Physics and Math Flashcards
Scientific Method
- generate a testable question
- Gather data and resources
- Form hypothesis
- Collect new data (exp. or obs.)
- Analyze data
- Interpret data/existing hypothesis
- Publish (and peer review)
- Verify results
FINER method; whats it for?
for evaluating a research question to determine whether it will add to the body of scientific knowledge
- Feasible?
- Interesting?
- Novel?
- Ethical?
- Relevant?
positive vs. negative control in an experiment
positive ensures a change in dependent variable when expected, negative is to ensure no change in dependent variable when no change is expected
what is accuracy/validity? how does that compare to precision/reliability?
accuracy/validity is ability of an instrument to measure true value, precision/reliability is ability of instrument to read consistently
give example of binary/continuous/categorical variables
- binary - yes vs no; better vs. worse
- continuous - amount of weight lost; % cardiac improvement
- categorical variables - state of residence; socioeconomic status
cohort study
subjects are sorted into groups based on different risk factors (exposures), then assessed at various intervals to determine how many subjects in each group had a certain outcome
cross-sectional study
attempts to categorize patients into different groups at a single point in time
- ex. study to determine prevalence of lung cancer in smokers/nonsmokers at given point in time
case-control study
identifies number of subjects w/ or w/o a particular outcome, then looks backwards to assess how many subjects in each group had exposure to a particular risk factor
- ex. study where patients w/ and w/o lung cancer are assessed for smoking history
Hill’s criteria
- Temporality - exposure (I.V.) must occur before outcome (D.V.)
- Strength - as more variability in the outcome variable is explained by variability in study variable, relationship is more likely to be cause
- Dose-response relationship - as study or I.V. increases, there is proportional increase in response. More consistent relationship = more likely to be causal
- Consistency - relationship is found to be similar in multiple settings
- Plausibility - reasonable mechanism for I.V. to impact D.V. supported by existing literature
- Consideration of alternative explanations - if all other plausible explanations have been eliminated, remaining explanation is more likely
- Experiment - if an experiment can be performed, causal relationship can be determined conclusively
- Specificity - change in outcome variable is only produced by associated change in I.V.
- Coherence - new data and hypothesis are consistent w/ current state of scientific knowledge
bias vs. confounding
Bias is result of flaws in data collection phase of experimental/observational study, confounding is error during analysis
detection bias
when educated professionals use their knowledge in an inconsistent way
hawthorne effect (observational bias)
behavior of study participants is altered simply because they recognize that they are being studied
beneficence vs nonmaleficence
beneficence is the obligation to act in patient’s best interest, nonmaleficence is obligation to avoid treatments in which potential for harm outweighs potential for benefit
autonomy vs justice
autonomy is responsibility to respect patients’ decisions/choices about their own healthcare, justice is responsibility to treat similar patients w/ similar care and to distribute resources fairly
morally relevant differences
differences b/w individuals that are considered an appropriate reason to treat them differently
- ex. age (a transplant would be given to child vs old person)
equipoise
in a study comparing two treatments, you cannot approach research that one treatment is superior
internal vs external validity (generalizability)
internal related to how well a study is conducted (structure), external is how applicable the findings are to the real world
statistical vs clinical significance
statistical significance can be significant mathematically (like drop in BP by 1mmHg), but that would not be a notable change to a patient’s health
measures of central tendency
describe the middle of a sample
how to determine if outlier by IQR
- Q1=n/4, then average that&next highest
- Q3=3n/4, then average that and next highest
- IQR = Q3-Q1
- LF=Q1-1.5IQR and UF=Q3+1.5IQR
standard deviation formula
sqroot((x-u)^2/n-1)
independent vs dependent events
independent events have no effect on each other (e.g. rolling dice), dependent events affect each other (e.g. picking balls out of a hat)
Probability equation of 2 or more events occurring at the same time:
P(A and B) = P(A) + P(B)
Probability equation of at least one of two events occurring:
P(A U B) = P(A) + P(B) - P(A and B)
null hypothesis
always a hypothesis of equivalence
- says 2 populations are equal or that a single population can be described as equal to a given value
alternate hypothesis 2 options are?
can be directional (populations are not equal) or directional (mean of population A > mean of B)
decisions based on p-value
- p>a (0.05) - fail to reject null hyp. and not statistically significant
- p<a></a>
Type I error
likelihood we report a different b/w two populations when one doesn’t actually exist
Type II error; what is Beta
when we incorrectly fail to reject null hyp.
- Beta = props. of TypeII error
confidence vs. power (statistics)
power is prob. of correctly rejecting a false null hypothesis, 1-Beta
- confidence is prob. of correctly failing to reject a true null hypothesis
what are pie and circle charts for?
used to represent relative amount of entities and are especially popular in demographics
what are bar charts for?
used for categorical data, which sort data points based on predetermined categories
what are histograms for?
present numerical data rather than discrete categories
- useful for deterring mode of a data set b/c they’re used to display a distribution
what are box plots for?
used to show range, median, quartiles, and outlier for a set of data
vector calc.: dot product
used to find scalar quantity
(A)(B)cos0
vector calc.: cross product
used to find vector quantity
AxB = A(B)sin0
resultant vector right hand rule
- point thumb in direction of vector A
- extend fingers in direction of vector B
- your palm points in direction of vector C
circular motion centripetal force equation:
Fc = mv^2/r
what is the equation for torque?
what is the elastic PE equation?
r x F x sin0
r is length of lever arm, F is magnitude of force, theta is angle b/w lever arm and force
U = 1/2kx^2
4 physics equations names & their corresponding equations
- VAT - V = Vi + a(t)
- VAX - V^2 = Vi^2 + 2(a)x
- TAX - X = Vi(t) + 1/2a(t)^2
- XVT - X = Vavg(t)
what is the first law of thermodynamics?
energy always transferred, never created/destroyed
conservative vs nonconservative forces; examples?
- Conservative conserve ME & don’t dissipate energy, have PE associated w/ them (gravity, electrostatic forces)
- Nonconservative don’t conserve ME & dissipate energy (friction, air resistance, viscous drag)
what is the equation for work? power?
when is work pos. vs neg. ?
W = F(d) = change in KE = PdeltaV
P = W/t = deltaE/t
Work done BY a system is pos. and ON a system is neg.
explain work/pressure/volume for:
isochoric, isobaric, isothermal, adiabatic
- Isochoric - V is constant, P changes, W=0 (deltaU=Q)
- Isobaric - P is constant, V changes, W=PdeltaV
- Isothermal - constant temp. deltaU=0 (Q=W)
- adiabatic - no heat exchange Q=0, (deltaU=-W)
what is the work energy theorem?
net work done by forces acting on an object will result in equal change in object’s KE
Wnet = deltaK = Kf-Ki
what is mechanical advantage? equation?
What about efficiency
ratio of magnitudes of force exerted on an obj. by a simple machine (Fout) to the force actually applied on the simple machine (Fin)
MA = Fout/Fin
Efficiency = Wout/Win = (load)(load distance)/(effort)(effort distance)
how many degrees F are equal to one degree C?
1.8F = 1C F = 9/5C + 32
what is the thermal expansion equation? volumetric thermal expansion?
deltaL = a (L) deltaT deltaV = B (V) deltaT
differentiate b/w isolated vs closed vs open systems
- isolated - can’t exchange energy or matter
- closed - can exchange energy but not matter
- open - can exchange energy and matter
what are the only two process functions? which makes the rest of them ______ __________?
Work & heat; state functions
equation for change in internal energy
equation for heat gained/lost
equation for heat during phase change
deltaU = Q - W
q = m(c)deltaT
q = mL
what is the change in entropy equation and explain variables
deltaS = Qrev/T
Qrev is heat gained/lost(reversible); T is temp in K
what is the density equation? weight of a volume of a given substance? pressure equation?
p = mV Fg = pVg P = F/A
What is the hydrostatic pressure equation? gauge pressure?
P = Pi + pgz (z is depth) Pgauge = P - Patm
what is pascal’s principle equation?
what is the continuity equation?
P = F1/A1 = F2/A2 V = A1d1 = A2d2
Q = v1A1 = v2A2
what is archimedes’ principle and what does it deal with?
deals with buoyancy of objects when placed in a fluid
Fbuoy = pfluid(Vfluid displaced)g = pfluid(Vsubmerged)g
cohesion vs adhesion
COHESION is attractive force that molecules of liquid feels toward other molecules of same liquid, ADHESION is attractive force that molecules of liquid feel toward molecules of other substance
what is the equation for critical speed and define variables?
Vc = Nr(n)/pD
Nr is reynold’s number constant, n is viscosity, p is fluid density, D is tube diameter
what is bernoulli’s equation?
P1 + 1/2pv1^2 + pgh1 = P2 + 1/2pv2^2 + pgh2
what is eq. for electric field? electric potential energy? electric potential?
what are the 2 equations for magnetic field, define them too
how many gauss to 1 T?
E = kQ/r^2 U = kQq/r V = kQ/r
For wire: B = u0(I) / 2pi r
For loop: B = u0(I) / 2r
1T = 10,000 gauss
what is force on moving charge in magnetic field equation?
what is force on current-carrying wire equation?
relate electric potential and work and charge
F = qvBsin(theta)
F = ILBsin(theta)
V = W/q
what is the eq. for current? for resistance? how does temp. affect resistance?
what are eq. for power?
I = Q/delta(t) R = pL/A (p=resistivity; L = resistor length; A = cross sectional area) - higher temp. increases resistance
P = W/t = deltaE/t = IV = I^2R = V^2/R
what are the 2 eq. for capacitance? what about with capacitance and electric potential energy?
C = Q/V C = E0 (A/d) U = 1/2CV^2
differentiate b/w the 2 types of sinusoidal waves
what is angular frequency eq. and units
what is the speed of sound equation?
transverse is when oscillation is perpendicular to propagation, and longitudinal is when it is parallel
w = 2pi(f) = 2pi/T in RADIANS
v = sqrt (B/p)
T or F sound waves are transverse waves
what is doppler effect equation; describe it signs of numerator/denominator
FALSE they are longitudinal waves
f’ = f(v+/-vD)/(v-/+vS)
f’ is perceived freq., f is actual freq., vD is speed of detector, vS is speed of source
- TOP is TOWARD, bottom is away
what is intensity equation and units?
what is sound level equation and units?
what is beat frequency eq?
I = P/A W/m^2 B = 10log (I/Io) in dB
f beat = | f1 - f2 |
f1 and f2 are freq. close in pitch
what is eq. for length of a string for standing waves?
what is shortcut for harmonic and # antinodes of string attached at both ends? what about for open pipe?
what is eq. for closed pipe? (open one end closed the other)
- how do you count harmonics for closed pipe?
lambda = 2L/n L is string length, n is harmonic (fundamental freq. is n=1)
when string is attached at both ends, # antinodes = harmonic
- # nodes tells you which harmonic it is
lambda = 4L/n
- count how many quarter wavelengths there are!!!
(closed pipes are odd number harmonics!!!!!)
what is visible spectrum mnemonic for decreasing wavelength? what are the boundaries in nm?
what kind of images do plane mirrors create?
what is if i do i do equation? magnification equation?
ROY G. BV 400-700nm
plane mirrors -> virtual
1/f = 1/do + 1/di = 2/r m = -di/do = hi/ho
how to draw ray diagram for concave mirrors?
when is an object real for mirrors? lenses?
what kind of images are formed from convex mirrors?
which mirrors/lenses is F positive? negative?
CONCAVE: 1 ray leaving top of object goes straight to mirror then back through F, 1 ray from top of object goes through F to bottom of mirror then parallel back (image is where they insect)
REAL = same side for mirrors, opp. side for lenses
virtual, upright, smaller
F is positive for concave mirrors/convex lenses
F is negative for convex mirrors/concave lenses
what is mnemonic for single lens or mirror assuming do is + (object is in front of mirror)
what is index of refraction equation? snell’s law equation?
when does a light bend towards normal? away?
UV NO IR (Upright = Virtual, NO image if F away, Inverted = Real)
n = c/v n1sin(0)1 = n2sin(0)2
n2>n1 bends towards normal, n1>n2 away from normal
what is total internal reflection and when does it happen? equation for critical angle?
how do you draw ray diagram for lenses?
TIR is when all light reflected back into original material, when angle of incidence exceeds critical angle
Critical angle = sin^-1(n2/n1)
ray parallel to axis hits lens and through F, ray through F before lens refracts parallel to axis, ray to center of lens continues straight through
what is the power equation for a lens? units? variables?
hyperopia vs. myopia and the lenses they need
what is spherical aberration? chromatic aberration?
P = 1/f units=diopters P is power, f is focal length
hyperopia is farsightedness and needs converging lens, myopia is nearsightedness and needs diverging lens
blurring of periphery of an image as a result of parallel beams at edge of a lens
single slit and double slit equations? define variables
diff. b/w single and double slit (which has fringes)
asin0 = mLambda
- a=slit width, sin0 = angle light makes w/ axis, m is # of fringe
dsin0 = mLambda
- d=distance b/w slits, rest is the same
double slit has fringes, single doesn’t
positive image means image is _____ and negative image distance means image is ______
Real, virtual
energy of a photon equation? how does it pertain to Kmax and work function for a photon emitted?
what is mass defect? what is equation for binding energy using mass defect?
E = hf E = hf = Kmax + W (W = h(fT) )
diff in atomic mass as a result of binding energy in nucleus
E = mc^2
A & Z —-which is atomic number and which is atomic mass?
fusion vs. fission
Z is atomic number (# protons) and A is atomic mAss (# nucleons)
fusion is when small nuclei combine to form a larger nucleus, fission is when a larger nuclei breaks into smaller ones
explain alpha decay (and equation)
explain beta plus decay (and equation)
explain beta minus decay (and equation)
explain gamma decay (and equation)
explain electron capture (and equation)
alpha decay is when an alpha particle (4/2He) is emitted; Z decreases by 2, A decreases by 4
A/Z X –> A-4/Z-2 Y + 4/2alpha
beta + is when a proton is converted into neutron and a positron; A is unchanged and Z decreases by 1
A/Z X –> A/Z-1 Y + e+
beta - is when a neutron is converted into proton and e-; A unchanged and Z increases by 1
A/Z X –> A/Z+1 Y + e-
gamma decay is emission of gamma-rays (which have no charge), simply lowering E of parent nucleus; A and Z unchanged
A/Z X* –> A/Z X + gamma-ray
e- capture is when an unstable radionuclide captures an inner e- which combines w/ a proton to form a neutron; A unchanged, Z decreases by 1
A/Z X + e- –> A/Z-1 Y
what is half life equation?
what is lambda equal to?
N = (No)e^-lambda(t)
lambda = 0.693/T1/2
