Chapter 4 - Fluids
1 Pa = ____ N/m^2
1
A specific gravity of exactly _____ indicates that 100% of the object will be submerged but it will not sink
1
At specific gravity, water has a density of exactly ________g/cm^3.
1
Density of water is _____ g/cm^3 or ____ kg/m^3
1, 1000
1 atm = _____ Pa
1.013 x 10^5
A hydraulic system is designed to allow water levels to change depending on a force applied at the top of a tank. If a force, F1, of 4N is applied to a square, flexible cover where A1=16, and the area of A2=64, what force must be applied to A2 to keep the water level from changing?
16 N F1/A1=F2/A2
1.013x10^5 Pa = ______ mmHg = 760 torr = 1 atm
760
A tank with height y is filled with water to the top and is placed at a height z above the ground. Currently the water level is 3.0 meters above the ground. At the bottom of the tank, there is a hole where the water can flow out when needed. Which of the following would increase the flow rate? A. Increase the size of the hole B. Increase z C. Decrease the size of the hole to increase the velocity out of the hole D. Increase y and z without adding additional water
A. Increase the size of the hole
When the gauge pressure is doubled, what happens to the absolute pressure? A. It increases by a factor less than 2. B. It stays the same. C. It doubles. D. It is halved.
A. It increases by a factor less than 2.
__________ principle deals with the buoyancy of objects when placed in a fluid. It states that a body wholly or partially immersed in a fluid will be buoyed upwards by a force equal to the weight of the fluid that it displaces
Archimedes'
A water tower operator is interesting in increasing the pressure of a column of water that is applied to a piston. How should the speed of the water be changed to increase the pressure and the force? A. Increase the speed B. Decrease the speed C. Release water intermittently against the pipe D. The speed of the water will not change the pressure at the piston.
B. Decrease the speed At equal heights, speed and pressure of a fluid are inversely related.
According to your understanding of Bernoulli's principle and continuity equation, which of the following statements accurately describes the phenomenon of vascular flutter which occurs when an artery becomes constricted due to the accumulated plaque in its inner walls? A. Constriction in the blood vessel causes backup and the pressure to build before the narrowing. B. The constriction causes the pressure to drop and the vessel to collapse. C. The constriction will cause the blood to travel faster and the extra blood will create pressure after the narrowing. D. Constriction in the blood vessel causes the pressure to build up right at the narrowing.
B. The constriction causes the pressure to drop and the vessel to collapse.
A hydraulic lever is used to lift a heavy hospital bed, requiring an amount of work, W. When the same bed with a patient is lifted, the work required is doubled. How can the cross sectional area of the platform on which the bed is lifted be changed so that the pressure on the hydraulic lift remains constant? A. The cross sectional area must be halved. B. The cross sectional area must be doubled C. The cross sectional area must be divided by four D. The cross sectional area must remain constant.
B. The cross sectional area must be doubled
Which of the following scenarios most accurately represents Pascal's law? A. A person pushes the brake with a small area with a small force over a short distance to produce an equivalent force to stop the car. B. The volume displaced by piston 1 is equal to the volume displaced by piston 2 in a hydraulic lift. C. When a pregnant mother is riding in a car that crashes, the fluid surrounding the fetus will help to dissipate any force from the crash. D. When you push down on the stopper of a big water jug with 10 N, the same force of 10 N is transmitted undiminished to the larger bottom surface of the jug.
B. The volume displaced by piston 1 is equal to the volume displaced by piston 2 in a hydraulic lift.
Which of the following is NOT characteristic of a liquid with laminar flow? A. little lateral mixing B. presence of eddies C. low velocity D. high viscous forces
B. presence of eddies
Equation that states that the sum of the static pressure and dynamic pressure will be constant within a closed container for an incompressible fluid not experiencing viscous drag
Bernoulli's
_______ equation cannot be applied to turbulent flow systems
Bernoulli's
A gold crown recently acquired is suspected to be brass covered in gold. The crown weighs 25.0 N in air and has an apparent weight of 22.5 N in fresh water. Based on these results, which of the following conclusions is correct? (density of gold = 19,300 kg/m^3, density of brass= 8300-8700 kg/m^3 A. It is likely that the crown is made of half brass and half gold. B. It is likely that the crown is made of brass only. C. It is likely that the crown is made of brass covered in gold. D. It is likely that the crown is made of gold only.
C. It is likely that the crown is made of brass covered in gold. 25.0-22.5= 2.5N 2.5N= 1000 kg/m^3 x V x 10 m/s^2 = 2.5 x 10^-4 mass of the crown=25.0/10 = 2.5kg density of the crown = 2.5/2.5 x 10^-4 =10,000 kg/m^3
The speed of blood in the aorta is much higher than the speed of blood through a capillary bed. How can this be explained using the continuity equation, assuming that we are interested in average flow, and there is no net fluid loss? A, The aorta is located higher than the capillary bed B. The pressure in the aorta is the same as the pressure in the capillary bed. C. The cross sectional area of all the capillaries added together is much greater than the cross sectional area of the aorta D. The cross sectional area of a capillary is much smaller than the cross sectional area of the aorta
C. The cross sectional area of all the capillaries added together is much greater than the cross sectional area of the aorta
Which of the following data sets is sufficient to determine the linear speed through an area of a rigid pipe? A. The cross sectional area in another segment of the pipe and the cross sectional area in the region of interest B. The reynolds number, viscosity of the fluid, density, and diameter of the pipe C. The radius of the pipe, pressure gradient, viscosity and length of the pipe D. The absolute pressure and density
C. The radius of the pipe, pressure gradient, viscosity and length of the pipe
Q=v1A1=v2A2
Continuity equation
There is a 1-liter container filled with 500 milliliters of water placed on top of a scale displaying 80 pounds. When a metal cube is submerged tied to a string end into the container, which of the following statements accurately describes the result? A. The scale will remain at 80 pounds unless the cube touches the bottom of the bowl. B. The scale will remain at 80 pounds until the cube is floating on top of the water fully submerged. C. The cube's density must be provided to predict what will happen. D. The scale will register a weight greater than 80 pounds due to Newton's Third Law.
D. The scale will register a weight greater than 80 pounds due to Newton's Third Law.
On which of the following does the buoyant force on an object floating on the surface of a liquid most directly depend? A. mass of the liquid B. volume of the object C. viscosity of the liquid D. density of the liquid
D. density of the liquid F=p(fluid)v(displaced)g
SI Unit of Pressure
Pascal
SI Unit of pressure
Pascal
___________ Principle states that for incompressible fluids, a change in pressure will be transmitted undiminished to every portion of the fluid and to the walls of the containing vessels.
Pascal's
SI Unit of viscosity
Paxs
With laminar flow through a pipe or confined space, it is possible to calculate the rate of flow using _____ law
Poiseuille's
Nr
Reynold's number
________ pressure is the total pressure that is exerted on an object that is submerged in a fluid.
absolute
The attractive force that a molecule of the liquid feels toward the molecules of some other substance.
adhesion
When the critical speed is exceeded, the fluid demonstrates complex flow patterns, and laminar flow occurs only in the thin layer of fluid ____ to the wall, called the ____ layer
adjacent, boundary
Atmospheric pressure changes with _______
altitude
Gauge pressure is equal to the pressure exerted by a column of fluid plus the __________ pressure above the fluid, minus the ______ pressure
ambient, atmospheric
Gauge pressure is the amount of pressure in a closed space above and beyond the __________ pressure
atmospheric
________ pressure changes with altitude
atmospheric
Because all fluids have density, the volume of fluid displaced will correspond to a certain mass of fluid. The force, which is always directed upwards is called the _____ force
buoyant
The strong attractive forces between water pulls the surface of the liquid of water towards the _____, and establishes tension in the plane of the surface of the water.
center
The circulatory system is a ______ ___ that has a ______ flow rate due to valves, gravity, and physical properties of our vessels.
closed loop, constant
Attractive force that a molecule of liquid feels towards other molecules of the same liquid.
cohesion
Surface tension results from ______, which is the attractive force that a molecule of liquid feels towards other molecules of the same liquid.
cohesion
Bernoulli's equation is an expression of energy ________ for flowing fluids.
conservation
Bernoulli's formula is basically a statement of the _______ of energy. More energy dedicated towards fluid movement means less energy dedicated toward static fluid pressure
conservation
We can very clearly state, without any exceptions that the flow rate is ____ for a closed system and is independent of changes in cross-sectional area.
constant
In unobstructed fluid flow, turbulence can arise when the speed of the fluid exceeds a certain _______.
critical speed
Streamlines never ____ each other
cross
When the flow rate is constant, the linear speed of the fluid does change relative to the ______-_____ area
cross, sectional
Hydraulic machines generate output force by magnifying an input force by a factor equal to the ratio of the ____________ of the larger piston to that of the smaller piston.
cross-sectional area
p
density
To determine how much of a floating object lies below the surface, one must make comparisons of _____ or ____ ____
density, specific gravity
The weight of any given substance with a known density can be calculated by multiplying the substance's ______ by its ______ and the _______ due to gravity
density, volume, acceleration
Linear speed is a measure of the linear _________ of fluid particles in a given amount of time.
displacement
If the object is completely submerged and the volume of displaced fluid still does not exert a buoyant force equal to the weight of the object, the object will accelerate _____ and sink to the ____.
downward, bottom
Pressure associated with the movement of a fluid
dynamic pressure
Because viscosity is a measure of a fluid's internal resistance to flow, more viscous fluids lose more ____ while flowing.
energy
Pressure can be though as a ratio of ____ per cubic meter, or energy density
energy
Systems at higher pressure have a higher ________ ____ than systems at lower pressure
energy density
Despite the differences in flow rate and volume in the circulatory system, the blood volume entering the heart is always ____ to the blood volume leaving the heart
equal
For incompressible fluids, a change in pressure will be transmitted undiminished to _______ of the fluid and to the walls of the containing vessel
every portion
Q
flow rate
The product of linear speed and cross-sectional area is equal to the ______
flow rate
Fluids are characterized by their ability to ____ and ____ to the shapes of their containers.
flow, conform
Solids do not ____ and are ____ enough to retain a shape independent of their containers
flow, rigid
When atmospheric pressure is the only pressure above the fluid column, then gauge pressure equals the _____ pressure.
fluid
Study of fluids in motion
fluid dynamics
When using the buoyancy equation, always remember to use the density of the _____, and not the ____.
fluid, object
The Continuity equation arises from the conservation mass of ____
fluids
Pressure if a ratio of the ___ per unit _____
force, area
Difference between the absolute pressure inside the tire and the atmospheric pressure outside the tire.
gauge pressure
A _________, is when the liquid level is higher than the middle of the edges and occurs when the cohesive forces are ______ than the adhesive forces
greater
As blood flows away from the heart, each vessel has a progressively ___ resistance until the capillaries; however, the total resistance of the system decreases because the increased number of vessels are in parallel with each other.
higher
_______ systems take advantage of the near-incompressibility of liquids to generate mechanical advantage
hydraulic
Absolute pressure is also known as ____ pressure
hydrostatic
Study of fluids at rest and the forces and pressures associated with standing fluids
hydrostatics
Fluids with volumes that cannot be reduced by any significant degree through application of pressure are _____
incompressible
A significant amount of energy is dissipated from the system as a result of the _____ frictional forces in turbulent flow
increased
The pressure gradients created in the thorax by ________ and ____ also motivate blood flow.
inhalation, exhalation
Low-viscosity fluids have low ___________ ______ to flow and behave like ideal fluids. Assume conservation of energy in low-viscosity fluids with laminar flow
internal resistance
The relationship between the radius and pressure gradient is _____ exponential to the ___ power
inverse, fourth
SI Units for density
kg/m^3
The equation for dynamic pressure is essentially the formula for _________
kinetic energy
__________ flow is smooth and orderly, and is often modeled as layers of fluid that flow ____ to each other
laminar, parallel
When applying Pascal's principle, the large the area, the _____ the force, although this force will be exerted through a smaller distance.
larger
An object will float if its average density is ____ than the average density of the fluid it is submerged in.
less
Any object with a specific gravity ____ than or ___ to 1 will float in water.
less, equal
While flow rate is constant in a tube regardless of cross-sectional area, _________ of a fluid will increase with decreasing cross-sectional area.
linear speed
The flow rates may be the same at two different points, but the _____ can be different
linear speeds
Both ____ and ____ are fluids.
liquids, gases
cm^3 = ____
mL
All fluids and solids are characterized by the ratio of their ____ to volume. This is known as ____, a _____ quantity with no direction..
mass, density, scalar
Return flow to the heart is facilitated by ________________ of the skeletal muscles, which increases pressure in the limbs and pushes blood to the heart, and the expansion of the heart, which decreases pressure in the heart and pulls blood in.
mechanical squeezing
When water is placed in a container, a _______, or curved surface in which the liquid "crawls" up the side of the container a small amount, will form when the adhesive forces are greater than the cohesive forces.
meniscus
During inspiration, there is a ___________ pressure gradient that moves air into the lungs. During expiration, this gradient reverses.
negative
When air reaches the alveoli, it essentially has _________
no speed.
Pressure is the magnitude of the _____ force that is used
normal
Streamlines indicate _________ followed by tiny fluid elements as they move
pathways
If we express the object's specific gravity at a _____, this directly indicates the percent of the object's volume that is submerged
percentage
Fluids and solids can both exert forces ______ to their surface, although only solids can withstand ____(tangential) forces.
perpendicular, shear
When Po is equal to Patm, then Pg is equal to _____
pgz
Specialized measurement devices that can determine the speed of fluid flow by determining the difference between static and dynamic pressure of the fluid at given points along a tube
pilot tubes
The respiratory system is mediated by changes in ____ and follows the same resistance relationship as the circulatory system
pressure
A slight change in the radius of tube has a significant effect on the ________ ______, assuming a constant flow rate
pressure gradient
The nonconstant flow of the circulatory system can be measured as a _____
pulse
The density of a fluid is often compared to that of ___________ at 1 atm and 4 degrees celsius, a variable called _________.
pure water, specific gravity
Density is a _____ quantity
scalar
Pressure is a _____ quantity
scalar
An object will _____ if its average density is greater than that of the fluid
sink
Objects are are denser than the fluid, will _____.
sink
When the gravitational force is larger than the buoyant force, an object will _____
sink
Specific gravity can be used as a tool for determining if an object will _____ and ____ in water.
sink, float
Reynold's number depends on factors such as the ___, ___, and the __ roughness of any objects within the fluid.
size, shape, surface
The layer of fluid that is closest to a wall of a pipe in laminar flow will flow more ___ than the more interior layers
slowly
The combination of P+pgh gives us the ____ pressure, and is the same equation used for absolute pressure
static
Absolute pressure its the total pressure that is exerted on an object that is _______ in a ___.
submerged, fluid
_______ causes the liquid to form a thin but strong layer like a "skin" at the liquid's surface.
surface tension
The velocity vector of a fluid particle will always be _____ to the streamline at any point
tangential
Cohesion establishes ____ in the plane of the surface of the liquid toward the center; when there is an indentation on the surface, then the cohesion can lead to a net ____ force
tension, upward
Heart murmurs are heard because of ____ blood flow
turbulent
When the speed exceeds the critical speed, laminar flow become ____, generating eddies on the downstream side of the object
turbulent
______ flow is rough and disorderly. It causes the formation of ____, which are swirls of fluid of varying sizes occurring typically on the downstream side of an obstacle.
turbulent, eddies
When unequal pressures are exerted against objects, the forces acting on the object will add in ______, possibly resulting in acceleration.
vectors
Resistance of a fluid to flow
viscosity
n
viscosity
The critical speed depends on the physical properties of the fluid, such as its ___ and the _____ of the tube.
viscosity, diameter
Ideal fluids have no ____ and are described as ____.
viscosity, inviscid
Increased viscosity of a fluid increases its _________
viscous drag
Nonconservative force that is analogous to air resistance
viscous drag
Weight is the density times _____ and ______ due to gravity
volume, acceleration
Besides pressure, there is a loss of ____ from the circulation as a result of the differences between _____ and _____ pressures
volume, osmotic, hydrostatic
When an object is placed in a fluid, it will sink into the fluid only to the point at which the ______ of displaced fluid exerts a force that is equal to the ______ of the object.
volume, weight
Objects that are less dense than water will submerge enough of their volume to displace a volume of water equal to the object's _____.
weight