluid? Which law explains the gradual drop of pressures in the vertical tubes in Fig. 12.2(b)?

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Essay

Q 43Q 43

Figure 12.3 The figure shows pressures in vertical tubes due to flow of (a) real fluid through a tube of uniform cross-section, and (b) real fluid through a tube of uneven cross-section.
-Which law or physical principle explains the gradual drop of pressures in vertical tubes in Fig. 12.3(a), and why is the height in the middle vertical tube lower than in the others?

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Essay

Q 44Q 44

Figure 12.4 The figure shows flow of fluid through pipe A, branching into two identical pipes B and C with radii equal to half the radius of A, which reunite into a single pipe D.
-What fraction of the fluid from pipe A flows through pipe B in Fig. 12.4?

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Essay

Q 45Q 45

Figure 12.4 The figure shows flow of fluid through pipe A, branching into two identical pipes B and C with radii equal to half the radius of A, which reunite into a single pipe D.
-In Fig. 12.4, pipe A has a radius of 2 cm, and pipes B and C are each 6.0 m long. Glycerine, with a coefficient of viscosity 1.5 N s/m

^{2}, flows through the pipes at 30.0 cm/s. What is the drop in pressure that results from branching into two pipes?Free

Essay

Q 46Q 46

Figure 12.5 The figure shows volume flow rate of two different fluids.
-Describe the difference in characteristics of the two fluids (1 and 2) for which the flow rate versus pressure differences curves are given in Fig. 12.5. Which of the two can represent the flow rate of blood?

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Essay

Q 47Q 47

Figure 12.5 The figure shows volume flow rate of two different fluids.
-Analyze curve (2) in Fig. 12.5, which describes a volume flow rate of blood as a function of the pressure difference along the blood vessel. How could an allergy that would cause widening of blood vessels lower the speed of blood, leading to anaphylactic shock?

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Essay