Physics MCAT section Flashcards
4 assumptions that underlie the ideal gas law and the equation? 1. volume of gas molecules is ________ 2. all collisions are perfectly _______ 3. there are no ________ interactions 4. the temperature is proportional to the _________ of the gas molecules
- volume of gas molecules is negligible 2. all collisions are perfectly elastic 3. there are no intermolecular interactions 4. the temperature is proportional to the average kinetic energy of the gas molecules PV= nRT
power equation
P = E/t E = energy t = time
Density equation
p = m/V m = mass V = volume
capacitance equation
C = Q/V Q = charge V = voltage
torque equation
T = rFsin0
electric field equation
E = F/q (charge)
momentum equation
p = mv
electric potential equation
V = U/q U= electric potential energy
what does arctan mean in trigonometry?
arctan value = opposite side/adjacent side
an object is dropped from the empire state building. what will happen to the acceleration of the object as it experiences air resistance during its downward fall?
its acceleration will decrease until the object starts moving with a constant speed. the force of air resistance will increase until its equal in magnitude/opposite direction to the weight of the object.
buffer equation
Ka = [conjugate base-][strong acid]/[weak acid]
pH =
-log [strong acid]
the bigger the Ka value,
the stronger the acid
the smaller the pKa value,
the stronger the acid
buffer equation?
pH = pKa + log [A-]/[HA}
weak or strong acid? HCl
strong
weak or strong acid? H2SO4
strong
weak or strong acid? HNO3
strong
weak or strong acid? acetic acid (CH3COOH)
weak
weak or strong acid? HF
weak
weak or strong acid? oxalic acid (COOH)2
weak
weak or strong base? sodium hydroxide (NaOH)
strong
weak or strong base? KOH
strong
weak or strong base? LiOH
strong
weak or strong base? NH4OH
weak
weak or strong base? NH3
weak
for a strong acid titrated with a strong base, what is the pH at equivalence point?
neutral - pH = 7
for a weak acid titrated with a strong base, what is the pH at equivalence point?
pH > 7
for a weak base titrated with a strong acid, what is the pH at equivalence point?
pH < 7
how many torr is equal to 1 atm?
760 torr
how many J is equal to 1 cal?
4.184 J
if heat flows out of the system, what sign does Q have? if heat flows into the system, what sign does Q have? if work is done on the system, what sign does W have? if work is done by the system, what sign does W have?
- -
how do you calculate K from celsius?
273.15 + celsius
0th law of thermodynamics?
if two systems are in thermal equilibrium with a third system, then all three systems are in thermal equilibrium
1st law of thermodynamics? 2nd law of thermodynamics? 3rd law of thermodynamics?
law of conservation of energy (U = Q - W) entropy will always increase for a spontaneous rxn entropy in a perfect crystal of any pure substance will always approach 0 as absolute temp approaches 0
newtons 1,2,3 laws?
1 - body at rest will remain at rest unless acted on by a force (motion in motion) 2. F = ma 3. Fab = -Fba
what is the density of water?
1000 kg/m^3 or 1 g/cm^3
what is specific gravity of a fluid?
- density compared to pure density of water SG = p/ 1 g/cm^3
pressure equation
P = F/A
conversion between torr, atm, and Pa?
1 atm = 760 torr (mmHG) = 1.013x10^5 Pa
what is absolute pressure? gauge pressure?
absolute - pressure in a fluid (P = P0 + pgz) P0 = atm at surface z = depth gauge pressure - difference between absolute and atmospheric (Pgauge = P - Patm)
what is pascals principle?
for a fluid that is incompressible - a change in pressure will transmit to every part of that fluid and the walls of the containing vessel
what is archimedes bouyancy principle?
Fbouy = p of fluid x g x V
will an object float or sink with a SG value less than or equal to 1? greater than 1?
less - float greater than 1 - sink
what is poeseuilles law? what ratio should you remember from this?
flow rate = (pi)r^4P / 8 (viscosity) L P = inverse of radius to power of 4
when talking about turbulent flow, what is eddies? critical speed? boundary layer?
eddies - swirls that form in fluid usually downstream of object critical speed - if flow exceeds this speed turbulent flow occurs boundary layer - the thin layer adjacent to the wall where laminar flow still occurs
for fluid in tube of diameter D, what is the equation for critical speed?
vc = NR (reynolds number)x viscosity/ (density x D) reynolds number depends on object
continuity equation
Q = v1A1 = v2A2 - indicates that fluid will travel faster in a narrower tube vs a wider tube -velocity and cross sectional area
bernoullis equation?
p1 + 1/2 pv^2 + pgh1 = P2 + 1/2pv^2 + pgh2 - explains pressure, height, velocity
venturi effect?
combination of bernoulli’s and continuity equation -describes relationship between cross-sectional area and pressure - smaller cross sectional area means higher dynamic pressure and lower absolute pressure
does venous or arterial circulation hold more blood?
venous, by 3 x
how to estimate logs? log (n x 10^m) log (920000000) ?
m + 0.n 8 + 0.92 = 8.92
0, 30, 45, 60, 90, 180 - for sin, cos?
sin - 0, 1/2, √2/2, √3/2, 1, 0 cos - 1, √3/2, √2/2, 1/2, 0, -1
accuracy (validity) ? precision ?
- ability of instrument to measure true value - ability of instrument to be consistent
case-control vs cohort vs cross- sectional studies?
case-control - look at outcomes, then assess risk factors cohort - look at risk factors, assess outcomes cross- sectional - different groups at one single point in time
bias vs confounding
bias - error in data collection phase (usually a result of inaccuracy) - BEFORE ANALYSIS confounding - error during analysis, incorrect relationship is characterized
internal vs external validity?
internal - ability to reproduce outcomes consistently from an experiment external - ability to reproduce research from experiment and apply it to a population
mean vs median vs mode
mean - the average mode - the number that repeats most often median - the number in the middle of data set
where is the tail of a positively skewed distribution? negatively skewed?
positively - tail is on the RIGHT negatively - tail is on the LEFT
when assessing outliers using interquartile ranges, when is a number considered an outlier?
when the number is more than 1.5 interquartile ranges (IQR = Q3 - Q1) below the first interquartile number or above the 3rd