Physics Principles Flashcards
1
Q
Atom
A
Unit of Matter
Protons, neutrons, electrons
2
Q
Atomic Number
A
protons in nucleus of atom
3
Q
Atomic Mass
A
proteins, neurons in nucleus
4
Q
Isotope
A
Atom of element with unusual # of neutrons in nucleus
5
Q
Strong, Interatomic Bonds
A
- Covalent Bonds: atoms share outer shell of electrons
- Ionic Bonds: transfer of electron btw atoms
6
Q
Weak, Intermolecular Bonds
A
- Hydrogen bonds
- Van der Waals forces
–Dipole-dipole - btw polar substances
–London Dispersion forces - weakest, btw non polar substances
7
Q
Fluid
A
Substance that deforms continuously under application of a shear (ie tangential) stress
8
Q
Freezing Pt
A
Liquid –> solid
9
Q
Boiling Pt
A
Liquid –> gas
10
Q
Condensation Pt
A
Gas –> liquid
11
Q
Melting Pt
A
Solid –> liquid
12
Q
Latent Heat
A
Energy req’d to transform matter from one state to another
13
Q
Critical Temperature
A
–gases can be liquified by increasing pressure or by cooling
–Temp at which no amt of pressure will liquify gas
14
Q
Critical Pressure
A
Pressure above which liquid and gas cannot coexist at any temp
VP at critical temperature
15
Q
Critical Volume
A
Volume occupied by one mole of gas at critical temp, pressure
16
Q
Triple Point
A
T, P where all three states of substance coexist in thermodynamic equilibrium
17
Q
Critical Point
A
Liquid, vapor
Gas, vapor forms of substance coexist with same density and are indistinguishable
R of triple pt
18
Q
Newton’s First Law
A
Object remains at constant velocity unless acted on by an outside force
19
Q
Newton’s Second Law
A
Force = Mass x Acceleration
Force: SI unit = Newton (kg*m/s^2)
Used for von Frey filaments, other aesthesiometers
20
Q
von Frey Filaments
A
mechanical sensitivity test
thin plastic filaments applied to plantar surface of hind paw - filaments of different gauges/stiffness used to determine threshold that elects hind paw withdrawl
21
Q
Velocity
A
Rate of change of position
Magnitude + direction
Vector
22
Q
Acceleration
A
Rate of change of velocity
23
Q
Newton’s third law
A
For every action, there is an equal and opposite reaction
Forces must add up
24
Q
Weight
A
Measure of gravitational force exerted on mass
Weight = mass x acceleration DT gravity
Technically measured in Newton’s
25
M
26
Mass
Amt of matter an object contains
g
27
Energy
Capacity to Do Work
28
Work
Result of a force acting on an object in order to move said object
SI unit = joules (kg*m^2/s^2)
Work = force x distance (defibrillator)
Work = pressure x volume (PV loops)
29
Power
rate of doing work
SI unit = watt --> power expended when one Joule of work consumed in 1 second (J/s0
30
Efficiency
Efficiency = Energy output/energy input *100%
31
Pressure
Force per unit area
P=F/A
Pascal, Pa (N/m^2)
32
Newtonian Fluid
Viscosity unaffected by flow velocity, shear rate
33
Non Newtonian Fluid
Viscosity will change depending on shear rate
34
Viscosity
Fluid's resistance to flow
Results from frictional forces btw layers
Content of fluid affects viscosity as well eg polycythemia
Temp inversely related
35
Viscosity coefficient (eta)
Constant for Newtonian fluids
eta = shear stress, shear rate
36
Fahraeus-Lindqvist effect
Decrease in blood viscosity in very small vessels (10-200um) DT erythrocytes lining up in middle of vessel with plasma on periphery
37
LaPlace's law
Cylinder: T=PR
--vessels, conducting airways
Spherical Vessel: T=PR/2
--Alveoli, surfactant
Examples: RBB, LV hypertrophy, DCM
38
RBB and LaPlace's Law
RBB can prevent barotrauma as one source of compliance in the breathing system
39
LVH and LaPlace's Law
Persistent increase in LV overload (aortic stenosis) leads to increase LV pressure, so higher wall stress
Also applies to RVH
40
DCM and LaPlace's Law
LV radius increases, greater wall tension need to develop same LV pressure
41
Air Embolism and LaPlace's law
Pressure DT surface tension on meniscus which has smaller radius of curvature = higher than that acting on meniscus on other side of bubble
42
Laminar Flow
Parabolic Flow Pattern
Fastest at center, slowest at periphery
HP law
43
Turbulent Flow
Fluid flows unpredictably
Turbulence predicted by Reynold's #
**DENSITY**
>4000 flow turbulent, <2000 laminar, 2000-4000 = transitional with regions of both
44
Bernoulli Principle
Increase in flow velocity of ideal fluid accompanied by simultaneous reduction in pressure
pressure energy, kinetic energy, and potential energy equal on both sides
Increase in speed of fluid occurs simultaneously with reduction in static pressure or decrease in potential energy
45
Venturi Mask
Illustration of Bernoulli principle
Valve = high air flow oxygen entrainment valve
Uses injector - reduction of pressure DT high flow of oxygen, entrains air into O2 flow
46
Jet Entrainment
If hole in low pressure area (eg construction), fluid can be entrained from outside
47
Gas
Gaseous substance that normally in gaseous state at room temp, ATM pressure
47
Henry's Law
48
Vapor
gaseous substance normally liquid at room temp, ATM pressure
vapor formed via evaporation
49
Jet Entrainment
If hole in low pressure area (eg construction), fluid can be entrained from outside
49
Gas
Gaseous substance that normally in gaseous state at room temp, ATM pressure
49
Vapor
gaseous substance normally liquid at room temp, ATM pressure
vapor formed via evaporation
50
Henry's Law
Cx = k(h)*Px
Amt of gas dissolved in liquid directly proportional to pp of gas in equilibrium with liquid
51
Vapor
gaseous substance normally liquid at room temp, ATM pressure
vapor formed via evaporation
52
Coanda Effect
-Fluid will hug convex contour when flowing tangential to surface
-Effect = maldistribution of fluid flow
-Uneven distribution of flow in alveoli or myocardial infarction
53
Entrainment Ratio
DT both Bernoulli effect and jet entrainment
ER = entrained flow/driving flow
54
Three ways circle system cannot be arranged?
Unidirectional valves must go btw RB, P
FGF cannot enter btw exp valve, P
APL valve cannot be btw p, insp v
55
Adiabatic Compression or Expansion of Gases
Occurs without adding or removing energy from system
Why crack tanks before use
56
Jet Entrainment
If hole in low pressure area (eg construction), fluid can be entrained from outside
56
Gas
Gaseous substance that normally in gaseous state at room temp, ATM pressure
57
Fluid Logic and the Coanda Effect
Switching flow ventilator valve uses effect to advantage, supply oxyge/ventilation to patient but also allows expiratory venting without moving parts
58
Hygroscopic Material
attracts moisture from atmosphere
59
Thermometer: liquid in gas
uses liquid expansion with temp change
mercury thermometers
60
Bourdon Thermometer
Pressure change of gas
61
Thermistor
Uses T sensitivity resistor (semiconductor): as T falls, R increases
62
Thermocouple
Uses Seebeck effect, two different conductive materials
Seebeck effect: conductor generates voltage when exposed to T as a gradient
63
Infrared tympanic thermometers
thermopile to measure radiation emitted by eardrum
prone to false low readings
64
Wavelength
Distance btw identical points on consecutive waves
65
Amplitude
Distance btw origin and crest/trough
66
Frequency
of waves that pass point per unit time
67
Speed
wavelength x frequency
68
Isobestic point
Point at which two substances absorb certain wavelength of light to same extent
69
Simple Harmonic Motion
Motion repeats self, takes same time each cycle
Relationship btw mass, time vary in sinusoidal fashion
70
Harmonic Series
Occur when other frequencies which have frequencies that are exact multiples of the original are overloaded with initial (=fundamental) frequency
ex Fournier analysis
71
Fournier Analysis
Analysis, generation of various biological signals by breaking down any periodic waves into component sine, cosine waveforms
eg ABP, EEG, ECG
72
Doppler Effect
Frequency (and therefore pitch) of sound rises as it approaches observer and falls as it moves away
DT relationship of waves and observer, still occurs with no actual velocity change
US, laser
73
Piezo-Electric Effect
--Production of electrical current DT deformation of certain materials
74
Piezo-Electric Effect
--Production of electrical current DT deformation of certain materials
--Crystals frequently used for this purpose eg accelerometers, Doppler probes, US
--Electric current passing through crystals generates US waves, receiving crystals deformed by reflected sound waves --> produce electrical signal --> processed into image, sound
75
Ohm's law
V=IR
Voltage = Current * Resistance
Related to:
Change in pressure = Flow * Resistance
(vascular resistance)
76
Electrical Circuits
Resistors in series: Total = R1+R2+R3
Parallel: total = 1/R1+1/R2
Ex BV
77
Pseudocritical Temperature
Applies to a mixture of gases
temperature at which gas mixtures separate into their component parts
78
Critical Velocity
speed at which a falling object reaches when both gravity, air resistance are equalized on the object.
speed, direction at which the fluid can flow through a conduit without becoming turbulent.
79
Joules
Derived unit of SI energy
Conveys energy transferred to an object when 1 Newton force acts on object in direction of forces motion through a distance of 1m
