MCAT- PHYSICS set1

Adiabatic

A process in which no heat exchange occurs (Q = 0)

Isobaric

A process in which pressure stays constant as volume changes.

If a tire is rolling along, what type of friction does it experience... how would it experience the other type?

it experiences static friction b/c the tire maintaines an instantaneous point of static contact with the road and, there fore experperiences static friction... will experience kinetic friction if it starts to SLIDE

What is work? (what is it NOT) what is another example kinda like work

it is NOT energy, but a measure of energy transfer also heat is a form of energy transfer

Isochoric.. aka?

A process in which volume stays constant as pressure changes (W = 0) aka: (isovolumetric)

Conductance units Conductivity units?

conductance = Siemens (S) Conductivity = Siemans/meter (S/m)

What are the 3 ways that heat can transfer?

conduction,convection, radiation

Specific heat. define and equation

definition: the amount of heat energy required to raise ONE gram of a substance by ONE degree Celcius (or kelvin) q = mcΔT

Conduction? good conductors vs bad?

direct transfer of E from molecule to molecule thru molecular collisions.. must be direct physical contact metals are good heat conductors (electron sea) Gases are poor heat conductors (so uch space between molecules)

What is Euler's number? ("e")

e = 2.718

What determines the absorption spectrum of a single atom?

he energy differences btwn grounds state e- and higher level e- orbits determine the frequencies of light a particular material absorbs (its absorption spectrum)

Helium should have a mass of 4.0319amu but it actually has a mass of 4.00260amu what is the mass defect and binding energy of this nucleus? constants: c² = 932 MeV/amu

mass defect = 4.03190 - 4.00260 = .02930amu This mass contributes to the binding energy of the nucleus so binding energy => E = mc² = 27.3 MeV (mega electron volts, I think)

What is mass? is it scalar or vector/

mass is a measure of a body's inertia (the amount of matter in the object)... it is scalar

What is an adiabatic process? What are the other 3 kinds of special thermodynamic processes

no heat exchange isothermal , adiabatic, isochoric/volumetric, isobaric

what does fusion mean? .. aka ?

phase change of solid to liquid aka fusion

spherical aberrations

sperical aberration is a blurring of the periphery of an image as a result of inadequate reflection of parallel beams at the edge of a lens. this creates an area of multiple images w/ very slightly different image distances at the edge of the image, which appears blurry

Interquartile range (4)

1) SORT Data in ascending order 2) get FIRST quartile (Q₁) by multiplying "n" by 1/4 a- if it is a whole number, the quartile is the mean of this position and the one higher b- if it is a decimal, round UP to the next whole number and take that as the quartile position 3) get the THIRD quartile (Q₃) by multiplying "n" by 3/4. Follow a and b rules to get the 3rd quartile 4) Calculate the interquartile range (IQR) with: IQR = Q₃ - Q₁ 5) USE IQR to find outliers. Outliers fall more than 1.5 IQRs below/above the 1st/3rd quartile range respectively

Electric field equation (2)

E = F/q = kQ/r² F/test charge OR k(source charge)/r²

Q98,1: Describe entropy on: 1) a macroscopic level 2) in statistical terms

Macroscopic: entropy can be thought of as the tendency toward disorder statistically: entropy is the measure of the spontaneous dispersal of energy at a specific temperature, increasing the number of available microstates for a given molecule

Bernoulli's equation Explain variables Explain components

P = Absolute pressure of the fluid ρ =density v = linear speed g = acceleration due to gravity h = height of the fluid above some datum 1/2ρv² = dynamic pressure = the pressure associated w/ the movment of a fluid (basically KE of fluid divided by volume) ρgh = looks like gravitational potential energy, basically the pressure associated w/ the cass of fluid sitting above some poisition P = "energy density (the ratio of energy per cubic meter). Systems at higher pressure have higher energy density P + ρgh = static pressure, basically like absolute pressure except here h = height above a datum while "z" was a depth below a certain point) Basically Bernoulli's equation is saying that the sum of static pressure and dynamic pressure will be constant w/in a closed container for an incompressible fluid not experiencing viscous drag

Capacitor potential energy

This equation tells you how much potential energy can be stored on a capacitor

Q52: An 80 Kg diver leaps from 10m cliff into the sea. Find the diver's PE at the top of the clif and when he's 2m under water.. use sea level as the datum

datum = zero otential energ position top of cliff = 7840J 2m under =-1568

Equation for heat during a phase change

during phase changes (ie ice -> water) there is no temperature change so q =mcΔT doesn't work. instead we use q = mL (mass x Heat of transformation or "latent heat")

how do you induce fission? What do nuclear power plants use

induce fission thru the absorption of a low energy neutron (only works in certain nuclei) of special interest are fission rxns that release more neutrons because these other neutrons will cause a chain rxn in which other nearby atoms can undergo fission <= this is what nuclear power plants use

insulator vs resistor

insulators = offer VERY high resistance resistors = offer resistance but less than insulators

Definition of a open vs closed pipe

open pipe = pipe that is open at BOTH ends (ie flute) Closed pipe = pipe that is closed at ONE end and open at the other

What type of biases are the following? 1) A physician may screen obese patients for hypertension and diabetes at a higher rate than healthy weight patients, inflating the true value of the secondary measurement. 2) Patients in the study for a given weight-loss drug and begin exercising more frequently to make healthier diet choices, thus artificially increasing the perceived effect of the drug. 3) Someone volunteering for a drug trial that requires clinical visits may be healthier or more likely to benefit from the study then someone who does not volunteer because they cannot make it to the hospital

1) Detection 2) observation/hawthorne effect 3) selection

Use the interquartile range to determine whether any data pt is an outlier: 22,22,22,24,23,25,36,20

1) SORT Data in ascending order 20,22,22,22,23,24,25,36 2) get FIRST quartile (Q₁) by multiplying "n" by 1/4 a- if it is a whole number, the quartile is the mean of this position and the one higher b- if it is a decimal, round UP to the next whole number and take that as the quartile position n = 8 (8 data pts) 1/4n = 2... so take the 2nd data pt and the one above it (22 and 22).... <- option a Q₁ = (22 +22) / 2 = 22 3) get the THIRD quartile (Q₃) by multiplying "n" by 3/4. Follow a and b rules to get the 3rd quartile n = 8.... 3/4(8) = 6...so take the 6th data pt and the one above it (24 and 25).... <- option a Q₃ = (24 + 25) / 2 = 24.5 4) Calculate the interquartile range (IQR) with: IQR = Q₃ - Q₁ IQR = 24.5 - 22 = 2.5 5) USE IQR to find outliers. Outliers fall more than 1.5 IQRs below/above the 1st/3rd quartile range respectively 1.5 (2.5) = 3.75.. SO any data pt that is ±3.75 from the lower/upper quartile is an outlier LOWER = 22 - 3.75 = 18.25 (no data pts below 18.25 so no lower outliers UPPER = 24.5 + 3.75 = 28.25, YES 36 is higher than 28.25 so there IS an outlier!!!!

Confidence interval

1) begin w/ a desired confidence level (95% is standard) and use a table to find its corresponding z- or t-score 2) multiply the z or t-score by the standard deviation 3) add or subratct this number from the mean (ie 5±1 is the confidence interval, 5 would be the mean, ±1 would be the z-score*standard deviation)

Q317: IF at time t=0 there is a 2mole sample of radioactive isotopes, how many nuclei remain after 45 minutes, assuming a decay constant of 2 hr⁻¹ you CAN use a calculator on this problem

22% of original sample remains = .44mole remain .44 * avogadros number = 2.64 e23 nuclei remain

Q66: A pulley system of 6 pulleys has an efficiency of 80%, A person is lifting 200kg w/ the pulley system A) The distance through which the effort must move to raise the load 4m B) the effort required to lift the load C) The work done by the person lifting the load through a height of 4m²

A) For the load to move thru 4m, all six of the supporting ropes must shorten 4m as well so you must pull thru 6 x 4 = 24m of rope B) Use efficiency to calculate effort required; Efficiency = load(load distance) / (effort)(effort distance) 0.8 =(200kg*9.8m/s²)(4m) / (EFFORT)(24m) effort = 408N C) Work done by person = 408N * 24m = 9800J

What are the 3 types of observational studies?

Cohort: subjects are sorted into 2 groups based on differences in risk factors (exposures) and then assessed at various intervals to dtermine how many subjects in each group had a certain outcome cross sectional: categorize patients into different groups ata single pt in time case-control: start by Identifying #subjects w/ or w/o a particular outcome, then look backwards to assess how many subjects in each group had exposure to a particular risk factor

How is a scalar calculated from the product of two vectors?

Dot product (A • B)

Define dynamic pressure vs static pressure

Dynamic pressure is the pressure associated with flow, and is represented by1/2pv^2. Static pressure is the pressure associated with position; static pressure is sacrificed for dynamic pressure during flow.

What is the equation for centripetal force? What is making the object want to LEAVE its circular path?

F,c, = mv²/r object wants to LEAVE b/c of inertia = the tendency to break out of its circular pathway and move in a linear direction along the tangent

What is the ratio of electrostatic force to gravitational force btwn an e- and a p+ note: proton mass = 1.67 e -27kg electron mass = 9.11 e-31kg e = 1.6 e-19 C k = 8.99 e9 N∙m²/C² G = 6.67 e-11 Nm²/C²

F,e, / F,g, = (kqq/r²) / (Gmm/r²) =kqq/Gmm = 2.27 e39 (NO UNITS

Total internal reflection

Light will be completely reflected if the angle of incidence is greater than the critical angle and light is traveling from a more dense medium to a less dense medium. basically all the light incident on a boundary is reflected back into the original material

T/F: when ther is only one path for the current to take, the current will be the same at every pt in the line... How will this help?

TRUE, it is the same at every pt in the line, including thru every resistor Once you know the current of the whole circuit, you can use V = IR to solve for the voltage drop across each resistor

Temperature vs heat

Temperature: proportional to the average kinetic energy of the particles that make up a substance Heat: the transfer of thermal energy from a hotter object w/ higher temperatures (energy) to a colder object w/ lower temperature(energy)

The binding energy per nucleon peaks at the element iron which implies that iron is ______

The binding energy per nucleon peaks at the element iron which implies that iron is the most stable atom

binding energy

This energy, called binding energy, allows the nucleons to bind together in the nucleus Given the strength of the strong nuclear force, the amount of mass that is transformed into the dissipated energy will be a measurable fraction of the initial total mass

Continuity equation

This is true b/c Q₁ = Q₂

Poiseuille's Law

Used to calculate the rate of LAMINAR flow through a pipe or confined space Q = πr⁴ΔP / 8ηL Q = flow rate (volume flowing per time) r = radius of tube P = pressure gradient η =viscosity of the fluid ("eta") L = length of pipe NOTE: relationship btwn radius and pressure gradient is inverse exponential to the fourth power. Even a very slight change in the radius of the tube has a significant effect on the pressure gradient, assuming a constant flow rate

What is the displacement of the earth per year?

ZERO, it is a circular path so by the end of the year it is back where it started (so it traveled a DISTANCE but had no displacement)

What is absolute pressure? what is it also called? What is the equation? What are the variables?

absolute pressure (aka hydrostatic pressure) = the total pressure that is exerted on an object that is submerged in a fluid fluids include both liquids and gases. Equation = P = P₀ + ρgz P = absolute pressure P₀ = incident or ambient pressure (the pressure at the surface, NOT necessarily 1atm, like in a pressure cooker, the pressure is higher) ρ = density of the fluid g = acceleration due to gravity z = depth of the object

Accuracy is also called what? Precision? which introduces bias?

accuracy is aka validity precision = reliability b/c bias is a SYSTEMATIC error in data, only an inaccurate tool will introduce bias

Shock waves

an obect that is producing sound while traveling at or aboe the speed of sound allows wave fronts to build upon one another at the front of the object. This creates a much larger amplitude at that pt. b/c amplitude of sound waves is related to degree of compression of the medium, this creates a large pressure differnetial or pressure gradient. This highly condensed wave front is called a shock wave, and it can cause physical disturbances as it passes through other objects. The passing of a shock wave creates very high pressure followed by very low pressure which is responsible for the phenomenon known as a sonic boom. Unlike depicitions in tv, a sonic boom can be heard at ANY time that an object traveling at or faster than the speed of sound passes a detector, not just at the pt that the speed of sound is exceeded (Mach 1) once an bject moves faster than the speed of sound, some of the effects of the shock wave are mitigated b/c all of the wave fronts will trail behind the object, destructively interfering w/ each other

When does turbulence arise? Is it all turbulent?

can arise when the speed of a fluid exceeds a certain critical speed which depends on the physical properties of the fluid (ie viscosity and the diabmeter of the tube. When the critical speed is exceeded, the fluid demonstrates complex flow patterns and laminar flow occurs only in the thin layer of fluid adjacent to the wall called the boundary later A significant amount of energy is dissipated from the system as a result of the increased frictional forces

3 causes of an outlier and 4 things you can do with one

causes: 1) true statistical anomaly (ie person over 7 ft tall) 2) measurement error (ie reading the cm side instead of inches) 3) distribution that is not approximated by the normal distribution (ie skewed distribution w/ a long tail If measurement error = exclude from analysis If 1 or 3 = weight to reflect its rarity, include it like you normally would, exclude it from analysis <- decide on one of these BEFORE the experiment begins, not when one is found

Capacitors (esp parallel plate) how are they set up? what do they create?

ciruit elements that can hold charge at a particular voltage. When 2 electrically neutral metal plates are connected to a voltage source, positive charge builds up on the plate connected to the positive (higher potential) teminal, and negative charge builds up on the plate connected to the negative (lower potential) terminal the separation of charges sets up an electric field btwn the plates. The electric field btwn the plates of a parallel plate capacitor is a uniform electric field w/ parallel field vectors

Q170: Suppose a wire of length 2.0m is conducting a current of 5A toward the top of the page and through a 30 gauss uniform magnetic field directed into the page. What is the magnitude and direction of the magnetic force on the wire

convert gauss -> Telsa theta =90 F,B, = ILBsinθ 3 e-2 N use RHR for direction = F,B, = to the left

What are the 2 current patterns? Which is tested on the MCATs? Electrons flow from points of ___ electrical potential to points of ___ electrical potential. What about current?

current patterns = Alternating or direct MCAT tests direct currents Electrons flow from points of LOW electrical potential to points of HIGH electrical potential. Current goes the opposite direction

3 types of materials (in terms of magnetism) and definition

diamagnetic: atoms w/ NO unpaired e- and have no net magnetic field... These materials are slightly repelled by a magnet and thus are "weakly antimagnetic" paramagnetic: have UNPAIRED electrons so have a net magnetic dipole HOWEVER the atoms in these elements are usually randomly oriented so that the material itself creates no net magnetic field. If they are in the presneces of an external magnetic field, they will align their magetic dipoles and become weakly magnetized. If the external magnetic field is removed however, the thermal energy of the individual atoms will cause the individual magnetic dipoles to reorient randomly (ex: aluminum, copper, gold ferromagnetic materials; have unpaired electrons and permanent atomic magnetic dipoles are normally oriented randomly so that the material has no net magnetic dipole. However, UNLIKE paramagnetic materials, ferromagnetic materials WILL become strongly magnetized when exposed to a magnetic field or under certain temperatures. Ex = iron, nickel cobalt

Diffraction gratings thin films exampls of both?

diffraction gratings = consist of multiple slits arranged in patterns (ie CD) thin films = can also cause interference patterns bc light waves reflecting off the external surface of he film interfere w/ light waves reflecting off the internal surface of the film (ie soap bubbles or oil puddles) note, interference here is not btwn diffracted rays, but btwn reflected rays

What is dot product vs cross product and which uses the right hand rule/the circle i,j,k thing.... also, how does the ijk thing work?

dot product = a∙b = |a||b|cos(x) cross product = a x b = |a||b|sin(x) = use right hand rule or ijk circle thing.. rhr = palm in direction of A, fingers wrap towards B, thumb points towards answer circle thing = write ijk in a clockwise circle.... 1) the answer is going to be the letter NOT being multiplied (ie if it is i x j, the answer is k!!!!) 2) if you go clockwise around the circle (i.e. i x j) the answer is positive.... if you go counter clockwise around the circle (ie. j x i) the answer is negative

What do the electrons from the photoelectric effect do?

electrons liberated from the metal by the photoelectric effectwill produce a net charge flow per unit time, or current provided that the light beam's frequency is above the threshold frequency of the metal, light beams of greater intesnity produce larger current in this way. the higher the intensity of the light beam, the greater the #photons per unit time that fall on an electrode, producing a greater number of electrons per unit time liberated from the metal When the light's frequency is above the threshold frequency, the magnitude of the resulting current is directly proportional to the intensity and amplitude of the light beam

Work-energy theorem₂₁

expression of the relationship btwn work and energy. In its mechanical applications, it offers a direct relationship btwn the work done by all the forces acting on an object and the change in kinetic energy of that object the net work done by forces acting on an object will result in an equal change in the object's kinetic energy. In other words: See picutre W,net, = ΔK = K₂ - K₁

Draw ray diagram(s) for convex mirrors

forms only a VIRTUAL UPRIGHT and REDUCED image, regardless of the position of the object

When can you assume conservation of energy?

in low viscosity fluids with laminar flow

independence and dependence in probability

independence = events have no effect on each other (ie flipping a coin dependence = events do effect each other, (ie the order changes the probability).. ie picking cards from a deck and NOT putting them back

difference btwn insulators and conductors

insulators usually hold their electrons close to their nuclei. don't easily distribute charge over the surface conductors have sea of free electrons which allows the charge to be distrubuted approximately evenly upon the surface of the conductor (metals/electrolytic solutions

Intensity definition equation variables units what is it proportional to?

intensity is the average rate of energy transfer per area across a surface that is perpendicular to the wave. In other words, intesnity is the power (P) transported per unit area (A) I = P/A I = W/m² (watts per square meter PROPORTIONAL to 1/r^2 (distance) and Amplitude^2 So doubling the amplitude produces a sound wave w/ 4x the intensity

beneficence

it must be our intent to cause a net positive change for both the study population AND the general population (and do our best to minimize harm) should also be least invasive, painful and traumatic way possible equipoise: in studies comparing 2 potential treatments, one cannot approach the research w/ the knowledge that one treatment is superior to he other AND if it becomes evident that one treatment option is clearly superior, the trial must be stoped early bc providing inferior treatment is net harm

Q313: suppose a parent nucleus X alpha decays as follows: ²³⁸₉₂X → ??Y + α What is the mass number and atomic number of Y?

mass number = 234 atomic number = 90

1st law of thermodynaics states?

mechanical energy is conserved: energy is never created or destroyed, just transferred from one form to another... this does NOT mean that total mechanical energy will necessarily remain constant. mechanical energy =accounts for potential and KE but not for other forms like thermal energy (can be transferred as a result of friction)... this energy will be "lost" but really just dissipated from the system and not accounted for by the equation so is NOT a violation of the 1st law of thermodynamics t

If a graph is "negatively skewed" will the mean be higher or lower than the median?

negatively skewed = has its tail on the LEFT and the mean is lower than the median (b/c the mean is more susceptible to outliers than the median) the direction of the skew is determined by its TAIL, not the bulk of the distribution. ie the OUTLIERS are negatively skewed (so the tail trails to the left/negative side

What are the requirements to have a nonzero electric field? A nonzero magnetic field? A nonzero magnetic force

nonzero electric field = have a charged particle non zero magnetic field = MOVING charged particle nonzero magnetic force = external electric field acting on a charge moving in any direction except parallel or antiparallel to the external field

Calculating independent vs dependent probabilities

probability of A AND B happening = (Probability of A x probability of B x etc) P(A∪B) = P(A) x P(B) Probability of A OR B happening = (Probability of A + Probability of B + etc) - probability of A and B and etc P(A∩B) = P(A) + P(B) - P(A and B)

3 types of biases

selection bias is when subjects used for the study not representative of the target population. Detection bias results from educated professionals using their knowledge in an inconsistent way. Observation bias (a.k.a. the Hawthorne effect) posits that the behavior of study participants is altered simply because they recognize that they are being studied.

Q276: An object is 15cm to the left of a thin diverging lens w/ a 45cm focal length. Find: where the image is formed upright/inverted real/virtual what is the radius of curvature? assume the lens is symmetrical and made of glass w/ a non-negligible thickness and an index of refraction of 1.50

solution: image distance if found using 1/f = 1/o + 1/i bc lens is diverging, the focal length has a negative sign (f = -45cm). The object has a + sign so now we can solve for i =? i = -11.25cm - means that it is virtual and upright (on the same side as the light source) use lens maker equation to figure out radius of curvature b/c lens is symmetrical, the radii are equal but opposite in sign: as the light progresses from left to right, the first surface of the lens is concave (r,1, < 0 ) and the second surface is convex (r₂ > 0) so: r = -2f(n-1) = 45cm

First Law of Thermodynamics equation and sign conventions

ΔU = Q - W Basically: Change in total internal energy of a system = amount of energy transferred TO the system in the form of heat - amount of energy transferred FROM the system in the form of work IF ΔU = positive then temperature is INCREASING IF Q (heat) = positive then heat is going INTO the system IF W = positive then work is being done BY the system

Alpha decay/alpha particle

alpha decay is the emission of an alpha particle alpha particle = ⁴₂He nucleus (has 2 protons, 2 neutrons and zero electrons) it is massive comapred to beta particle and carries double the charge (He⁺²) they interact w/ matter very easily and do not penetrate shielding (such as lead sheets) very extensively

what types of atoms would you expect to release the most energy?

b/c the binding energy per nucleon is greatest for intermediate sized atoms (that is, intermediate sized atoms are most stable), when SMALL ATOMS COMBINE or LARGE ATOMS SPLIT, a great amount of energy is released

Bar charts and histogram

bar chart = uses categories (ie dog breeds) histogram =present numerical data rather than discrete categories

Mass defect, why does it happen?

basically some of the matter is converted to energy when the protons and neutrons (nucleons) come together to form the nucleus, they are attracted to each other by the strong nuclear force (strong enough to more than compensate for the repulsive electromagnetic force btwn protons) but it only works over small distances the bound system is at a lower energy level than the unbound constituents and this difference in energy must be radiated away as heat/light/other electromagnetic radiation before the mass defect becomes apparent (this is called binding energy)

In a single slit experiment, as the slit becomes narrower, the central maximum becomes _____

becomes wider

Beta decay and β particles

beta decay = emission of a beta particle beta particle = an electron OR a postiron NEGATIVE Beta decay = emission of a negative beta particle (ie an electron, signified by e⁻ or β⁻) -they are emitted by the nucleus when a neutron the neutron decays into: a proton, a β-particle, and an antineutrino (denoted as a "v" with a bar on top) -ATOMIC number (Z) = increases by 1 (b/c a proton is formed) -MASS number does not change POSITIVE beta decay = emission of a positive beta particle (ie a positron = same mass as electron but + charge, signified by e⁺ or β⁺) -emitted when proton is converted to a neutron (neutrino is also released) -ATOMIC number (Z) = decreases by 1 (b/c a proton turns into a neutron) -MASS number does not change

Bias vs confounding? what are the 3 types of bias?

bias = result of flaws in the data collection phase of an experimental or observational study -selection, detection, observation confounding = error during analysis

What are 3 ways we can group variables? What do we do once we've accounted for them?

binary (yes/no... better/worse) continuous (amount of weight lost, percent improvement) categorical (state of residence, socioeconomic status) use these variables to create a regression model Regression analysis will demonstrate a relationship (ie linear, parabolic, etc)

How do you calculate buoyancy?

bouyancy = the weight of gravity and the weight of gravity = Fg = ρvg

How does an electron go from a low energy state to a high one/ what is this called? What is the opposite

by absorbing a photon of light of precisely the right frequency to match the energy difference btwn orbitals (absorption opposite = emission = letting out a photon of light w/ energy equal to the difference btwn the 2 orbits

Law of index of refraction equation

c = speed of light in vacuum v= speed of light in the medium n will always be GREATER than one (it is one when light is in a vacuum)

Electron capture?

certain unstable radionuclides are capable of capturing an inner e- that combines w/ a proton to form a neutron (neutrino is released). The atomic number is now one less than the original but the mass number remains the same e- capture is a rare process that is perhaps best thought of as the reverse of β⁻ decay (.A.,Z,)X + e- → (.A.,Z-1,)Y

What does it indicate if median and mean are far from each other

could indicate that theire is an outlier or skewed distribution

Double slit equation: what does it tell us, what is it? variables?

d sinθ = (n + 1/2)*λ d = distance btwn the slits

Standing wave's frequency (string/open pipe)

f = nv/2L

Doppler effect equation equation variables sign convention

f' = preceived frequency f = actual emitted frequency v = speed of sound in the medium v,D, = speed of the detector v,s, = speed of source Use the UPPER sign if thedetector/source are moving TOWARD each other Use the LOWER sign if the detector/source is moving AWAY from each other SO: imagine you are driving down the street and you hear an ambulance approaching from behind. (detector = you, source = ambulance) so by YOUR standard, you are driving AWAY from the ambulance so the BOTTOM sign should be used (in this case its negative) in the numerator (v,D, =detector BUT, the ambulance driver is driving TOWARDS you so the TOP sign should be used in the denominator (in this case its also negative) so it is: f' = f [ (v-v,d,) / (v - v,s,)]

When will sound travel the fastest? the slowest? What is the speed of sound in air at 20°C

fastest = solid w/ low density slowest = very dense gas speed of sound =343m/s

What are fluids? What are solids?

fluids = characterized by their ability to flow and conform to the shapes of their containers solids = do not flow and are rigid enough to retain a shape independent of their container

What about when lenses are NOT in contact with each other? what is the magnification?

for lenses not in contact the image of one lens becomes the object of another m,equ, = m₁ x m₂ x m₃ ...etc

Null hypothesis

hypothesis of equivalence. says that 2 populations are equal or that the 1 population can be described by a parameter equal to a given value

Q267: An object is placed 7cm in front of a concave mirrror w/ radius of curvature = 10cm. Determine: image distance magnification real/virtual inverted/upright

i = +17.5cm +i = image is infront of mirro and thus real since o > 0 and its real image means the image is inverted m = -2.5 (so inverted image and enlarged)

What is the ideal pulley? If you had the ideal pulley, what could we say about work/

ideal pulley = massless and frictionless if this was the case we could say hat the work going INTO the system (ie exerting some force, F, through a distance of rope, d) is EQUAL to the work that comes out of he system (lifting some mass to a certain height)

forced oscillation how can it be made bigger?

if a periodically varying force is applied to a system, the system will be driven ata frequency equal to the frequency of the force = forced oscillation if the frequecy of the applied force is close to that of the natural frequecny the amplification becomes much bigger (called "resonating") ie parent PUSHING their child on a swing (parent is the force pushing at the frequency of the swing's natural frequency

The center of mass is the geometric center if and ONLY if ____

if and only if it is a uniform object (ie the mass is distributed evenly throughout the entire mass). so this does not hold true for the human body or anything.... our center of gravity is not necessarily our geometric center

center of curvature is ?

is a point on the optical axis located at a distance equal to the radius of curvature from the vertex of the mirror; in other words ,teh ceter of curvaturewould be the center of the spherically-shaped mirror if it were a complete sphere

How does the eye work?

it uses real lenses. the cornea acts as the primary source of refractive power b/c the change in refractive index from the air is so significant. Then light is passed thru an adaptive lens that can change its focal length before reaching the vitreous humor. It is further diffused thru layers of retinal tissue to reach the rods and cones. At this pt, the image has been focused and minimized significantly, but is still relatively blurry. Our nervous system processes the remaining errors to provide a crisp view of the world

magnification equation

m = -i/o negative magnification means INVERTED image positive magnification means UPRIGHT imiage if |m| < 1 (ie a fraction) then the image is reduced (smaller than the object) If |m| > 1 then the image is enlarged

What is isotopic notation why is it important?

mass number (A) = #protons plus neutrons atomic number (Z) = number of protoons in the nucleus When balancing nuclear equations, it is important to balance the number of nucleons on both sides by balancing BOTH the atomic numbers and the mass numbers

alternative hypothesis

may be nondirectional (that populations are not equal) or directional (ie the mean of population A is greater than the population B)

What are 3 measures of central tendency (and what are measures of central tendency in general?

measures of central tendency = measures that describe the middle of the sample mean, median, mode mode = the number that appears the most often in a set of data (may be multiple modes in a data set or even no mode)

Box plot

middle line = mean ends of the boxes = 1st and 3rd quartile ends of whiskers = max and min dots = outliers

Respect for Persons includes? and 2 other things that fall under this category?

need for honesty btwn subject and researcher and ideally no deception. also informed consent (telling them the risks, benefits, procedures, goals). also no coercive influence over subjects (ie teacher/student coercion or extreme financial incentive). subject can cease participation Vulnerable persons = children, pregnant women, prisoners

Q205: The voltage across the terminals of an isolated 3μF capacitor is 4V. If a piece of ceramic having dielectric constant κ = 2 is placed between the plates, find the new charge, capacitance, and voltage of the capacitor

new charge = 12µC Capacitance = 6µF New voltage = 2V

What are the 4(ish) types of distribution?

normal/standard = bell curve skewed = contains a tail on one side of the data set. bimodal = have 2 peaks w/ a valley in between

Second law of thermo dynamics in terms of the "thermo" part of thermodynamics

objects in thermal contact and not in thermal equilibrium will exchange heat energy such that the object w/ higher temp will give off heat energy to the object w/ lower temp until both have the same temp at thermal equilibrium

Open pipe has ___ at one end and ___ at the other CLosed?

open pipe has antinodes at BOTH ends closed = node at the closed end and antinode at the open end. B/c of this, closed pipes MUST only have odd harmonics (ie n = 1,3,5 etc)

mutually exclusive outcomes are?

outcomes that cannot occur at the same time (you canNOT flip BOTH heads and tails in one throw) the probability of 2 mutually exclusive outcomes occuring TOGETHER is 0%

Circularly polarized light

rarely seen natural phenomenon that results from the interaction of light w/ certain pigments or highly specialized filters it has a uniform amplitude but a continously changing direction which causes a helical orientation in the propagating wave the helix has average electrical field vectors and magnetic filed vectors taht lie perpendicular to one another, like other waves maxima fall on the outer border of the helix

What is it important to remember in estimating? DO NOT UNSTAR THIS

remember whether the rounded numbers are smaller or larger than the original number if one number is rounded UP, it is best (if possible) to: 1) Multiplication: round the other number DOWN slightly to compensate 2) Division: round the other number UP as well :) If the answer choices are VERY far apart (say by powers of 10) we can adjust the numbers so that one contains only one significant digit (ie 3.17 e4 x 4.53 e5 can be rounded to 3 e4 x 4.5 e5)

Streamlines

representations of molecular movement. They indicate the pathways followed by tiny fluid elements ('fluid particles") as they move. The velocity vector of a fluid particle will always be tangential to the stremline at any point Streamlines never cross each other

what uses fusion and how?

sun uses fustion by fusing 4 hyrdogen nuclei to make 1 helium nucleus and 2 hydrogens again as byproducts it makes 3.82 e26 J/second which accounts for the mass defect that arises from the formation of helium from hydrogen

Confidence (statistics)

the probabiliyt of correctly FAILING to reject a null hypothesis reporting no difference btwn 2 populations when one actually does not exist should be above 95%

timbre and natural frequencies. what are they when is it good, when is it bad/ another name for natural frequencies/

the quality of sound. it is determined by the natural frequency (aka resonant frequency) or frequencies of the object. Some objects vibrate at a single frequency, producing a pure tone = good Some objects vibrate at multiple natural frequencies (a FUNDAMENTAL PITCH and multiple OVERTONES) = even better/richer/fuller :) Some objects vibrate at multiple frequencies that have no relation to one another= bad/meh :/ (ie crumpling paper)

law of reflection

theta = MEASURED FROM THE NORMAL

what 2 types of sinusoidal waves are there? What are the highs and lows of them called?

transverse (has crests and troughs) longitudinal (has compressions and rarefactions = decompressions)

Lens makers equation what is it used for?

used for lenses where the thickness cannot be neglected. 1/f = (n - 1) (1/r₁ - 1/r₂) n = index of refraction r₁ = radius of curvature for the 1st lens surface r₂ = radius of curvature of the 2nd lens surface

how does doppler ultrasounds work/

used to determine flow of blood w/in the body by detecting the frequency shift associated w/ movement toward or away from the reciever

In the MCAT, should we worry about viscosity?

viscosity should be assumed to be negligible, thus allowing Bernoulli's equation to be an expression of energy conservation for flowing fluids

What happens w/ dielectrics in isolated capacitors

when a dielectric material is placed in an ISOLATED, CHARGED capacitor (a charged capacior that is disconnected from any circuit), the voltage across the capacitor decreases. This results from the dielectric material shield the opposite charges from each other. By lowering the voltage across a charged capacitor, the dielectric has INCREASED the capacitance of the capacitor. Thus, when a dielectric material is introduced into an ISOLATED capacitor, the increase in capacitance arises from a DECREASE in VOLTAGE

rectilinear propagation

when light travels thru a homogenous medium ,it travels in a straight line

Q314: Prometium-146 beta decays as follows: ¹⁴⁶₆₁Pm → ??Y + β⁻ what is the mass number and atomic number of Y?

¹⁴⁶₆₂Y

Change in entropy equation∙

ΔS = change in entropy = J/mol∙K Q,rev = heat gained or lost in a reversible process T = temperature in KELVIN

Parallel plate capacitance

ε₀ = permittivity of free space = 8.85 e-12 F/m A = area of overlap of the two plates d = separation of the two plates

√2 =? √3 =?

√2 =1.41 √3 = 1.73

When water melts from ice to water, what increases? What stays the same?°

#microstates permitted increases ie instead of only being ablte to move up and down or something, the ice can now rock back and forth/side to side, etc THAT SAID, now that it can do all these motions, the amount of up/down movement it has must decrease, thus the AVERAGE KE of liquid water at 0°C = AVERAGE KE of ice water at 0°C

pH = ?

-log(H)

What is the base units for watts

1 watt = 1kg∙m²/s³

Q22, A ball is thrown vertically up in the air from a window ledge 30m above the ground with an initial velocity of 10m/s.... 1) what is the velocity and position of the ball after 2 seconds? 2) What is the distance and time at which the ball reaches its maximum height above the window ledge

1) -9.6m/s, 0.4m 2) 5.1m, 1.02s

Q24, A projectile is fired from ground level with an initial velocity of 50m/s and an initial angle of elevation of 37°. Note, sin 37 = 0.6 and cos 37 = 0.8 1) What is the projectiles total time in flight 2) What is the total horizontal distance traveled

1) 6s 2) 240m

What are Newton's three laws

1) An object at rest or in motion w/ constant velocity will remain that way unless acted upon by a net force 2) An object of mass,m, will accelerate when the vector sum of the forces results in some nonzero resultant force vector (F = ma) 3) To every action, there is always an opposed but equal reaction (F,a->b, = -F,b->a,)

Given: 1) V₁, V₀ and a what is t? 2) Given V₀, t, and a... what is x? 3) given V₀, a, and x... what is V₁

1) V₁ = V₀ +at 2) x = V₀ (t) + 1/2 at² 3) V₁² = V₀² + 2ax

How does fluorescence work

1) excite fluorescent substance w/ UV radiation 2) the UV radiation excites the e- to a higher energy state 3) the e- returns to its original state in TWO OR MORE steps (ie has 1+ intermediates) -each step involves less energy so at each step, a photon is emitted w/ lower frequency (longer wavelength) than the absorbed UV photon if the wavelength of the emitted photon is w/in the visible range of EM spectrum, it will be seen as light of the particular colr corresponding to that wave length

In a population, 10% has diabetes, 30% is obese, 7% has diabetes AND is obese Are the events independent? What is the probability of a person being obese, or having diabetes or both

1) is it independent? NO. for it to be independent, P(A and B) = P(A) x P(B) = 0.1 x 0.3 = 0.03 <- probability of being fat and having diabetes IF they are independent events BUT the ACTUAL probability of having both is 0.07, so they are not independent 2) probability of having one or the other or both: 0.1 + 0.3 - 0.07 = 0.33 (33% chance of having at least one condition

What are 2 conditions at which an object is in rotational equilibrium?

1) object is not rotating 2) object is rotating with a constant angular velocity

3 rules for ray diagrams w/ lenses

1) ray parallel to the axis = refracts thru focal pt of front face of lens 2) ray thru or toward focal pt before reaching lens = refracts parallel to axis 3) ray to center of lens = continues straight thru w/ no refraction

What are the 4 fundamental forces of nature? What is the strongest? what does the weak version of it do/

1) strong nuclear force 2) weak nuclear force (contributes to stability of nucleus, but only about 1 millionth as strong as strong nuclear force 3) electrostatic forces 4) gravitation

Q312: Uranium 235 absorbs a low energy neutron and undergos fission, briefly forming an excited state of U-236 which then splits into xenon-140, strontium-94, and more neutrons, the unbalanced reaction is ²³⁵₉₂U + ¹₀n → ²³⁶₉₂U → ¹⁴⁰₅₄Xe +⁹⁴₃₈Sr + ¹₀n When balanced, how many neutrons are produced in the last reaction? Why is this good?

2 nucleons BUT, since protons are all balanced, these remaining nucleons are both neutrons.. these netrons are free to go on and be absorbed by more U-235 and cause more fission reactions

Potential difference?

Because electrical potential is inversely proportional to the distance from the source charge, a potential difference will exist between two points that are at different distances from the source charge. If V,a, and V,b, are the electrical potentials at points a and b, respectively, then the potential difference between them, known as voltage, is V,b, - V,a, SO: ΔV = V,b, - V,a, = W,ab, / q where W,ab, = work needed to move a test charge, q, through an electric field from point a to point b

What is confounding?

Confounding, sometimes INACCURATELY called confounding bias or omitted variable bias, is a data analysis error. The data may or may not be flawed, but an incorrect relationship is characterized. Ex: example of "When people eat more icecream they are more likely to drown" confounding variable = summer (ppl eat icecream AND swim in the summer, but the two aren't related

What is dE equal to when forces ARE conservaitve? What about when forces are NONconservative, what is dE equal to

Conservative: dE = 0 = U + K Nonconservaitve dE = W,nonconservative, = U + K SO the work done by nonconservative forces is equal to the change in mechanical energy "lost from the systme"

Electrical potential. Definition Equation (2) Scalar or vector? Sign conventions? for collections of charges?

Definition: the ratio fo the magnitude of a charge's electrical potential energy to the magnitude of the charge itself Equation ΔV = U/q = kQ/r Units: V = volts =J/C It's scalar. The sign is determined by the sign of the source charge, Q. For a positive source charge, V is positive For a collection of charges, the total electrical potential at a point in space is the scalar sum of the electrical potential due to each charge

Q 169: Suppose a proton is moving with a speed of 15m/s toard the top of the page (↑) THROUGH a uniform magnetic field of 3.0T directed INTO the page What is the magnitude and direction of the magnetic force on the proton. Describe the motion that will result from this set up NOTE: proton mass =1.67 e-27 e = 1.6 e-19C

F,B, = 7.2 e-18N Direction use right hand rule. Thumb points up (v), 1st finger points into page (F,B,), 2nd finger (to the left) Since v and F,B, are perpendicular, this implies that uniform circular motion will occur in this field w/ F,B, poingting radially inward toward the center of the circle. If the centripetal force is the magnetic force we can set these two equations equal to each other: F,c, = F,B, mv² / r = qvB sinθ ....AND...sin θ = sin 90 = 1 r = mv / qB = 5.2 e -8 m Thus the proton will move in a circle with the radius of 52nm

Q116: A window measures 2m x 3.5m. If a storm passes and lowers the pressure outside the window to 0.997atm while the pressure inside the building remains at 1atm. What is the net force pushing on the window?

F,net, = P,net,A =(P,outside, - P,inside,)A =(1atm -0.997atm)(1.013e5 Pa / 1atm)(2.0m x 3.5m) =2128N

T/F: flow rate can be different in a closed system at different points

FALSE, flow rate (volume/unit time) is constant for a closed system and is independent of changes in cross sectional area ie if we have water flowing through a pipe, the same amount of water will flow through 1cm³ in 1s as it will through 1cm³ in 1s further downstream in the pipe. even if the pipe gets wider or more narrow

T/F: To get a charge from one equipotential line to the other with the LEAST amount of work possible, you should take the shortest route

FALSE, the route doesn't matter b/c electrostatic forces are conservative so to get from one equipotential line to the other is going to be the same work no matter what the path is

T/F: scalars can NOT change the direction of a vector

FALSE, they CAN change the direction.... ie 3(A) = a vector 3 times as long as A. BUT -3(A) = a vector 3 times a long in the OPPOSITE direction

Do simple machines reduce the work that must be done?

NO, it reduces the force but does not magically chane the amount of work neceassary to move an object... displacement is pathway independent so the actual distance travedl from initial to final position does NOT matter, assuming all forces are conservative. therefore, appying less force over greater distance to achieve the SAME displacemnt (change in position) acomplishes the SAME amount of work

Capacitance General Equation and units

SI unit of capacitance = farad = C/V

pressure equation? Conversion between Pa, mmHg, torr, and atm?

SI units = Pascal = 1N/m² 1.013e5 Pa = 760mmHg = 760torr = 1atm

Q115: Find the specific gravity benzene, given that its density is 877kg/m³

Specific gravity = density of benzene/density of water Convert density of benzene to g/cm³ SG = ρ / (1000kg/m³) = 877/1000 = 0.877

Zeroth law of thermodynamics

States that when 1 object is in thermal equilirium w/ the other and the SECOND object is in thermal equilibrium w/ a third. then the FIRST and the THIRD are also in thermal equalibrium (IF A = B and B=C then A = C)

T/F: Linear speed can be different in a closed system at different points what is linear speed?

T, linear speed of the fluid DOES change relative to cross sectional area Linear speed is a measure of the linear displacement of fluid particles in a given amount of time

Absolute zero of celcius?

-273

What is the relationship of static friction? What does this mean?

0 </= f,s, </=u,s,N the force of static friction (f,s,) is greater than or equal to zero the force of static friction is less than or equal to mu of static friction times the normal force this means that EVEN IF the MAXIMUM static force of friction is 100N, if you are pushing with a force of 25N, the force of friction is still 25N, NOT 100N

Any exponent to the power of 0 is? (ie x⁰)

1

What are the 3 types of reversible?

1) Physics reversible: physicists define reversible processes as processes that can spontaneously reverse course. 2) Chemically reversible: processes that CAN be undone chemically For a chemicist, ice melting IS reversible process. For a physicist, ice melting is NOT a reversible process b/c it would never happen SPONTANEOUSLY 3) no reaction is truly reversible, bc some energy is always lost. A reversible reaction would require an infinite amount of time so that the system is always in equilibrium and no energy is lost. (idk actually how this works, look at p98)

What are the 3 pillars of research ethics according to the Belmont Report

1) Respect for Persons = 2) justice 3) beneficence

Taking the square roots of scientific notation: ie √4.9 e -7 is?

1) adjust notation so decimal pt is one over √49 e-8 = 7 e-4

Kirchoff's 2 laws = ?

1) at any pt or junction in a circuit, the sum of currents directed into the pt equals the sum of currents directed away from the pt 2) around any closed circuit loop, the sum of voltage sources will always be equal to the sum of voltage (potential drops).... ie: once you go around the loop, V = 0

Work, define all terms

W = Fdcosθ theta = angle btween applied force vecor and the displacement vector

standard deviation (4 steps) relation to outliers?

1. take the difference btwn eacy data pt and the mean 2. square each of these values 3. divide the sum of all of these squared values by n-1 4. take the square root of the result if a data pt falls more than 3 standard deviations from the mean, it is considered an outlier

16² 17² 18² 19²

16² = 256 17² = 289 18² = 324 19² = 361

angstrom to meter

1A = 10⁻¹⁰m

What is the conversion rate of Angstroms to meters? nanometers to meters?

1Angstrom = 10⁻¹⁰m 1nm = 10⁻⁹m

What is the base units of a Joule

1J = 1 kg∙m²/s²

What are the frequencies we can hear in/

20Hz - 20,000 Hz high frequency hearing gnerally declines w/ age

Calcualte the standard deviation of: 1,2,3,9,10

4.18

gamma decay

= emission of γ RAYS γ rays = high energy (high frequency) photons. they carry no charge and simply lower the energy of the parent nucleus w/o changing the mass OR atomic number The high energy state of the parent nucleus may be represented by an asterisk *

How would you subtract vectors (ie A-B)

A - B = A +(-B)... just add the -B vector

Sound level definition equation variables units

A logarithmic scale used to measure sound (b/c the range of human hearing is crazy wide so expressing it linearly is unmanageable β = sound level = measured in decibles I = intesnity of the sound wave (W/m²) I₀ = threshold of hearing (1 e-12W/m²)

Newton's Second Law

A non-zero net-force causes an object to accelerate in the direction of that force (F=ma)

Multiplication by a NEGATIVE scalar will give (i.e. -3(5jhat))

A resultant vector that is ANTIparallel to the original vector (-15jhat)

Amplitude is related to ____ (which is NOT the same as ____) Frequency is related to ____

Amplitude is related to sound level/volume (NOt the same as intensity) Frequency is related to pitch

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Magnetic field of a current carrying wire in a CIRCULAR LOOP.. when can this be used?

B = μ₀I / 2r Can ONLY be used in the CENTER of the current loop r = radius of current carrying loop

Magnetic field in a straight wire Equation variables direction

B = μ₀I / 2πr B = magnetic field at a distance, r, from the wire μ₀ = permeability of free space (4π e-7 Tm/A) I = current r = distance from wire to determine the direction of the field vectors, use a right hand rule = point your thumb in the direction of the current and wrap your fingers around the wire, this is the direction of the field lines

Pressure on us is ?

Countless trillions of air molecules are exerting tremendous pressure on our bodies w/ a total force of about 2 e5 N we don't actually feel all of this pressure b/c our internal organs exert a pressure that perfectly balances it

Q, What are the magnitudes and directions of the resultant vectors from the following cross products C = A x B D = B x A Where vector A = -3i and vector B = +4j

C = A x B = |A|x|B|sin(90) = (-3i)(+4j)(1) = -12k D = B x A = |B|x|A|sin(90) = (+4j)(-3i)(1) = - (-12k) = +12k

What are 4 types of PE?

Chemical PE Electrical PE Gravitational PE Elastic PE

What is the sine and cosine of the following angles 0 30 45 60 90 180

Cosine || sine 0 = 1 || 0 30 = √3/2 || 1/2 45 =√2/2 || √2/2 60 = 1/2 || √3/2 90 = 0 || 1 180 = -1 || 0

How is a vector calculated from the product of two vectors?

Cross product (A x B)

What is the SI unit for Current? for amounts of substances? for Temperature? For luminous intensity? What is the symbol of each (ie meters = m)

Current = Ampere (Coulomb/second) = A Amount of substance = mole = mol Temperature = kelvin = K Luminous intensity = candela = cd

Electrical potential energy. definition and equation Sign conventions?

Definition: EPE is the work necessary to move a test charge from infinity to a point in space in an electric field surrounding a source charge Sign conventions If charges are like charges, then the potential energy will be POSITIVE If charges are unlike, then the potential energy will be NEGAVITVE

Under non ideal conditions what can we calculate? What is the general equation and also the equation specific to pulleys?

Efficiency = The amount of useful work generated by a machine for a given amount of work put into the system: General E = W(out)/W(in) Pulleys = (load)(load distance) / (effort)(effort distance)

How can you account for the internal resistance of a battery and why do you have to? equation and variables Will you on the MCAT?

Even the very sources of emf, such as batteries, have some small but measurable amount of internal resistance, r,int,. As a result,the voltage supplied to a circuit is reduced from its theoretical emf value by some small amount. The actual voltage supplied by a cell to a circuit can be calculated from: V = E,cell, - (i)(r,int,) V= voltage provided by the cell E,cell, = emf of the cell i = current thru the cell r,int = internal resistance NO, it will not usually be on the MCAT

Newton's Third Law

F (A on B) = -F (B on A)

What is the FINER method?

F = is it feasible I = is it interesting (ie to other scientists) N = is it Novel (has it been asked/answered before) E = is it ethical? R = is it relevant (ie outside the scientific community)

T/F: small changes in chemical structure only minimally impact light absorption and emission patterns

F, small changes (such as protonation and deprotonation, change in oxidation state or bond order, and others MAY cause dramatic changes in light absorption in a material

Equation for Archimedes' principle. Caveat

F,buoyancy, = ρ,fluid, Vg REMEMBER: it is the density of the FLUID NOT the density of the object

Coulomb's law Units?

Fc = N k = 9 e9 N∙m²/C²

Pascal's principle

For fluids that are INCOMPRESSIBLE (ie fluids whose volume cannot be reduced by any significant degree through application of pressure), a change in pressure will be transmitted UNDIMINISHED to every portion of the fluid and to the walls of the containing vessel

Kinetic friction

Friction when a force is applied to a moving object.

Static friction

Friction when a force is applied to an object but the object does not move. Always greater than kinetic friction for a given object.

Current equation units

I = ΔQ/Δt Current = Ampere = C/s

Q237: A detector w/ a Surface Area of 1m² is placed 1m from a blender. It measures the avg power of the blender's sound as being 10⁻³W. Find the intensity and sound level of the blender Find the ratio of intensities of the blender and a jet engine NOTE (β,jet, = 150dB)

Intensity = P/A = 10⁻³W/m² Sound level = 90dB ratio = 10⁶

Relative sound level

I,f, = final intensity I,i, = initial intensity

KE

KE = 1/2mv²

In a bar magnet, the field lines EXIT the ___ pole and enter the ____ pole

In a bar magnet, the field lines EXIT the NORT pole and enter the SOUTH pole

In general intermediate sized nuclei are _____ than very large or small nuclei

In general intermediate sized nuclei are more stable than very large or small nuclei

venturi flow meter

In this picture, the height at points 1 and point 2 is the SAME... the "h" in the picture is NOT the same as the h from Bernoulli's equation which is the avg height of the tube above a datum. In this case the ρgh is constant for both points The main pt of this picture is that, the cross sectional area decreases from point 1 to point 2 , the linear speed must increase according to the continuity of equation. Then, as the dynamic pressure increases, absoulte pressure must decrease at point 2. With a lower absolute pressure, the column of fluid sticking up from the venturi tube will be lower at point 2. This phenomenon is often called the Venturi effect

How do we figure out how much volume of an object will be submerged?

It is equal to their SPECIFIC GRAVITY :) ie. if an ice cube has a specific gravity of .92 then 92% of its volume is going to be submerged

Q201: Consider 2 resistors wired in parallel w/ R₁ = 5Ω R₂ = 10Ω. If the voltage across them is 10V, what is the current thru each of the 2 resistors?

I₁ = 2A I₂ = 1A

Units for heat? (3).. conversions?

Joule also calorie or Calories (kcal) 1 calorie = amount of heat needed to raise 1g H2o by 1°C 1Cal = heat needed to raise 1kg of H2O by 1°C 1cal = 4.184J 1Cal = 4184J

Units of Energy

Joules = (kg∙m²)/s²

Kelvin to celcius

K = C +273

Q51: A 15 Kg block, initially at rest, slides down a frictionless incline and comes to the bottom w/ speed of 7m/s... what is the KE of the object at the top and bottom of the ramp?

KE = 0J at top KE = 367.5J at bottom

KE of a photon equation.. variables, 2nd equation, and what it tells us

KE,max, = h*f - W W = work function of the metal in question = minimum energy needed to eject an e- W = h*f,t, this only tells us the MAXIMUM KE that a photon COULD have, in reality the KE could be any where from 0J to KE,max

Conservation of mechanical energy

KE₁ + PE₁ = KE₂ + PE₂

Log,a,1 = ? (log base a)

Log,a,1 = 0

Log,a,A = ? Log A x Log B = log (A/B) = Log (A^B) Log (1/A) =

Log,a,A = 1 Log A x Log B = Log (A + B) log (A/B) = Log (A-B) Log (A^B) = B log(A) Log (1/A) = - log(A)

Exponential decay

N = number of redioactive nuclei that have not decayed yet in a sample N₀ = # of undecayed nuclei at (t = 0) e = natural log number λ = decay constant t = time

Q272: A penny sits at a depth of 3.0m in water (n=1.33). An obeserver 1.8m tall stands 30cm from the edge of the pool. Suppose the penny is 10 farther from the edge of the pool than the first one (37cm). Will a light ray going from this penny to the edge o the pool emerge from the water?

NO the light ray is internallly reflected (θ,c, = 48.8 θ,penny, = 51 θ,c, < θ,penny, so internal reflection

Q25, a 5kg block slides down a frictionless incline at 30°. Find the normal force and acceleration of the block (note, sin 30 = 0.5...sin 60 = 0.866)

Normal force = 42.4N a = 4.9m/s²

Pressure

P = F/A

Sign conventions for mirror

POSITIVE / NEGATIVE o = +object in front of mirror / -object behind mirror (v. rare) i = +image in front of mirror (real) / -image behind mirror (virtual) r = +radius, mirror is concave (converging) / -radius, mirror is convex (diverging) f = +focal length, mirror is concave / -focal length, mirror is convex m = +m, image is upright (erect) / -m, image is inverted

Sign conventions for lenses

POSITIVE / NEGATIVE o = +object is on same side of lens as light source/ - object is on opposite side of lens from light source (v. rare) i = +image is on opposide side of lens from light source (real) / -image is on smae side of lense as light source (virtual) r = +radius, lens is convex (converging) / -radius, lens is concave (diverging) f = +focal length, lens is convex (converging) / -focal length, lens is concave (diverging) m = +magnification, image is upright (erect) / -magnification, image is inverted

What ae the units for viscosity?

Pa∙s = N∙s/m² Pascal-seconds

What is Q vs q?

Q = source charge (the thing creating the electric field q = test charge (a charge placed in the field)

How are linear speed and flow rate related

Q = vA Flow rate = linear speed * Cross sectional area

density

SI units are Kg/m³ can also use g/mL or g/cm³ REMEMBER: 1mL = 1cm³ BUT 1000L = 1m³

Resistance equation variables units conduction pathways

R = resistance ρ = resistivity (ohm-meter, Ω∙m) L = lenth of resistor A = cross-sectional area (the wider the area the less resistance, just like the wider the river, the less resistance to water flow.... this is because the increase in cross sectional area increases the number of pathways thru the resistor, called conduction pathways)

Equations relating focal length/image distance/object distance/radius/magnification

SAME AS THOSE FOR SPHERICAL MIRROR m = -i/o and equations in the picture

Q29, three people are pulling on ropes tied to a tire with forces of 100N, 150N and 200N as shown on the flip side (see other side of flash card).. find the magnitude and direction of the resultant force (note, sin30 = 0.5, sin60 = 0.866)

SEE ANSWER BELOW F = 23.2N θ = -60° (60° below the x axis)

Q31, two blocks are in static equilibrium as shown on the flip side... if the coefficient of static friction between block A and the surface is 0.2, what is the maxiumum mass of block B?

SEE ANSWER BELOW m,b, = 3.0kg

Q33, A seesaw with a mass of 5kg has one block of mass 10kg two meters to the left of the fulcrum and aanother block 0.5m to the right of the fulcrum (see flipside). If the seesaw is in equilibrium, 1) find the mass of block 2 2) find the force exerted by the fulcrum

SEE ANSWER BELOW mass = 40kg force of fulcrum = 550N

What is the difference, if any, between A - B and B - A in vector subration

Same magnitude, different direction

torque equation

T = Fd(sinθ)

Unpolarized light vs polarized light

The electric fields of unpolarized light waves exist in all 3 dimensions: the direction of the wave's propagation is surrounded by electric fields in every plane perpendicular to that direction. Polarizing light limits the electric field's oscillation to only 2 dimentions

Q98,2: What is the relationship between the entropy of a system and its surroundings for any thermodynamic process

The entropy of a system and its surroundings will never decrease; it will always eiter remain zero or increase

Power (basic)

The rate at which energy is transferred from one system to another P = W/t = ΔE/t (b/c work = the change in energy = ΔE Power is ALWAYS a measure of the rate of energy consumption, transfer, or transformation per unit time

Mechanical advantage

The ratio of magnitudes of the force exerted ON an object by a simple machine to the force actually applied on the simple machine: MA = F(out) / F(in) dimensionless b/c is a ratio

Total mechanical energy

The sum of an object's potential nad kinetic energies.. U = PE, K = KE

What does dielectric material mean? Why is it important

The term dielectric material is just another way of saying insulation. When a dielectric material (ie air, glass, ceramic, etc) is introduced btwn the plates of a capacitor, it increases the capacitance by a factor called the dielectric constant, κ

State functions

Thermodynamic properties that are a function of only the current equilibrium state of a system, such as: P, ρ, T, V, H, U, G, S =Pressure, density, Temperature, volume, enthalpy (H), internal energy (U), Gibbs fee energy (G), entropy (S Not measured by an integral

What are real images for mirrors? for lenses? How about virtual/

To identify the real side (R) remember that the real side is where the light ACTUALLY GOES after interacting w/ the lens or mirror. for mirrors, light is reflected and, therefore, stays in front of the mirror. Hence, for a mirror, the real side is in front of the mirror. For lenses, the light travels through the lens and comes out the other side, thus the real side is on the OPPOSITE side of the lens from the original light source REMEMBER: the real image is one you can cast on the screen

T/F: the sum of the voltage source in a circuit is NOT equal to the sum of the voltage drops in that circuit

True, it is NOT necessarily even. So while the voltage sources and voltage drops are equal in any CLOSED LOOP, this is not necessarily true for the entire circuit. For example, a 9V battery that powers 10 light bulbs in parallel has a 9V source and a 9V drop across each light bulb - a total of 90V of drop across all of the light bulbs combined

T/F: total distance can never be less than the total displacement

True. Displacement is the straight line route between two points, distance is always (=) or more

Q60: A lead ball (mass = 0.125kg) is thrown straight in the air w/ initial velocity = 30m/s.. Assuming no air resistance, find the work done by the force of gravity by the time the ball is at its maximum height

USE KINEMATICS to figure this out W,net, = K₂ - K₁ = 1/2mv² - 1/2mv² =-56.25J

Lens power Equation units explanation (what is used for near sighted vs far sighted

Units = diopters P = + for converging lenses (needed for farsighted ppl = hyperopia) P = - for diverging lenses (needed for ppl who are near sighted = myopia)

Q120: A hydraulic press has a piston of radius 5cm. A 45Kg weight rests on this piston. Another piston in contact with this system has a radius of 20cm. Taking g = 10m/s², what force is needed on the larger piston to keep the press in equilibrium

Use Pascal's principle: P = F₁/A₁ = F₂/A₂ F₂ = F₁ (A₂/A₁) = m₁g(πr₂²/πr₁²) = 7200N

Voltmeters are inserted __in parallel/in series__ and ideally have _____

Voltmeters are inserted in parallel and ideally have infinite resistance

Rules of exponents

WHEN BASE NUMBERS ARE THE SAME ONLY Multiplication of exponents = X³ × X² = X²⁺³ = X⁵ Division of exponents = X³ / X² = X³⁻² = X¹ Exponents to exponents = (X³)² = X⁶ Fractions = (X/Y)² = X²/Y² Negative exponents = X⁻² = 1/X² Fractional exponents = (X)^½ = √x

What are the units for Power?

Watt = J/s

What happens w/ dielectrics in circuit capacitors

When a dielectric material is placed in a charged capacitor w/in a circuit - that is, still connected to a voltage source - the charge onthe capaictor increases. The voltage must remain constant b/c it must be equal to that of the voltage source. By increasing the amount of charge stored on the capacitor, the dielectric has increased the capacitance of the capacitor. Thus, when a dielectric material is introduced into a circuit capacitor, the increase in capacitance arises from an increase in stored CHARGE

When light enters a medium w/ a HIGHER index of refraction it bends _away/toward_ the normal. When light enters a medium w/ a LOWER index of refraction, it bends _away/toward_ the normal

When light enters a medium w/ a HIGHER index of refraction it bends TOWARD the normal. -it is moving INTO a slower medium so it'll bend down toward the normal When light enters a medium w/ a LOWER index of refraction, it bends AWAY the normal

What is an object's terminal velocity/

When the drag force (the force due to air resistance) equals the force of gravity (ie the weight of the object)

Linear thermal expansion. equation? define variables and their units

When the termperature of an object changes, its length changes "a lot" (aLΔT) a = coefficient of linear expansion (units = K⁻¹) L = original length dT = change in temp

Electric dipole moment

Which way does the dipole point for PHYSICISTS: physicists = define the vector along the line connecting the charges (the dipole axis), with the vector pointing from the negative charge toward the positive charge units = debye => 1 D = 3.34 e-30 Cm

When resistors are in series, the voltage drop across each resistor will be (different/the same)... the current will be(different/the same) the resistance will (decrease/increase) with each additional resistor When resistors are in parallel, the voltage drop across each resistor will be (different/the same)... the current will be(different/the same) the resistance will (decrease/increase) with each additional resistor

Will be DIFFERENT for resistors in series (use V = IR to find the voltage for each resistor)... The current will be THE SAME the resistance will INCREASE w/ each additional resistor will be THE SAME for resistors in parallel.. the current will be DIFFERENT (use V = IR to find the current for each resistor) the resistance will DECREASE w/ each additional resistor (b/c regardless, you are still giving the current alternative pathways to flow thru)

In gaseous systems, what is work equal to? When is work positive in a gaseous system What is the PV graph, what is the x-axis and what is the y?....What is work? When is NO work done?

a combo of Pressure and volume work is POSITIVE, when work is done BY the gas (ie the gas expands and volume increases) PV graph => x axis = Volume, y axis = pressure in a PV grouph, the work is found by finding the area under the pressure volume curve IF VOLUME stays constant and just pressure changes (dV = 0) then NO work is done

Chromatic aberration

a dispersive effect w/in a spherical lens Depending on the thickness and curvature of the lens, there may be a significant splitting of white light, which results in a rainbow halo around images. this phenomenon is corrected for in visual lenses like eyeglasses and car windows w/ special coatings that have different dispersive qualities than the lens itself

Single slit equation: what does it tell us, what is it? variables?

a*sinθ = nλ a = width of slit θ = angle btwn the line drawn from the center of the lens to the dark fring and the axis of the lens n = integer indicating the number of the finge λ = wavelength of the incident wave this is ONLY the location of the DARK fringes the bright fringes are halfway btwn dark fringes

aberrations: what are they, when do they appear?

aberrations = imperfections in mirrors/lenses spherical aberrations and chromatic aberrations

Q117: A diver is 20m below the surface. What is the absolute pressure she experiences? What is the gauge pressure? Note: density of sea water = 1025kg/m³

absolute = P,atm, + ρgz = 3.02 e5 Pa Gauge = P,abs, - P,atm, = (3.02 -1.013) x 10⁵ = 2.01 e5 Pa

Convection:

transfer of heat by physical motion of a fluid over a material fluid can be liquid or gas

When will an object float/

an object will float if its average density is LESS than the average endisty of the fluid it is immersed in

Adhesion

attractive force that a molecule feels toward the molecules of some OTHER substance

What is electrolyic conductivty based on? How is it measured?

based on strength of a solution. concentration and conductivity are directly related but it also depends on the identity of the solutes (ie ionic vs nonionic) meaured by placing the soution as a resistor in a circuit and measuring changes in voltage across the solution.

Ohm's Law

basically sats that for a given magnitude of resistance, the voltage ddrop across the resistor will be proportional to the magnitude of the current

What are 3 ways that liquid can turn to gas?

boiling, evaporation, vaporization

what can plane polarized light be used for?

can be used to classify stereoisomers the optical activity of a compound, due to the presence of chiral centers, causes plane polarized light to rotate clockwise or counterclockwise by a give number of degrees relative to its concentration (its specific rotation) remember that enantiomers, as nonsuperimposable mirror images, will have opposite specific rotations.

Atmospheric pressure

changes w/ atitude but at sea level its 1atm

Torques that generate clockwise rotation are considered (+/-)? counterclockwise?

clockwise = - counterclockwise = +

Draw ray diagram(s) for concave mirrors

concave = converging also, if object is ON focal pt, the rays would run parallel and image is at infinity

What is u,s, (the coefficient of static friction) dependent on? Units?

depedent on the two materials in contact it is a unitless value

What does Reynold's number depend on?

depends on factors like size shape and surface roughness of any objects w/in the fluid

process functions

describe the path taken to get from one state to another ie: work and heat

How does IR work? UV-Vis?

determines chemical structure bc different bonds will absorb different wavelengths of ligth UV-Vis spectroscopy = takes IR one step further and looks at the absorption of ligth in the visible and UV range

Set up of EM waves

electric field and magnetic field are perpendicular to each other

Which nuclear reaction does not emit anything?

electron capture does not emit anything. it ABSORBS an electron fomr the inner shell

What is energy? Kinetic Energy Potential energy?

energy: system's ability to do work (ie to make something happen) KE = energy of motion (have mass and some SPEED, velocity doesn't matter/velocity vector doesn't matter) PE = energy associated w/ a given object's position in space or other intrinsic qualities of the system

morally relevant differences= What is this? What are some examples? Some NONexamples? Grey areas?

examples of morally relevant differences = diferences btwn individuals that are considered appropriate reasons to teat them differently (ie age, population size - studies that impact large populations will generally have more potential to do good than ones that impact small populations) NOT morally relevant diffrences: race, ethnicity, sexual orientation MAYBE = religion (ie if certain interventions are prohibited by a given religion)

What is the equation for kinetic friction (f,k,)... what is it NOT dependent on

f,k, = u,k,N NOT dependent ofn how much surface area is in contact or even the velocity of the sliding object

Body temp in farenheit? celcius?

fahrenheit = 98.6 Celcius = 37

inviscid =?

fluids that have no viscosity... they are "ideal fluids" (ie like air, kinda)

What is the fundamental frequency vs 1st overtone for open pipes/strings?....harmonic series?

fundamenta frequency = first harmonic = lowest frequency of a standing wave that can be supported in a given length of string 2nd harmonic = 1st overtone harmonic series = all the possible frequencies that a string can support

What is the fundamental unit of charge? What is the WI unit of charge?

fundamental unit = e = 1.6 e-19 C SI unit = Coulomb

What is the conversion of gas -> solid

gas -> solid = deposition solid -> gas = sublimation

what is gigameters to meters/ megameters to meters? micrometers nanmeters picometers

giga = 10⁹ mega = 10⁶ micro = 10⁻⁶ nano = 10⁻⁹ pico = 10⁻¹²

range = affected by what?

heavilty affected by the presence of data outliers if you can't calculate standard deviation for a NORMAL istribution b/c the entire data set is not provided ,it is possible to approximate the standard deviation as 1/4 the range

Half life

in a sample of radioactive particles, the half life (T₁/₂) of the sample is the time it takes for 1/2 of the sample to decay. In each subsequent half life, one half of the remaining samle decays so that the remaining amount asymptotically approaches zero

internal validity and external validity

internal = support for causality external = generalizability to targe populations

what does a sigmoidal graph look like?

it looks like the blue line

Justice:

justice in selection of a research topic and execution of the research. it is based on morally relevant differences. Also: when there is risk associated w/ a study, distribute it evenly.. EXCEPT: sometimes, if one group may benefit more they will have to accept GREATER risk than those who may not benefit at all (ie maybe control groups?)

plane polarized light

light in which te electric fields of all the waves are oriented in the same direction (tht is, their electric field vectors are parallel) it follows that their magnetic field vectors are also parallel, but convention dictates that the plane of the electric field identifies the plane of polarization

What causes ameniscus? What causes a backwards meniscus and which is concave vs convex?

meniscus = concave (like the one in the picture) = a result of adhesive forces being STRONGER than cohesive forces backwards meniscus = convex = when cohesion is greater than adhesion... you should read these from the top of the bump

What is solidification

liquid to solid (ada freeezing)

How do you convert natural log to common log?

log x ~ (ln(x) / 2.303)

what are sound waves that are lower/higher than the human hearing range called?

lower than 20Hz = infrasonic Higher than 20,000Hz = ultrasonic

Magnetic fields are created by what? SI units? other units?

moving charges SI unit = Tesla = T 1T = 1Ns/mC Also measured in gauss: 1T = 10⁴ gauss

solve log (m x 10ⁿ) ie logs of scientific notation

n + 0.m bc log(mx10ⁿ) = log (m) + nlog(10) = log (m) + n(1) = n + log(m) AND m = between 1 and 10 (so log is between 0 and 1) page 342

What is the fundamental frequency vs 1st overtone for closed pipes?

n = 1 = fundamental frequency n = 3 = 3rd harmonic = 1st overtone n = 5 = 5th harmonic = 2nd overtone

Standing wave (closed pipe): wavelength and frequency

n = 1,3,5,odd integers

Standing wave's wave length (string/open pipe) variables = ?

n = a positive nonzero integer taht is called the HARMONIC. the harmonic corresponds to the number of HALF wavelenths supported by the string L = length of string/pipe

Difference btwn a galvanic and electrolytic cell?

not really sure, but when cells are discharging they act as galvanic (voltaic) cells. when they REcharging they act as electrolytic cells

Ohmmeters are inserted __in parallel/in series__ and ideally have _____.. what do they measure?

ohmmeters are inserted at 2 pts in series w/ circuit element of interest and ideally have no resistance. should be used w/ the circuit turned off. they often have their own battery of a known voltage and then function as ammeters thru another pt in the circuit

Normal distribution and mean

on a normal distribution apprx 68% fall w/in 1 standard deviation 95% fall w/in 2 standard deviations 99% fall w/in 3 standard deviations

open boundaries vs closed boundaries examples

open = those that allow maximal oscillation and correspond to antinodes (ie open end of a pipe and the fee end of a flag closed boundaries = do not allow oscillation and correspon to nodes

How does fluid dynamics affect us as humans

our circulatory system is a closed loop that has a nonconstant flow rate (ie our pulse

pitot tubes

pecialized measurement devices that determine the speed of fluid flow by determining the differenca btwn the static and dynamic pressure of the fluid at given pts along the tube

what is the equipotential line that lies halfway betwen +q and -q What is the electric field at this pt. What direction does it pt?

perpendicular bisector of the diple. Electrical potential at any point along this plane is 0 (b/c the angle btwn this plane and the dipole axis is 90 and cos 90 = 0) The magnitude of the electric field on the perpendicular bisector of the dipole can be approximated as E = (1/4πε₀)(p/r³) the electric field vectors at the pts along the perpendicular bisector will point in the direction opposite to p (as definied by physicists)

Given the electric power formula, explain how power companies can manipulate voltage and current

power companies can manipulate these two values while keeping power constant. ie can increase current which results in a decrease in voltage or can increase voltage which results in a decrease in current Power lines are high voltage lines, which allows them to carry a a smaller current, thus decreasing the amount of energy lost from the system

Pie chart pros and cons

pros easy to look at cons can't display more than a few data points/categories doesnt give much information

EM spectrum from longest wavelength to shortest

radio waves, microwaves, IR, Visible Spectrum (ROY G BIV), UV, xrays, gamma rays

what are 3 measures of distribution

range interquartile range standard deviation

What are the 3 rules for drawing ray diagrams for mirrors

ray parallel to axis = reflects back thru focal pt ray thru focal pt = reflects back parallel to axis ray to center of mirror = relects back at the same angle relative to the normal

Real vs virtual images?

real = when light rays converge at the position of the image image is virtual if the light only APPEARS to be coming from he position of the image, but does not actually converge there

Black body

refers to an ideal absorber of all wavelengths of light , which would appear completely black if it were at a lower temperaure than its surroundings

Is density vector or scalar?

scalar

Is pressure vector or scalar?

scalar Remember, just b/c force is used in the equation (P = F/A) and force IS a vector, it is only the MAGNITUDE component that is used in the equation No matter where one positions a given surface, the pressure exerted on that surface w/in a closed container will be the same, neglecting gravity

How can you see if a force is conservative or not?

see the change in energy of a system in which the system is brought back to its oritinal set up: ie: gravity = drop an ball and bring it back = same GPE Electrostatic forces = go around a circuit once = same EPE Friction: push a box around a circle = USED UP ENERGY, NOT conservative Air resistance: drop a ball and pick it up again = air resistance USED energy, NOT conservative

Explain A*V = constant fluid continuity?

so basically area x velocity (of water moving) = a constant

Q234: A train traveling at 144km/hr is sounding its whistle at 1450Hz. What is the frequency heard by the stationary observer when it is moving toward the observer? Away?

speed of sound~340m/s convert speed of train to m/s Toward = 1643Hz Away = 1297Hz

Second law of thermodynamics (in terms of the "dynamics" part of thermodynamics) What can it be known as to help remember it?

states that energy spontaneously disperese from being localized to becoming spread out if iti is not hindered from doing so entropy! Aka "time's arrow" b/c there is a unidirectional limitation on the movment of energy by which we recognize before and after

What is the 3rd law of thermodynamics?

states that entropy of a perfectly organized crystal at absolute zero is zero

statistical vs clinical significance

statistical significance = you can prove that it is not the result of random chance. clinical significance: a notable or worthwhile change in health status as a result of an intervention ie: a decrease in systolic blood pressure of 1 mmHg could be statistically significant, however, it is not likely to change patient out comes thus is not CLINICALLY significant a study should have BOTH to provide justification for an intervention

bimodal distribution:

still may only have 1 mode strictly peaking if one peak is slightly higher than the other but still considered bimodal you can, if you choose, analyze as 2 separate distributions but not necessary

What two mediums can support standing waves?

string that is fixed at both ends pipe that is open at both ends pipe that is open at 1 end and closed at the other (the maths is different for these than pipes open at both ends)

Surface tension = ? Result of what?

surface tension = causes liquid to form a thin but strong layer on the surface it is a result of cohesion = the attractive force that a molecule of liquid feels toward other molecules of the SAME liquid Basically, molecules feel attracted to other molecules of the SAME liquid. this force is balanced out below the surface, but ON the surface, the molecules only have these strong attractive forces from the molecule below them which pulls the surface of the liquid toward the center. this establishes tension in the plane of the surface of the water; when there is an indentation on the surface then the cohesion can lead to a net upward force

Hydraulic systems

systems that take advantage of the near-incompressibility of liquids to generate mechanical advantage which allows us to accmplish work more easily by applying reduced forces

p value

te liklihood that your statistic was obtained by chance/that your null hypothesis is true for DIRECTIONAL alternative hypothesis = should be less than .05 = α = significance level for NONDIRECTIONAL alt. hypothesis = should be less than (α/2) = .025 on either side

mass defect: what is it

the actual mass of every nucleus (otehr than hydrogen) is actally slightly smaller than the sum of all the masses of the protons and neutrons this happens bc of E = mc²

What is an electron volt

the amount of energy gained by an electron accelerating through a potential difference of one volt

refraction definition what is the speed of light/

the bending of light as it passes from one medium to anther speed of light in vacuum = 3 e8 m/s

Dielectric capacitance

the capacitance due to a dielectric material C' = new capacitance w/ the dielectric present C = original capacitance

What is the normal force?

the component of force between two objects in contact that is PERPENDICULAR to the plane of contact between the object and the surface that it rests upon

Dielectric constant

the dielectric constant of a material is a measure of its insulating ability. a vacuum has a dielectric constant of 1 by definition since a dielectric material can never decrease the capacitnce, κ can NEVER be less than 1 (also b/c it can't be less than a vacuum) (κ,glass, = 4.7 etc)

What is current?

the flow of charge etween two points at different electrical potentials connected by a conductor

Type I error

the level of risk that we are willing to accept for incorrectly rejecting the null hypothesis ie the liklihood that we report a difference in btwn 2 populations when one does not actually exist This is α or α/2 (for nondirectional alt. hypothesis)

What is entropy?

the measure of the sponateous dispersal of energy at a specific temperature ie: How MUCH energy is spread out. how WIDELY spread out energy becomes in a process

Threshold frequency Work function

the minimum frequency of light that causes ejection of electrons aka f,T, it depends on the type of metal being exposed to radiation. the photoelectric effect is, for all intents and purposes, an all or nothing respons: if the frequency of the incident photon is less than the threshold frequency (f < f,T,) then no electron will be ejected b/c photons do not have sufficient energy to dislodge the e- from its atom. If f > f,T, then e- will be ejected and the maximum KE of the ejected e- will equal the difference btwn hf and hf,T, (so KE = h*f - h*f,T,)

Power (statistics)

the probability of correctly rejecting a false null hypothesis (reporting a difference btwn 2 populations when one actually exists Power = 1-β

What is specific gravity? What is it used for?

the ratio of the density of an object to the density of pure water at 1atm and 4°C which is 1g/cm³ It is used to see if objects will sink or float in water

What if an object is ON the focal pt of a converging mirror?

the reflected rays will be parallel and thus the image will be at infinity

viscosity... symbol? viscous drag

the resistance of a fluid to flow...η viscous drag: increased viscosity of a fluid increases its viscous drag, which is a nonconservative force that is analagous to air resistance. So fluids like water which are thin (compared to like molasses) have low viscosity AND objects can move thru them w/ relatively low viscous drag

Diffraction

the spreading out of light as it passes through a narrow opening or around an obstacle.

What is hydrodstatics?

the study of fluids at rest and the forces and pressures associated with standing fluids

Lorentz force

the sum of electrostatic and magnetic forces

For the fundamental frequency, what is the wavelength?

the wavelength for the fundamental frequency is 4 times the length of the pipe

Conservative forces are ____ and ____... give some examples of conservative forces (2) non conservative?

they are path independent and do NOT dissipate energy conservative = gravity and electrostatic force non conservative = friction and air resistance

Magnetic force (current-carrying wire)

this is the force of the magnetic field on a straight, current carying wire placed in a magnetic field I = Current L = length of wire B = magnitude of magnetic field theta = angle between L and B vectors Use RHR to figure out direction. REMEMBER: current is considered the flow of POSITIVE charge

In a prism, what color do you expect to be on the top? on the bottom?

top = red b/c it has the longest wave length and thus is refracted the least violet = on the bottom b/c shortest wavelength and thus refracted the most

Radiation

transfer of energy via electromagnetic waves... can transfer heat thru a vacuum how ovens usually work (some ovens = convection ovens and use radiation AND convection currents)

Which will ALWAYS be bigger: u,k, or u,s,

u,s, will always be bigger (objects will "stick" until they start moving, and hten will slide more easily over one another

Angular frequency equation (2) units?

units = radians per second ω= 2πƒ = 2π/T

examples of unpolarized light

unpolarized light has random orientation of its electric field vectors; sunlight and light emitted from a light bulb are prime examples

How do you calculate the decay constant?

use half life decay constant = λ λ = (ln2)/T.₅ = 0.693/T.₅ T.₅ = half life

How does ultrasound work/

uses high frequency sound waves (outside our hearing range) to compare relative densities of tissues in the body it has a transmitter that generates a pressure gradient. and a reciver that processes the reflected sound. B/c speed of wave and travel time is known, the machine can generate a graphical representation of borders and edges w/in the body by calculating the traversed distance

How do you calcualte the speed of sound?

v = √(B/rho) B = bulk modulus = a measure of the medium's resistance to compression. B increases from gas to liquid to solid rho = density of the medium b/c the bulk modulus increases disproportionaly more than the density as one goes from gas to liquid to solid, sound travels fastest thru solid and slowest thru gas

Critical speed equation

v,c, = critical speed N,R, = a dimensionless constant called Reynold's number η = viscosity of the fluid ρ = density of the fluid

doppler effect

v=speed of sound in medium Vd= speed of detecotr vs= speed of source top sigh towards, bottom sign away

Plane mirrors: real or virtual image? Appearance of image?

virtual image (b/c the rays of light just rebound parallel and thus never converge images appear to be the same distance behind the mirror as the object is in front of it think of them as spherical mirrors w/ infinite radius of curvature

What is weight? is it scalar or vector? Units?

weight is a measure of gravitation force.... it is a vector quantity, units = N

photoelectric effect

when light of a sufficently high frequency (typically blue to ultraviolet light) is incident on a metal in a vacuum, the metal atoms emit electrons

EMF what is it, units? what is it not?

when no charge is moving between the two terminals of a cell that are at different potential values, the voltage is called electromotive force (emf or ε) electromotive force is NOT actually a force, it is a potential difference (voltage) and, as such, has units of joules per coulomb 1V = 1J/C) think of emf as a "pressure to move" that results in current

What is uniform circular motion

when the SPEED of the object is constant (even though its going in a circle, so its "velocity" is not).... in uniform circular motion, the instantaneous velocity vector is always tangent to the circular path

dispersion

when various wavelengths of light separate from each other (ie dispersion of white light into its component colors using a prism

If the speed doubles, the KE of an object will _____ (assuming mass is constant)

will quadruple

In a closed loop process of a PV graph, what is work?

work = area inside the curve

Q315; AN excited parent isotope X* gamma decays into X which then undergoes positron emission to form Y which in turn alpha decays to Z. If Z is americium-241, what is X*?

work backwards Y = berkelium-245 (A = 97, Z = 245) Parent nucleus = Californium-245 (A = 98, Z = 245) X = ²⁴⁵₉₈Cf*

Q270: A penny sits at a depth of 3.0m in water (n=1.33). If an obeserver 1.8m tall stands 30cm from the edge of the pool, how close to the side can the penny be and still be visible

x = 37cm (remember, he is 1.8m above the water so 4.8m above the penny)

What are the equations for the center of mass?

x = m₁x₁ + m₂x₂ + m₃x₃ + etc / (m₁ +m₂ + m₃ + etc) y = m₁y₁ + m₂y₂ + m₃y₃ + etc / (m₁ +m₂ + m₃ +etc) z = m₁z₁ + m₂z₂ + m₃z₃ + etc / (m₁ +m₂ + m₃ +etc)

Q303: IF a blue light of f = 6 e14 Hz is incident on rubidium (W = 2.26eV), will there be photoejection of electrons? if so, what is max KE? Constants: h = 6.626 e-34 Js = 4.14 e-15 eV.s

yes, it will be ejected KEmax = .22eV

What are common hypothesis tests (2)?

z test or t test rely on standard distribution (z test) or t distribution (t test)

Provide a definition of the magnitude of velocity in terms of speed/displacement and explain what it means

|v| = lim (dx/dt) t->0 Means magnitude of velocity at a point isnequal to the instantaneous speed at that point

Snells Law

θ = w/ respect to the normal!!

What are the 4 core ethical tenets in medicine?

1) beneficence = obligation to act in the patients' best interest 2) nonmaleficence = obligation to avoid treatments or interventions in which the potential for harm outweighs the potential for benefit 3) respect for autonomy = the responsibility to respect patients' decisions and choices about their own healthcare 4) justice = responsibility to treat similar patients w/ similar care and to distribute healthcare resources fairly

Identify which type of observational study each of these experiments is: 1) A study in which 100 patients with lung cancer and 100 patients without lung cancer are assessed for their smoking history. 2) A study in which 100 smokers and 100 non-smokers are followed for 20 years while counting the number of subjects who develop lung cancer in each group. 3) Study to determine the prevalence of lung cancer in smokers and non-smokers at a given point in time.

1) case-control 2) Cohort 3) cross sectional

Q122: A wooden block floats in the ocean w/ half its volume submerged. Find the density of the wood ρ,b, Note: the density of sea water is 1025kg/m³

1) find The magnitude of the weight of the block of TOTAL volume, V,b, 2) Find the weight of the displaced seawater only half of the block is submerged so V,underwater, = 1/2V,b, density = 512.5kg/m³

2 differences btwn lenses and mirrors

1) mirrors reflect light, lenses refract it 2) mirrors have one surface to work w/ and 1 focal length. Lenses have 2 surfaces that affect light path and have 2 focal lengths which (for THIN SPHERICAL LENSES) are the same

Q84. A metal rod of length 2m has a coefficient of linear expansion of 10⁻⁶ K⁻¹. It is cooled from 1080°C to 80°C. What is the final length of the rod

1.998m

Q316: If the half life of a certain isotope is 4 years, what fraction is left after 12 years?

1/8

focal length/image/object length/radius relation

1/f = 1/o + 1/i = 2/r f = focal length o = object length i = image length r = radius if "i" is positive it is a real image and in FRONT of the mirror if "i" is negative it is virtual and thus BEHIND the mirror

Use the mirror equation for plane mirrors

1/f = 1/o + 1/i = 2/r AND r = ∞ AND f = ∞ (because the focal distances are infinitely large so: 1/∞ = 1/o + 1/i = 2/∞ = 0 1/o = -1/i which means that o = -i so the image distance (which is negative) implies it is virtual also, the virtual image is at a distance behind the mirror equal to the distance the object is in front of the mirror

Waht are the base units of Newtons?

1N = 1 Kg∙m/s²

What is the conversion from joules to electron volts? What is the symbol of electron volts

1eV = 1.6 e-19J

What are the boundaries of visible light?

400nm (violet) - 700nm (red)

Q283: IN a double slit experiment, what is the linear distance btn the 6th and 8th minima on a screen if the λ=550nm and slits are separated by .14mm and the screen is 70cm from the slits

5.5mm

Ammeters are inserted __in parallel/in series__ and ideally have ___ (2things) What if the current is too high (ie would overwhelm the ammeter), what can you do?

Ammeters are inserted in series and ideally have zero resistance and zero voltage drop across themselves if current is too high, use a special low resistance shunt in parallel w/ the ammeter to allow a reading

Which type of nuclear decay could be detected in an atomic absorption spectrum?

B/c gamma radiation produces EM radiation (rather than nuclear fragments), it can be detected on an atomic absorption spectrum

How do hydraulic systems work?

B/c: P = F₁/A₁ = F₂/A₂ then the force on a small area will be amplified on the cylinder with the larger area (though it will be exerted through a smaller distance)

Energy of a photon equation

E = hf E = energy of a photon of light h = placks constant = 6.626 e-34 Js f = frequency of light (can then find wavelength using c = fλ

What is Newtons law of gravitation? Explain any constants

F,g, = (Gm₁m₂)/r² G = 6.67 e -11 (N∙m²/kg²)

A + charge is attracted to a - one. the distance btwn them is doubled. How has the force of attraction changed?

Force is reduced to 1/4 the strength

Q118: How does gauge pressure relate to the pressure exerted by a column of fluid

Gauge pressure is equal to the pressure exerted by a column of fluid plus the ambient pressure above the fluid, minus atmospheric pressure. When the atmospheric pressure is the only pressure above the fluid column, then gauge pressure equals the fluid pressure

Given a dipole, what is the electrical potential, using approximation for distant points

If points are relatively distant from the dipole (compared to "d" = the distance between the 2 dipoles THEN we get V = kqd cosθ / r²

What are the two types of ways fluids can move? Define

Laminar flow: smooth and orderly, often modeled as layers of fluid that flow parallel to each otehr. The layers will NOT necessarily have the same linear speed. For example, the layer closes to the wall of a pipe flows more slowly than the more interior layers turbulent flow: rough and disorderly. Turbulence causes the formation of eddies which are swirls of fluid of varying sizes occurring typically on the downstream side of an object

Q94: A gas in a cylinder is kept at a constant pressure of 3.5e5 Pa while 300kJ of heat are added to it, causing the gas to expand from 0.9m³ to 1.5m³. Find the workd done by the gas and the change in internal energy of the gas

P is constant so work can be found w/ W PΔV 2.1e5J change in internal energy = dU = Q - W = 90kJ

Gauge pressure

Pgauge = P,abs, - P,atm, = (P₀ + ρgz) - P,atm, gauge pressure = difference btwn absolute pressure (say inside a tire) and the atmospheric pressure (ie the pressure outside a tire) ie, he gauge pressure is the amount of pressure in a closed space above and beyond atmospheric pressure

Positive vs negative controls placebo effect

Positive controls = positive controls are those that ensure a change in the Dependent variable when it is expected. In the development of the new essay for detection of HIV, for example, administering the test to a group of blood samples known to contain the HIV virus could constitute a positive control. Negative control = negative controls, in contrast, ensure no change in the dependent variable when no change is expected. With the same assay, administering the test to a group of samples known NOT to contain the HIV virus could constitute a negative control Also, we often us a negative control group to asses the placebo effect in drug trials. Placebo effect = an observed or reported change when an individual is given a sugar pill or sham intervention

Using the potential difference equation, describe sign conventions (p159)

Potential difference equation: ΔV = V,b, - V,a, = W,ab, / q SO: charges will try to move spontaneouselyin the direction that results in a DECREASE in electricla potential energy For a positive test charge, this means moving from a poisition of HIGH electric potential to a position of LOW electrical potential. The voltage: V,b, - V,a, is NEGATIVE Since q is POSITIVE (its a positive test charge) then W,ab, must be NEGATIVE (to yield an overall negative answer) which represents a decrease in electrical potential energy For a NEGATIVE test charge: it will move from low electrical potenial to HIGH electrical potential The Voltage, V,b, - V,a, is POSITIVE Since q is NEGATIVE (its a negative test charge) then W,ab, must ALSO be negative (to yield an overall positive answer) Again, the negative work indicates that decrease in electrical potential energy BASICALLY: positive charges will spontaneously move in the direction that DECREASES their electrical potential (NEGATIVE voltage). Negative charges will spontaneously move in the direction that INCREASES their electrical ponential (POSITIVE voltage), yet, in both cases, the electrical potential ENERGY is decreasing

Magnetic force definition equation variables direction

This is the force that is exerted when a charge moves in a magnetic field q = charge v = velocity that it move thru field w/ B = field theta = smallest angle btwn the velocity vector and the magnetic field vector Direction = RHR Thumb = thrust First finger = field lines seCond finger = Current

What are the 6 simple machines? What is mechanical advantage? What is a simple machine?

any device that allows for work to be accomplished through a smaller applied force is thus said to provide mechanical advantage . simple machines are designed to give mechanical advantage machines = inclined plane, wedge (2 merged inclined planes), wheel and axle, lever, pulley, screw (rotating inclined plane)

Q162: H2O has a dipole moment of 1.85D. Calculate the elctrical potential due to a water molecule at a pint 89nm away along the axis of the dipole Note: k = 8.99Nm²/C² 1 D = debye = 3.34 e-30 C∙m

b/c the question asks for the potential along the axis of the dipole, θ = 0. Substitute the values into the equation for the dipole potential and multiply 1.85D by 3.34 e -30 to convert it to Cm: V = (kqd cosθ)/r² = (kp cosθ) / r²

Q132: A bathroom 40m above the ground has its water supply enter the building at ground level thru a pipe w/ inner diameter of 4cm. If the linear speed at the ground floor is 3m/s and at the bathroom is 8m/s, determine the cross sectional area of the pipe in the bathroom. If the pressure in the bathroom is 3 e5 Pa, what is the required pressure at ground level

calculate cross sectional area in bathroom using continuity equation => 4.71 e-4 m² Pressure is calculated from bernoulli's equation => 7.2 e5 Pa

____ mirrors are converging mirrors ____ mirrors are diverging mirrors What about lenses?

concave mirrors are converging convex mirrors are diverging the opposite is true for lenses

damping definition it does NOT do what? aka?

decrease in amplitude of a wave caused by an applied or nonconservative force (ie friction) its actually kinda good b/c w/o it periodically varying force would continually add energy to the system and it would probably break it does NOT result in a decrease in frequency, just amplitude aka attenuation

When do we usually account for variables outside of just the ones we are testing (ie lifestylel variables like smoking or BMI; or age and gender)

during data analysis. Where we try to account for all the confounding variables

focal length for spherical mirrors equation

f = r/2 r = radius of curvature (it is the distance between C and the mirror

What are the 3 types of nucelar reactions

fusion: when small nuclei combine to form a larger nucleus fission: when large nucleus splits into smaller nuclei, spontaneous fission rarely occurs radioactive decay: naturally occuring spontaneous decay of certain nuclei accompanied by the emission of specific particles (alpha decay = emission of αparticles, beta decay = emission of β-particles, gamma decay = emission of γ RAYS)

Standard distribution

has a mean of 0 and a standard deviation of 1 can use it to get info about probability or percentages of populations ideally apprx68% of the sample/population will be w.in 1 standard deviation of the mean

what do controls help us prove?

help us prove causality (b/c we can say that w/ or w/o the dependent variable some thing happen but in the control it didn't

Q205B: A 3µF capacitor is connected to a 4V battery. If a piece of ceramic w/ dielectric constant κ = 2 is placed btwn the plates, find the new charge, capacitance, and voltage

here the voltage is held constant by a battery new voltage is still 4V new capacitance =6µF new charge = 24µC

sound in decibels

intensity of sound waves/ threshold of hearing( 1 x 10-12 Watts per meter squared)

What supports the theory of light as a wave?

interference

Why is the sky blue? Esp when radio waves are ALSO not absorbed by the sky but are 100% reflected

it is blue b/c is the least absorbed by atmospheric gases in the VISIBLE light range even if radio waves are 100% reflected, we as humans do not have the sensors to see them

Is electrostatic force conservative or non conservative? What does this mean

it is conservative.... the work that a field does only depends on the potentials at points a and b and is independent of the actual pathway taken between a and b

Doppler effect

it is the difference btwn the actual frequency of a sound and its perceived frequency when the source of the sound and the sound's detector are moving relative to one another If they are moving toward each other, the percieved frequency is GREATER than the actual frequency If they are moving apart, it is lower

Population vs sample... what is it called when you use the population? what about a sample?

population = complete group of every individual that satifies the attributes of interest. information that is calcualated using every person in a population = a parameter sample = any group taken from a population that does not include all individuals from the population (ideally random, though selecting from certain small subgroups may be permissible). Information about a sample is called a statistic W/ comparatively large or repeated samples, statistics can be used to estimate population parameters

semilog vs log log graphs

semi log = uses logarithmic scale on one axis log log graphs = use it on both ALWAYS CHECK both!! AXIS ON ALL UR GRAPHS

In a 45-45-90 triangle, what are the lengths of the 3 sides

side opposite 45° = 1 side opposite 90° = √2

In a 30-60-90 triangle, what are the lengths of the 3 sides

side opposite of 60° = √3 side opposite 30° = 1 side opposite 90° =2

Single blind vs double blind

single = the patient or the assessor is blinded double = the investigator, subject and assessor do not know

difference btwn a single slit and a slit w/ a lens

single slit = does not create fringes on a screen, tho light does spread out when a lens is introduced the additional refraction of light causes constructive and destructive interference, creating fringes

What is fluid dynamics? what 2 assumptions do we make when studying them?

study of fluids in motion simplifications that we make = rigid walled containers and uniform density of fluids

Besides resistivity, length, and cross sectional area, what else can affect the resistance of a material. why/how?

temperature: higher termperatures usually lead to greater resistance this is due to increased thermal oscillation of the atoms in the conductive material, which produces a greater resistance to electron flow (some don't always follow this rule

when is radius (r) and focal length (f) positive for mirrors and lenses

they are + when mirrors and lenses are converging (concave mirrors and convex lenses) they are - when mirrors and lenses are diverging (convex mirrors and concave lenses)

What is Hill's criteria: what is it used for? What are they (9).. are all necessary?

used to determine the likelihood of causality in a relationship (only the FIRST is TRULY NECESSARY, but it is NOT sufficient by itself) 1) Temporailty - exposure (independent variable) MUST occur before the outcome (dependent variable) 2) Strength - when more variability in the OUTCOME/DEPENDENT variable is explained by variability in the INDEPENDENT variable = good 3) dose-response: as amount of independent variable increases, there is an increase in dependent variable response 4) Consistency - the relationship is found to be similar in multiple settings 5) Plausibility - there is a reasonable mechanism for the relationship (w/ existing literature) 6) Consideration of alternate explanations: If all other plausible explanations have been eliminated, the remaining explanation is more likely 7) Experiment: if an experiment can be performed, a causal relationship can be determined conclusively 8) Specificity: the change in the outcome variable is ONLY produced by changes in the independent variable 9) coherence: the new data and hypothesis are consistent w/ the current state of scientific knowledge

Type II error

we incorectly fail to reject the null hypotheiss ie the liklihood that we report NO difference betwn 2 populations when one actually exists the liklihood of a type II error occurring = β

What is the focal length of a multiple lens system where the lenses are in contact w/ each other? the power? example

¹/f,equ, = ¹/f₁ + ¹/f₂ + ¹/f₃ + etc P,equ, = P₁ + P₂ + P₃ +etc example = contact lens that is in direct contact w/ the eye the eye is a converging lens, the contact lens can be either depending on the necessary correction their powers would be added

Torque on a dipole in an electric field

τ = pE sinθ p = magnitude of dipole moment = qd E = magnitude of the uniform external electric field θ = anlge the dipole moment makes w/ the electric field

What is the equation of torque?

τ = r x F = rF sin(θ) r = length of the lever arm F = magnitude of the force θ = angle between the lever arm and the force vectors KNOW WHAT THETA IS!!! (ie you have to translate the force vector, just look it up)

Isothermal process

A process that occurs at constant temperature (ΔU = 0)

Q62: A block weighing 100N is pushed up a frictionless incline over a distance of 20m to a height of 10m. A) What is the minimum force required to push the block? B) the work done by the force C)The force required and the work done by the force if the block were simply lifted vertically 10m

A) min force needed to push block up w/ no acceleration = force of gravity parallel to the inclined plane = Fg = mgsin(θ) = 100(10/20) = 50 B) work = Fdcosθ (where θ = angle btwn force and displacement vectors, in this case θ = 0, cos θ = 1) W = (50N)(20m)(1) = 1000J C) Force up = gravitational force = 100N Work = Fdcosθ = 100N (10m) (cos0) = 1000J