Podcast
Questions and Answers
According to Newton's First Law, what will happen to an object at rest?
According to Newton's First Law, what will happen to an object at rest?
- It will oscillate between rest and motion.
- It will gradually slow down and come to a stop.
- It will spontaneously begin to move.
- It will remain at rest unless acted upon by a net external force. (correct)
Newton's Second Law of Motion describes force as being equal to mass times acceleration ($F=ma$). How does acceleration change if the mass of an object is doubled, but the force applied remains the same?
Newton's Second Law of Motion describes force as being equal to mass times acceleration ($F=ma$). How does acceleration change if the mass of an object is doubled, but the force applied remains the same?
- Acceleration quadruples.
- Acceleration doubles.
- Acceleration remains the same.
- Acceleration is reduced by half. (correct)
What is the key distinction between velocity and speed?
What is the key distinction between velocity and speed?
- Velocity includes direction, whereas speed does not. (correct)
- Speed measures instantaneous motion, and velocity measures average motion.
- Velocity is measured in m/s, while speed is measured in mph.
- Speed is a vector quantity, while velocity is a scalar quantity.
Considering vector addition, if a train is moving east at 30 mph and a person walks west on the train at 5 mph, what is the person's resultant velocity relative to the ground?
Considering vector addition, if a train is moving east at 30 mph and a person walks west on the train at 5 mph, what is the person's resultant velocity relative to the ground?
Which scenario best describes acceleration, according to its physics definition?
Which scenario best describes acceleration, according to its physics definition?
What is the relationship between force, area, and pressure?
What is the relationship between force, area, and pressure?
What does the SI unit of pressure, the pascal (Pa), represent?
What does the SI unit of pressure, the pascal (Pa), represent?
A pressure reading on a manometer is negative. What does this indicate about the measured system's pressure relative to atmospheric pressure?
A pressure reading on a manometer is negative. What does this indicate about the measured system's pressure relative to atmospheric pressure?
What is a key advantage of using automated oscillometry in noninvasive blood pressure (NIBP) measurement?
What is a key advantage of using automated oscillometry in noninvasive blood pressure (NIBP) measurement?
Which statement accurately describes a key property of fluids?
Which statement accurately describes a key property of fluids?
What is the relationship between viscosity and temperature when considering most liquids?
What is the relationship between viscosity and temperature when considering most liquids?
In hydrostatics, the pressure at a given depth in a fluid is independent of what factor?
In hydrostatics, the pressure at a given depth in a fluid is independent of what factor?
According to Pascal's Principle, what happens to the pressure in a confined liquid when an external pressure is applied?
According to Pascal's Principle, what happens to the pressure in a confined liquid when an external pressure is applied?
What is the fundamental principle behind buoyancy, as described by Archimedes' Principle?
What is the fundamental principle behind buoyancy, as described by Archimedes' Principle?
What happens to the fluid flow rate in a pipe if there are no leaks and the diameter of the pipe narrows?
What happens to the fluid flow rate in a pipe if there are no leaks and the diameter of the pipe narrows?
In a scenario where a fluid flows through a tube, how do the molecules at the center of the tube behave differently compared to those near the tube's walls, in laminar flow?
In a scenario where a fluid flows through a tube, how do the molecules at the center of the tube behave differently compared to those near the tube's walls, in laminar flow?
According to Poiseuille's Law, how is the flow rate of a fluid related to the radius of the tube it is flowing through?
According to Poiseuille's Law, how is the flow rate of a fluid related to the radius of the tube it is flowing through?
According to Poiseuille's Law, which of the following actions will cause the most dramatic increase in flow?
According to Poiseuille's Law, which of the following actions will cause the most dramatic increase in flow?
A Reynolds number above 2300 is indicative of what type of flow?
A Reynolds number above 2300 is indicative of what type of flow?
A venturi tube utilizes which principle to function?
A venturi tube utilizes which principle to function?
Increasing the pressure at the source of a fluid will affect what property?
Increasing the pressure at the source of a fluid will affect what property?
LaPlace's law explains the relationship between which properties of a fluid?
LaPlace's law explains the relationship between which properties of a fluid?
Surfactant is used for which purpose within the alveoli?
Surfactant is used for which purpose within the alveoli?
What are the two types of charge that exist?
What are the two types of charge that exist?
Which subatomic particle moves to exert electrical charge?
Which subatomic particle moves to exert electrical charge?
Which description about electrical conductors is correct?
Which description about electrical conductors is correct?
Which best describes the value calculated using Ohm's law?
Which best describes the value calculated using Ohm's law?
You halve the resistance of a circuit and triple the voltage of that circuit. According to Ohm's Law, how has the current changed?
You halve the resistance of a circuit and triple the voltage of that circuit. According to Ohm's Law, how has the current changed?
One of the equations for electrical power is: Power = Amps * Volts. Given this, what is the unit for electrical power?
One of the equations for electrical power is: Power = Amps * Volts. Given this, what is the unit for electrical power?
What term is given to a material's ability to impede electric flow?
What term is given to a material's ability to impede electric flow?
How does capacitance relate with positive and negative charges?
How does capacitance relate with positive and negative charges?
Within an isolated ungrounded circuit, what is the path by which electricity will flow?
Within an isolated ungrounded circuit, what is the path by which electricity will flow?
In the OR where ungrounded power systems are utilized, what does the line isolation monitor (LIM) measure?
In the OR where ungrounded power systems are utilized, what does the line isolation monitor (LIM) measure?
What is the greatest potential danger when combining electricity along with vulnerable patients?
What is the greatest potential danger when combining electricity along with vulnerable patients?
If a live wire comes into contact with a patient's skin in the operating room, the current should not flow through the patient because?
If a live wire comes into contact with a patient's skin in the operating room, the current should not flow through the patient because?
What combination of factors must be present to manifest a fire?
What combination of factors must be present to manifest a fire?
Which is the most common factor contributing to surgical fires?
Which is the most common factor contributing to surgical fires?
When using electrocautery, which is the more safe decision?
When using electrocautery, which is the more safe decision?
What is an appropriate course of action if you notice a surgical fire during a procedure? (Mnemonic: ERASE)
What is an appropriate course of action if you notice a surgical fire during a procedure? (Mnemonic: ERASE)
The use of lasers has many risks, one of them involves laser plume that may arise. What best describes this laser plume?
The use of lasers has many risks, one of them involves laser plume that may arise. What best describes this laser plume?
What should always occur before surgery due to known fire risk?
What should always occur before surgery due to known fire risk?
According to Newton's Third Law of Motion, if Object A exerts a force on Object B, what else must be true?
According to Newton's Third Law of Motion, if Object A exerts a force on Object B, what else must be true?
An airplane is flying at a constant altitude. Under what condition would the plane experience acceleration?
An airplane is flying at a constant altitude. Under what condition would the plane experience acceleration?
A rock is thrown upward. Neglecting air resistance, what force acts on the rock at the exact moment it reaches its highest point?
A rock is thrown upward. Neglecting air resistance, what force acts on the rock at the exact moment it reaches its highest point?
Which situation causes an increase in pressure on a specific area?
Which situation causes an increase in pressure on a specific area?
How does atmospheric pressure change as altitude increases, and what causes this change?
How does atmospheric pressure change as altitude increases, and what causes this change?
In a mercury barometer, what measurable quantity indicates atmospheric pressure?
In a mercury barometer, what measurable quantity indicates atmospheric pressure?
How does the density of the fluid affect the height of the column in a mercury barometer?
How does the density of the fluid affect the height of the column in a mercury barometer?
What is the significance of setting the 'zero' point on a pressure transducer?
What is the significance of setting the 'zero' point on a pressure transducer?
How does the viscosity of a fluid typically respond to an increase in temperature?
How does the viscosity of a fluid typically respond to an increase in temperature?
A fluid is at rest in a container. How does the pressure at a point in the fluid relate to the weight of the atmosphere and the depth of the point?
A fluid is at rest in a container. How does the pressure at a point in the fluid relate to the weight of the atmosphere and the depth of the point?
Why does the shape of a container not affect pressure at a given depth in a fluid?
Why does the shape of a container not affect pressure at a given depth in a fluid?
In a syringe filled with non-compressible fluid, how is the pressure affected when force is applied to the plunger?
In a syringe filled with non-compressible fluid, how is the pressure affected when force is applied to the plunger?
An object is submerged in a fluid. What happens when the buoyant force acting on the object is less than the object's weight?
An object is submerged in a fluid. What happens when the buoyant force acting on the object is less than the object's weight?
A hydrometer is placed in two fluids: Fluid A sinks lower than Fluid B. What does this indicate about the densities of the fluids?
A hydrometer is placed in two fluids: Fluid A sinks lower than Fluid B. What does this indicate about the densities of the fluids?
If a fluid is moving through a pipe and the pipe narrows, what happens to the speed of the fluid?
If a fluid is moving through a pipe and the pipe narrows, what happens to the speed of the fluid?
In laminar flow, what happens to the velocity of the fluid as you move from the walls of the tube toward the center?
In laminar flow, what happens to the velocity of the fluid as you move from the walls of the tube toward the center?
What effect will decreasing the length of tubing have on fluid flowing through it?
What effect will decreasing the length of tubing have on fluid flowing through it?
Compared to laminar flow, which of the following is a unique characteristic of turbulent flow?
Compared to laminar flow, which of the following is a unique characteristic of turbulent flow?
What does the Venturi effect describe about the relationship between fluid velocity and pressure in a constricted area?
What does the Venturi effect describe about the relationship between fluid velocity and pressure in a constricted area?
A doctor applies the principles of the Coanda effect when doing what?
A doctor applies the principles of the Coanda effect when doing what?
How are intermolecular forces related to surface tension?
How are intermolecular forces related to surface tension?
What is the effect of pulmonary surfactant on alveolar surface tension, and why is this important for lung function?
What is the effect of pulmonary surfactant on alveolar surface tension, and why is this important for lung function?
What happens to the pressures required to keep the alveoli open as the radius decreases, given that there is no surfactant?
What happens to the pressures required to keep the alveoli open as the radius decreases, given that there is no surfactant?
What best describes coulombs?
What best describes coulombs?
According to Coulomb's Law, how does the distance between two charged particles affect the force between them?
According to Coulomb's Law, how does the distance between two charged particles affect the force between them?
What is the relationship between electric field and electric potential energy?
What is the relationship between electric field and electric potential energy?
If an electrical wire is composed of atoms that easily release electrons, which best describes this wire?
If an electrical wire is composed of atoms that easily release electrons, which best describes this wire?
Per Ohm's Law, how are Voltage, Current, and Resistance related?
Per Ohm's Law, how are Voltage, Current, and Resistance related?
If a device has a high resistance and a fixed voltage, which is likely to describe this circuit?
If a device has a high resistance and a fixed voltage, which is likely to describe this circuit?
When current passes through a resistance, energy is dissipated. What form does this energy most commonly take?
When current passes through a resistance, energy is dissipated. What form does this energy most commonly take?
What best describes the function a transistor performs?
What best describes the function a transistor performs?
How can you determine electrical energy?
How can you determine electrical energy?
What is the difference between Direct Current and Alternating Current?
What is the difference between Direct Current and Alternating Current?
In circuits, what is the correct designation when resistors are oriented in parallel?
In circuits, what is the correct designation when resistors are oriented in parallel?
In ungrounded power systems in the operating room, what key advantage do they offer regarding electrical safety?
In ungrounded power systems in the operating room, what key advantage do they offer regarding electrical safety?
What electrical parameter does a Line Isolation Monitor (LIM) measure in an ungrounded power system?
What electrical parameter does a Line Isolation Monitor (LIM) measure in an ungrounded power system?
What best describes the most dangerous electrical hazard for a patient?
What best describes the most dangerous electrical hazard for a patient?
Why is it a safety best practice to utilize a three-pronged power cord?
Why is it a safety best practice to utilize a three-pronged power cord?
Which of the following best describes electrocautery?
Which of the following best describes electrocautery?
During which surgical procedure are fires most likely to occur?
During which surgical procedure are fires most likely to occur?
In the OR, what poses as the biggest fire hazard?
In the OR, what poses as the biggest fire hazard?
Why are fires a bigger risk with nitrous oxide?
Why are fires a bigger risk with nitrous oxide?
What is the BEST first step after visually identifying a surgical fire?
What is the BEST first step after visually identifying a surgical fire?
How does an increase in the intermolecular forces within a fluid generally affect its viscosity?
How does an increase in the intermolecular forces within a fluid generally affect its viscosity?
Consider a fluid moving through a pipe. What best describes the relationship between the pipe's diameter and the fluid speed, assuming a constant flow rate?
Consider a fluid moving through a pipe. What best describes the relationship between the pipe's diameter and the fluid speed, assuming a constant flow rate?
When comparing laminar and turbulent flow, which is more likely to cause greater pressure drop for the same flow rate?
When comparing laminar and turbulent flow, which is more likely to cause greater pressure drop for the same flow rate?
What is the purpose of using a Venturi mask?
What is the purpose of using a Venturi mask?
According to the principles behind the Coanda effect, how could you redirect a high-velocity stream of respiratory gasses without directly obstructing its path?
According to the principles behind the Coanda effect, how could you redirect a high-velocity stream of respiratory gasses without directly obstructing its path?
What characteristic of intermolecular forces is primarily responsible for the phenomenon of surface tension?
What characteristic of intermolecular forces is primarily responsible for the phenomenon of surface tension?
Per LaPlace's Law, how does alveolar radius affect the pressure required to keep the alveolus open, assuming surface tension remains constant?
Per LaPlace's Law, how does alveolar radius affect the pressure required to keep the alveolus open, assuming surface tension remains constant?
How does pulmonary surfactant change the relationship between alveolar size and pressure required to maintain alveolar stability?
How does pulmonary surfactant change the relationship between alveolar size and pressure required to maintain alveolar stability?
If you move two charged particles closer together in a vacuum, what happens to the force between them, based on Coulomb's Law?
If you move two charged particles closer together in a vacuum, what happens to the force between them, based on Coulomb's Law?
Which of the following describes the relationship between electric field and electric potential energy?
Which of the following describes the relationship between electric field and electric potential energy?
Why are metals typically better electrical conductors compared to nonmetals?
Why are metals typically better electrical conductors compared to nonmetals?
In an electrical circuit with constant resistance, how does increasing the voltage affect the current flow?
In an electrical circuit with constant resistance, how does increasing the voltage affect the current flow?
If all other factors are constant, how will a circuit with low resistance behave?
If all other factors are constant, how will a circuit with low resistance behave?
What is being amplified by a transistor?
What is being amplified by a transistor?
What key difference defines alternating current (AC) compared to direct current (DC)?
What key difference defines alternating current (AC) compared to direct current (DC)?
When multiple devices (resistors) are placed in a purely parallel circuit, how does that affect the current?
When multiple devices (resistors) are placed in a purely parallel circuit, how does that affect the current?
Why are ungrounded power systems utilized in the OR?
Why are ungrounded power systems utilized in the OR?
What parameter is measured by a Line Isolation Monitor (LIM) in an ungrounded power system?
What parameter is measured by a Line Isolation Monitor (LIM) in an ungrounded power system?
During surgery with electrocautery, what can be done to reduce likelihood of electrical injury?
During surgery with electrocautery, what can be done to reduce likelihood of electrical injury?
In the mnemonic 'ERASE' for surgical fires, what does 'E' stand for?
In the mnemonic 'ERASE' for surgical fires, what does 'E' stand for?
Flashcards
Newton's First Law
Newton's First Law
An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by a net external force.
Newton's Second Law
Newton's Second Law
Force equals mass times acceleration. (F=ma)
Newton's Third Law
Newton's Third Law
For every action, there is an equal and opposite reaction.
Mass
Mass
Signup and view all the flashcards
Average Velocity
Average Velocity
Signup and view all the flashcards
Scalar Quantities
Scalar Quantities
Signup and view all the flashcards
Vector Quantities
Vector Quantities
Signup and view all the flashcards
Resultant Vector
Resultant Vector
Signup and view all the flashcards
Acceleration
Acceleration
Signup and view all the flashcards
Force
Force
Signup and view all the flashcards
Gravity
Gravity
Signup and view all the flashcards
Weight
Weight
Signup and view all the flashcards
Mass (Units)
Mass (Units)
Signup and view all the flashcards
Weight (Units)
Weight (Units)
Signup and view all the flashcards
Pressure
Pressure
Signup and view all the flashcards
Pressure (Imperial Units)
Pressure (Imperial Units)
Signup and view all the flashcards
Pressure (SI Units)
Pressure (SI Units)
Signup and view all the flashcards
Pressure (Units)
Pressure (Units)
Signup and view all the flashcards
Pressure (Units)
Pressure (Units)
Signup and view all the flashcards
Air Pressure
Air Pressure
Signup and view all the flashcards
Mercury Barometer
Mercury Barometer
Signup and view all the flashcards
Manometer
Manometer
Signup and view all the flashcards
Aneroid Bellows Gauge
Aneroid Bellows Gauge
Signup and view all the flashcards
Bourdon Gauge
Bourdon Gauge
Signup and view all the flashcards
Gauge Pressure
Gauge Pressure
Signup and view all the flashcards
Oscillometry
Oscillometry
Signup and view all the flashcards
Fluid
Fluid
Signup and view all the flashcards
Friction (Fluid)
Friction (Fluid)
Signup and view all the flashcards
Viscosity
Viscosity
Signup and view all the flashcards
Hydrostatics
Hydrostatics
Signup and view all the flashcards
Hydrodynamics
Hydrodynamics
Signup and view all the flashcards
Pascal's Principle
Pascal's Principle
Signup and view all the flashcards
Hydrometer
Hydrometer
Signup and view all the flashcards
Flow rate
Flow rate
Signup and view all the flashcards
Laminar Flow
Laminar Flow
Signup and view all the flashcards
Transitional Flow
Transitional Flow
Signup and view all the flashcards
Turbulent Flow
Turbulent Flow
Signup and view all the flashcards
Poiseuille's Law
Poiseuille's Law
Signup and view all the flashcards
Reynold's Number
Reynold's Number
Signup and view all the flashcards
Bernoulli's Principle
Bernoulli's Principle
Signup and view all the flashcards
Venturi Effect
Venturi Effect
Signup and view all the flashcards
Coanda Effect
Coanda Effect
Signup and view all the flashcards
Surface Tension
Surface Tension
Signup and view all the flashcards
Surfactants
Surfactants
Signup and view all the flashcards
Laplace's Law
Laplace's Law
Signup and view all the flashcards
Electricity
Electricity
Signup and view all the flashcards
Electrical Charge
Electrical Charge
Signup and view all the flashcards
Coulomb's Law
Coulomb's Law
Signup and view all the flashcards
Electric Field
Electric Field
Signup and view all the flashcards
Volt
Volt
Signup and view all the flashcards
Electrical Current
Electrical Current
Signup and view all the flashcards
Conductor
Conductor
Signup and view all the flashcards
Insulators
Insulators
Signup and view all the flashcards
Ohm's Law
Ohm's Law
Signup and view all the flashcards
Study Notes
Newton's Laws of Motion
- Much of classical physics is based on Isaac Newton's three laws of motion.
- Newton's First Law (law of inertia) sates that an object at rest or moving at constant speed in a straight line will continue in that state until a net external force acts upon it.
- A body in motion tends to stay in motion unless acted upon by another force.
- Newton's Second Law (law of acceleration) specifies that Force is equal to mass times acceleration
F=ma. - Acceleration of a body is in the direction of and proportional to the force (F).
- Acceleration (a) is inversely proportional to the mass (m) of the body.
- Newton's Third Law (law of reciprocal action) sates that for every action, there is an equal and opposite reaction.
- Objects exert equal but opposite forces on one another.
Mass
- Mass is defined as the amount of matter in an object.
- All ordinary objects have mass.
- Electromagnetic radiation (such as visible light) does not have mass.
- Mass can be defined as the resistance of an object to acceleration.
- If an object needs to start moving, stop moving, or change direction, there needs to be a push.
Velocity
- Average velocity is formally defined as the displacement divided by the time it takes to make the trip.
- This is the average velocity over a finite time interval and does not account for how the velocity might have been changing over that time interval.
- Velocity differs from speed because speed is not a vector value, but a scalar value that does not specify a particular direction of motion.
- Speed involves distance, whereas velocity involves displacement.
- In a NASCAR race: High speeds equals zero velocity at finish.
Scalar vs. Vector
- Scalar quantities, such as distance, height, mass, and age, have magnitude only.
- Units typically need to be specified with scalar quantities.
- Speed is an example like the scalar quantity 5 mph.
- Vector quantities have magnitude and direction.
- The direction of the vector must be specified.
- Examples of vectors include velocity, weight, and the force applied to a syringe in order to inject a medication.
- Velocity is an example vector quantity of 5 mph east
- ECG is a vector diagram where axis deviation estimates the summation of forces that shift from normal electrical flow in the heart.
Vector Addition
- When adding vectors, consider both magnitude and direction.
- The sum of two or more vectors is called the resultant.
- Vector addition can be accomplished using the graphical or head-to-tail method.
Acceleration
- Acceleration is a vector describing how velocity changes with time.
- Average acceleration = Change velocity / Change time
- Velocity has units of m/s, and if m/s is divided by s, the result is m/s², the units for acceleration.
- Acceleration can involve changes in speed, direction, or both.
Force
- The physical world is dominated by four fundamental forces:
- Strong nuclear force (atoms)
- Electromagnetic force
- Weak nuclear force
- Gravitational force; this force pulls or accelerates all objects with a F = 9.81 m (or 32 feet)/sec per sec which affects daily living.
- A force is a push or a pull and is required to produce an acceleration.
Newton's F = ma Lawdescribes the relationship between force and mass.- For a given mass, a larger force can produce a greater acceleration.
Force / Gravity
- Gravity is the universal attraction between all objects with mass and is the weakest force.
- This equal attraction on objects is often hidden in everyday life because of the effect of air molecules interacting with falling objects.
Force / Weight
- At or near the Earth's surface, objects experience the attractive force of the Earth's gravitational field.
- Weight is simply the gravitational force exerted on an object by a much larger object like the Earth.
Force / Units of Mass and Weight
- Mass is the amount of matter contained in an object.
- Weight is the gravitational force exerted on an object by a much larger object.
- The SI unit of force is the newton (N).
- One newton of force results from accelerating a mass of 1 kg by 1 m/s².
- An object having a mass of 1 kg would have a weight of 9.8 N (gravity).
- A dyne is the force required to move 1 g of weight 1 cm/sec.
- Dynes are used in calculating systemic (SVR) and pulmonary vascular resistance (PVR).
- Key conversion factors:
- 1 lb. = 4.45 N
Pressure
- Pressure is the force per unit area /
pressure = force/area. - Pressure can be increased by:
- Increasing the applied force.
- Decreasing the area over which the force acts.
- Pressure can be decreased by:
- Decreasing the applied force.
- Increasing the area over which the force acts.
Units of Pressure
- In the British system, a common unit for pressure is pounds per square inch (psi).
- The SI unit of pressure is the pascal (the pressure exerted by the force of 1 newton over 1 square meter of area): Pa = N/m²
Units of Pressure / Other
- Torr (or millimeter of mercury, mmHg): the amount of pressure necessary to support a column of mercury 1 mm in height.
- Inches of mercury = 25.4 mmHg
- Atmosphere (atm): pressure necessary to support a column of mercury 760 mm in height.
- Bar: 1 bar = 100 kPa
- 1 mmHg = 1.36 cm H20
- 1 torr = 1 mmHg
Atmospheric Pressure
- Air pressure results from gravity pulling on the atmosphere resulting in a force that is spread over Earth's surface.
- If the air pressure is around 14.7 psi, estimate the total weight of the atmosphere with these conversions:
- 1 atm = 760 mmHg = 14.7 psi:
- 1 atm = 1 bar = 100 kPa = 1020 cm H2O
- 1 psi = 54 mmHg
- 1 torr = 1 mm Hg
- 1 kPa = 10.2 cm H2O = 7.5 mm Hg
Measuring Pressure / Barometer
- A simple mercury barometer consists of a tube closed at one end an open at the other.
- The tube is filled with mercury and inverted into a larger reservoir of mercury that is open to the atmosphere.
- This geometry results in a vacuum at the top of the glass tube as the mercury inside the tube runs downward, out of the tube, and into the reservoir of mercury.
- The pressure of the atmosphere pushes down on the surface of the mercury reservoir.
- There is essentially no pressure at the top of the inverted tube, and the pressure of the atmosphere will support a column of mercury to a height h.
- The height to which the column rises is dictated by this equation:
Patmosphere = pghwhere p is the density of the fluid, g is the acceleration due to gravity, and h is the height of the column in meters.- 1 atm of pressure supports a mercury column 760 mm tall.
Manometer
- A manometer is a U-shaped tube filled with a fluid of known density (such as mercury).
- Connect one end to the system whose pressure is being measured and leave the other end open to the atmosphere.
- The pressure of the system can be determined from: ΔΡ = Psystem – Patmosphere
- A positive ΔP means the system has a pressure higher than atmospheric pressure, and a negative ΔP means the system pressure is lower than atmospheric pressure.
Aneroid Bellows Gauge (Bourdon)
- Does not require the presence of a liquid to operate.
- It relies on the expansion or contraction of bellows as pressure changes.
- Gauges sealed regarding the atmosphere are used to measure changes in the absolute pressure.
- Gauges open to the atmosphere sample are used to measure gauge pressure.
Bourdon Gauge
- Bourdon Gauges are used on gas cylinders and are considered a type of aneroid gauge where is used for measurement of high pressures.
- It consists of a coiled tube, is to measure the pressure difference between the pressure exerted by the gas in a cylinder and the atm pressure.
- As gas at a pressure above atmospheric pressure enters the coiled tube, the tube coils, causing a connected pointer to ove across a scale.
Measuring (pressure) / Gauge Pressure and Total Pressure
- Specify what type of pressure is being utilized and how that pressure was determined.
- Barometers measure actual or absolute pressure.
- Manometers and Bourdon gauges measure gauge pressure (pressure of a system above or below atmospheric pressure) and are relative to atmospheric pressure, not absolute pressure.
- Zero results when the pressure in the cylinder is = to atmosphere.
Oscillometry
- Automated, noninvasive blood pressure (NIBP) measurement devices are the norm at many hospitals, clinics, and medical offices.
- Many of these devices are based on oscillometry where a method that relies on the measurement of blood pressure oscillations.
- One particularly effective technique is based on the piezoelectric transducer that gets distorted by pressure changes,.
- Electrical signal (a voltage) is directly proportional to the pressure change, and systolic/diastolic blood pressures are calculated by computerized algorithms based on the oscillatory pressure readings.
Fluids
- A fluid is any material that can flow with stress is the distribution of force per unit area.
- The stress, or force distribution, may be tangential (i.e., a shear stress) or it may be perpendicular (i.e., a normal force).
- Strain is the deformation caused by stress.
- Fluids continuously change shape (flow) when subjected to shear stress and respond in one of two ways to perpendicular forces:
- Resist compression (e.g., liquids)
- Become compressible and easily expandable (e.g., gases)
Fluids: A Definition
- Liquids and gases are considered fluids.
- Basic forces, such as those that result from gravity, friction, or pressure differences, cause fluids to flow (change shape).
- Friction is resistance to flow from surface interaction and is proportional to viscosity.
- Viscosity is the physical property of a fluid that relates shear stress to the rate of strain.
- Viscosity is the inherent property of a fluid that resists flow.
- Flow is the result of pressure forces in a fluid established by differences in pressure from one point to another, which creates a pressure gradient.
Viscosity (Temp?)
- Viscosity is proportional to friction.
- Viscosity increases with increasing intermolecular forces.
- Fluids with high viscosity, such as honey, do not flow readily.
- Fluids with low viscosity, such as water, flow more easily.
- The closer a fluid molecule is to a wall, the slower it moves:
- Adjacent regions of the fluid will have different speeds.
- The faster regions will flow past the slower ones.
- With an understanding of viscosity and flow, Poiseuille's law can be used to determine laminar flow (explained later).
Hydrostatics / Intro
- The study of fluids is divided into two major areas, hydrostatics and hydrodynamics.
- Hydrostatics is the study of fluids that are not moving, while Hydrodynamics is the study of moving fluids.
- Consider a beaker of water or the ocean: Only the weight of atmosphere is pushing down on the top surface of the water.
- Both the weight of the atmosphere and the weight of the water are pushing down on the bottom of the beaker, thus the force pushing down on the bottom of our beaker is larger than the force pushing down on the top of the water.
Hydrostatics / Pressure at Same Depth
- Assumes a point particle suspended in a fluid with density p:
- Since it is a point particle, it occupies no space or volume.
- No matter where it is placed in the fluid, the fluid will act the same, exerting the same pressure in all directions.
- Pressure remains independent of the container shape.
Hydrostatics / Pascal's Principle
- When an external pressure is applied to a confined liquid, it is transmitted unchanged to every point within the fluid.
- This principle can easily be understood by examining the pressure versus depth equation.
- if the pressure increases by 3 psi on the plunger of a syringe, the pressure will increase everywhere within the fluid by the same amount; if the fluid doesn't move or exit the syringe.
Hydrostatics / Buoyancy
- All fluids exert a buoyant force on objects immersed in them.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
