Midterm Review Flashcards
What is mass?
The amount of matter in an object
What is weight?
The attractive force of Earth’s gravity.
Gravitational force exerted on an object
What is velocity?
It’s a vector value.
Displacement or change in position.
It can be zero if return to starting point.
Velocity = displacement/time
What is speed?
It’s a scaler value.
Involves distance or total length of travel.
It’s always positive
What are scaler quanties?
Magnitude only
Additive
Examples are distance height weight and age
What are vector quantities?
Measure magnitude and direction
Can be additive
What is acceleration?
It’s a vector
Describes how velocity changes with time
It’s measured in m/s squared
How velocity (m/s) changes with each second
What is force?
It’s a push or pull
Newton’s second law
F=ma
Increased force equals increased acceleration
What is gravity?
The universal attraction between an object by a larger object.
G=9.8 m/s2
What is pressure?
Force per unit area.
P= force/area
- increases: either increase applied force or decrease area force is applied.
- decreases:Either decrease applied force or increase area force is applied
Example: popping a balloon with either your finger or a pin
**syringe: 1cm vs 2cm Doubling the diameter decreases pressure by factor of four
What is atmospheric pressure?
The weight of air above us. 5.79 quadrillion tons
-1 atmosphere = 760mmHg = 14psi
AKA: Barometric pressure
What is a barometer?
It measures atmospheric pressure.
What is a manometer.
An instrument for measuring the pressure acting on a column of fluid, especially one with the U-shaped tube of liquid in which a difference in the pressure acting in the two arms of the two causes the liquid to reach different heights in the 2 arms
What is an aneroid bellow gauge?
Do not require the presence of liquid.
Relies on the expansion or contraction of Bellows as the pressure changes.
What is a bourdon gauge?
Used with gas cylinders
Have a coiled tube coupled to a pointer.
Used to measure the pressure difference between the pressure exerted by the gas in a cylinder in the atmospheric pressure.
- effected by changes in atmospheric pressure
- total pressure = tank + atm
- The pressure inside an empty cylinder is equal to the atmospheric pressure
- In mountains there is less atmospheric pressure
What is work?
Work= force x displacement
- zero force equals zero work
- Zero displacement equals zero work
- Measured in joules
What is kinetic energy?
Energy in motion
The energy and mass has by virtue of being in motion
How does gas relate to work?
Gases that move equal work
- Breathing is work.
- The amount of work done by a gas is path dependent
- if there was no change in volume there was no work
- work = pressure x change in volume
What is energy?
The capacity to do work.
Measured in joules
What is a calorie?
The amount of energy to increase 1gm of water 1 degree C
What is potential energy?
Energy with is stored by virtue of its position
-airplane, battery, food
What is internal energy?
Source of kinetic energy plus potential energy of a system stored (molecular level)
-example: gas in a cylinder-moving molecules. Inside and compressed volume if released
What are thermodynamics?
The study of energy and how it’s interconverted
Temp A=B, B=C, A=C
What is the 1st Law of Thermodynamics?
Change in internal energy of a system is = to the sum of the heat process that cause energy to flow in and out of a system and work done.
energy can neither be created nor destroyed
What does endothermic mean?
Energy flows into system
What does exothermic mean?
Energy flows out of a system
What is the 2nd Law of Thermodynamics?
Heat flows from hot to cold when 2 bodies brought in thermal contact.
What is the 3rd Law of Thermodynamics?
Can’t lower a temp of an object to absolute zero.
What is heat vs temperature?
Heat is energy transferred as a result of different temps between objects. Temp is an arbitrary ranking of “hotness” or “coldness”
Example: heat house, use energy to increase temp.
What is specific heat?
The heat required to raise the temperature of 1gm of a substance by one degree C
- insulators: have a high specific heat
- conductors: have a low specific heat
What is heat capacity?
The ratio between the amount of heat added or removed from an object to change temp.
What is power?
The rate of doing work or the rate of energy expenditure
- measured in watts (watt = joules/second)
- P = F x V (average power = force involved and speed)
What causes a fluid to flow?
Gravity and pressure differences
What states of matter assume the shape of their contianer?
Liquids and gases
How do you determine an object’s density?
Mass divided by volume
What is specific gravity?
The relationship between an objects density and the density of water
What is Pascal’s Principle?
Confined fluids at at given pressure——> increase pressure——> applied change to every point in fluid
arterial line
What are hydrometers?
Uses to measure the density of a fluid.
Increased density = increased float level
What are hydrodynamics?
The study of fluids in motion
-2 useful properties are density and pressure
What is laminar flow?
- Smooth and orderly, unchanging pattern.
- Adjacent lawyers flow over.
- slow at edge, fast in the middle.
What is turbulent flow?
- not smooth
- continuously varying pattern of flow
- chaotic and changing
What is flow rate?
Volume passing a particular point /unit of time (L/min)
*smaller diameter: flow faster to keep same volume moving - flow faster via a smaller tube
What is Bernoulli’s Equation?
- As speed of a fluid goes up, pressure exerted by the fluid goes down.
- depends on speed and density of fluid.
**example: Venturi flowmeter. Used to measure fluid speed in pipes
V2>V1=P2
What is viscosity?
- A measure of a fluids resistance to flow
- increase viscosity = decrease flow
- decrease viscosity = increase flow
What is flow of liquid dependent on?
The pressure difference over the length of pipe
-to maintain flow, difference in pressure is proportional to pipe length, average speed of fluid, and inversely proportional to cross-sectional area
What is Poisueilles Equation?
- increase radius on the tube can increase flow
- short needle will increase flow
- increase IV height = increase pressure difference = increase flow
- increase viscosity will decrease flow
Flow rate=V/T
- flow is directly proportional to 4th power of radius
- double radius = increase flow 16x
- triple radius = increase flow 81x
- increase pressure differences = increased flow
- length of tube increased = decreased flow
- increase viscosity = decreased flow
- change of radius has most dramatic effect on flow
*for laminar flow only
What are some factors that cause flow to be turbulent?
- velocity increases
- tube wall rough
- kinks/bends >25 degrees
- flows through orifice
- density determines flow
*resistance to flow increases as flow becomes turbulent
What is Reynold’s Number?
- predicts turbulent flow
- 1500 - 2000 flow changes from laminar to turbulent
- directly proportional to velocity, density, and diameter
- inversely proportional to viscosity
Describe properties of gases
- have neither shape nor volume
- expands to fill space available
- no intermolecular forces between gas particles
What states of matter have the ability to flow?
Gases and liquids
What are intermolecular forces?
Determine how molecules interact with each other——> determined by chemical bonds and holds atoms into molecules
- determine microscopic properties
- all molecules, atoms, ions have inherent attraction as long as they don’t get too close
What is the electrostatic octet rule?
Every atoms tends to add/remove or share electors to end up with 8 valance electrons
Metals: release electrons easily: conductors/cations
Non-metals: attract anions
Solubility rule
*like dissolves like
Ex: Polar compounds dissolve more easily in other polar compounds
Ex: non-polar - oxygen poorly soluble in blood/water
-most organic compounds are hydrogen + carbon = hydrocarbons = non-polar
-a majority of organic compounds are not very soluble in water
What are polar compounds?
2 atoms of different electronegativity are bound together.
The bond is polar.
Water is polar
-polar molecules stick together and prevent non polar species from entering cell wall
What is surface tension?
- intermolecular forces
- in liquid state are attracted to neighbors by intermolecular forces
- H2O has a high surface tension = increase cohesion liquid - increase tendency of lungs to collapse in premature infants
What is LaPlace’s Law?
Explains why the surface tension on a blood vessel wall depends on the radius of the vessel
- wall tension is proportional to the radius of the vessel
- ex: if pressure same, larger vessel has greater wall tension than smaller
- aneurysms: spherical - changes Equation to R/2 so attempt to decrease wall tension
What is surfactant?
Surface acting agent reduces surface tension
-has polar (hydrophilic) and non-polar (hydrophobic) ends - attracts and pulls away
What is viscosity?
A measure of a fluids resistance to flow
-increase molecular forces
What is vapor pressure?
The pressure of a vapor in equilibrium with its liquid or solid state.
- increases with temperature increase: indications of liquid’s evaporation rate
- increased temp = increased vapor pressure of liquid with increase volatility = tendencies of liquid to evaporate
What is heat of vaporization?
The amount of energy to liberate 1 mole of liquid at its boiling point into a gas phase
What is boiling point?
Temperature at which vapor pressure is = ambient pressure
-depends on pressure. Increase ambient pressure = increase boiling point = pressure cooker
-bubbles deep in liquid = increase pressure secondary to increase temp
What is heat?
Increase kinetic energy, increase energy to overcome intermolecular forces.
Vaporization occurs as the molecules escape from liquid state into gas state
What is melting point?
Solid reversibly passes into liquid state. Opposite of freezing point.
-ionic bonds = strong = increase melting point—usually solid at room temperature
What is evaporation?
Has cooling effect.
-vaporization is endothermic (heat added) caused decrease temp - absorb heat from surrounding
What is condensation?
Releases energy
-heating effect—-> steam releases heat to convert back to liquids = steam burns - cooling of skin temp
