Physics Denise PP Flashcards
The motion of atoms and molecules is described as
kinetic energy
The two types of internal energy that all matter possesses are ___ energy and ___ energy.
potential; kinetic
Potential energy is energy of _____
position
Kinetic energy is energy of _____
motion
The 3 states of matter are:
solid, liquid and gas
Solids have more (potential/kinetic) energy
potential
Solids maintain their shape through what type of attractive forces?
Van der Waals forces of attration
What type of energy will cause a solid to change shape?
kinetic energy (through heat)
T/F Liquids can be compressed
False
Gas molecules have more (potential/kinetic) energy?
kinetic
T/F When unconfined, gas will expand indefinitely.
True
Gases have (weak/strong) attractive forces
weak
T/F All matter is in constant motion
True
Liquids have more (potential/kinetic) energy
potential
The parts of a thermometer are:
reservoir and capillary tube
What is the first law of thermodynamics?
Energy can neither be created nor destroyed- it can be transformed
4 methods of heat transfer are:
conduction, convection, radiation, evaporation/condensation
How is heat transferred in conduction?
heat flows from the warm object to the cold object until it reaches equilibrium
How is heat transferred in convection?
through the mixing of fluid molecules at different temperatures via thermal currents
T/F Air is a good conductor of heat.
False
T/F Metals are good conductors of heat.
True
T/F Conduction and convection require direct contact between two substances.
True
Infant warmers use what method to transfer heat?
radiation
Increasing temperature weakens intermolecular forces through what mechanism of action?
by increasing molecular vibrations (kinetic energy)
What is melting point? (definition)
temperature at which solid becomes a liquid
What is latent heat of fusion? (definition)
the energy it takes to convert ice to water without changing the temperature of water (to go from melting point to water)
What is latent heat of vaporization? (definition)
the energy it takes to convert water to steam without increasing the temperature of steam (to go from boiling to steam)
The measure of an object’s ability to perform work is called _____
potential energy
T/F When an object cools, it gives up heat.
true
Does evaporation occur above or below boiling point?
below boiling point
Does vaporization occur above or below boiling point?
above
The boiling point of oxygen is (higher/lower) than room temperature
lower
In vaporization, liquid molecules have (higher/lower) energy levels?
higher
What is absolute humidity (definition)
the actual mass or content of water in a measured volume of air
What is relative humidity?
a ratio that compares the absolute humidity that is present to the gas’ capacity to hold water vapor
Variations in liquid pressure produce an upward supporting force called ____.
buoyancy
The temperature at which water vapor condenses back to its liquid form is called
dew point
What is the formula for measuring pressure?
Pressure = pounds / square inches
What is the formula for measuring liquid pressure?
Liquid pressure = height x density
What are the components of a mercury barometer?
scale (calibrated in centimeters and inches), evacuated glass tube, reservoir of mercury)
What are the components of an aneroid barometer?
evacuated metal container, fulcrum, scale
1 atm = ____ psi
14.7
760 mmHg = ____ cmH2O
1034
Attractive forces between like molecules is called _____
cohesion
Attractive forces between unlike molecules is called ______
adhesion
Force opposing fluid flow is called
viscosity
T/F Viscosity is directly proportional to the adhesive forces between molecules
False. Viscosity is directly proportional to COHESIVE force
The area of liquid gas interface is where you will find this force
surface tension
Tension on the wall of a sphere is the product of pressure times the radius of the chamber describes whose law?
LaPlace
What is the formula for LaPlace?
P= 4 ST/ r
Pascal’s principal means that a liquid container’s shape will not affect the pressure at the bottom. Pressure of a liquid is determined by what?
height times density
Capillary action is defined as ___
the upward movement of liquid into a narrow tube
Capillary action occurs as result of the combined actions of ______ forces and surface tension.
adhesive forces
Capillary action occurs as a result of the combined actions of adhesive forces and ____
surface tension
The pressure that evaporated water particles exert on the surrounding gas molecules is called
water vapor pressure
If the weight density of an object is less than 1 g/cm what will happen?
the object will displace a weight of water greater than its own weight and the upward buoyant force will overcome gravity (ie the object will float)
The formula for determining buoyancy is:
Buoyancy = density x volume
The buoyancy equation is used to measure what liquid property?
specific gravity
The ideal molar volume of any gas at STP is _____
22.4 Liters per mole
Gas pressure in a liquid is called
gas tension
What type of forces oppose fluid flow?
frictional forces
What is the equation for determining flow resistance?
Resistance = (P1-P2) /
flow
Resistance equals the pressure difference divided by the flow rate
The difference in velocity among concentric layers of flow is called ____
shear rate
T/F Surface pressure increases the pressure inside a liquid
true
If the radius of a drop of liquid increases, does the pressure within the fluid increase or decrease?
decrease
What is the clinical application for LaPlaces law which calculates the pressure inside a liquid bubble?
surfactant in alveoli creates liquid-gas interface. when radius of alveolus decreases, surface tension draws radius even smaller, increasing the pressure of gas inside the alveoli
Velocity is a measure of what?
speed (distance per time)
Flow is a measure of what?
volume per time
What causes liquid to flow opposite of gravity?
capillary action
Is heat required for evaporation?
YES! The energy for evaporation comes from either the water or the surrounding air
What is the Bernoulli principal?
fluid passing through a tube that meets a constriction experiences a significant pressure drop
Fluid that flows through a constriction increases its velocity- what happens to the lateral wall pressure?
it decreases
T/F A venturi tube widens just before its nozzle.
False- it widens AFTER the jet or nozzle
When the radius of the airway decreases by 1/2, the driving pressure (work of breathing) must increase by ____ to maintain the same flow rate
16 times
The inverse relationship between work of breathing and radius of the airway is shown by what law?
Pouiseuille
The density of oxygen is is ___ g/L
1.43
The density of nitrogen is ___ g/L
1.25
The formula for determining the density of a gas is?
molecular gram weight /
22.4 L (molar weight)
The higher the temperature, the (more/less) soluble a gas will be
less soluble– higher kinetic energy makes gas leave a solution, not go into it
What is the formula for Graham’s law?
1/square root of the gas’ gram molecular weight
What is the molecular weight of oxygen?
32 grams
What is the molecular weight of CO2?
44 grams
T/F Water vapor pressure is not affected by the percentages of other gases.
True. (It acts equally on all gases in a mixture)
Can pressure convert gas to a liquid?
Yes
In laminar flow, velocity is fastest where?
in the center of the stream
Do high flow rates increase or decrease resistance?
increase
Lateral wall pressure drops when a fluid passes through a constriction and velocity increases. What explains this?
Energy can’t be lost or gained- so when velocity increased, lateral pressure decreased – energy was transferred.
What are the two ways to increase entrainment of fluid?
increase jet diameter or increase the size of the entrainment port
How is humidity measured?
water vapor pressure ( a measure of pressure and temperature), absolute humidity (actual weight/volume of water) and relative humidity (percentage of absolute humidity/saturated capacity)
Describe relative humidity
how much water vapor a gas is holding compared to what it can hold (8 oz of water in a 16 oz cup can hold 50% more water)
Does absolute humidity change when the temperature changes?
No. Absolute humidity is fixed (it is absolute- get it?)
Does saturation capacity change when the temperature changes?
Yes- hot air holds more moisture than cold air
Does relative humidity change with temperature?
Yes
An increase in temperature will (increase/decrease) relative humidity?
Increase temperature decreases relative humidity
(4 oz water/6 oz container= 66% RH
4 oz water/8 oz container = 50% RH)
