INDEX + Definitions, Laws,…
and other things; on my screen they are all one-liners

Below, look things up alphabetically. If you want to begin studying physics, go here, where my e-book starts in mechanics. Or if you already know about forces and motion, you may want to go to fluids, heat, electricity and magnetism, or waves or quantum effects.

Page down a few times, or choose the first letter of the word you are looking for: Bb Cc Dd Ee Ff Gg Hh Iiii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww xyz. If you look something up here, you will find a very brief line about the topic, just enough to get you started (or to turn you off, I hope not). In many cases, a link is provided to more stuff I have written about the topic.

See if ctrl-home gets you back to the top.
Here and there in this document, a single letter is linked to its alphabetical home, if you know what I mean.

Note: Your browser might show capital delta as D, pi as p, etc. If a , b look like a, b, then your browser does not recognize Greek letters, and this could cause confusion.

An asterisk (*) in front of a line means you probably need to know it well.

*a: symbol for acceleration, the rate of change of velocity, Dv/Dt or dv/dt

a: also the symbol for the semimajor axis of an ellipse

a: atto: 10^-18

A = area

A = amplitude, height of a wave from the equilibrium point

aberration: distortion of image because lenses are not perfect

A-bomb: neutron induces U nucleus to split, releasing more neutrons, splitting more U nuclei

absolute pressure P: the zero pt is the unattainable perfect vacuum; see gauge pressure

*absolute temperature T: the zero point is the unattainable absolute zero; see Celsius

absolute zero unattainable? Can we be certain of anything? -273.15 ^oC

ac: alternating current; in the US, power companies use 60 Hz frequency

*acceleration: rate of change of velocity v; if constant rate of change, click linear

*acceleration due to gravity, g = 9.8 m/s² treated as a constant for most purposes

achromatic lens: a lens without chromatic aberration

*action-reaction: forces always occur in equal & opposite pairs so the sum of all = 0 in universe.

adiabatic process: no heat transfer

aerogel: least dense solid; best thermal insulator; fairly transparent; too expensive now

age of the universe: 13.7 billion years or so (billion = 10⁹ or Giga)

air: about 80% nitrogen and 20% oxygen

air resistance: we neglect it in elementary physics, but it can be important

albedo: the fraction of incident sunlight that a planet reflects

algorithm: an exact step by step plan to get a result

alkali metal: one more electron than a noble gas. Sodium,...

alpha decay: all nuclei heavier than bismuth could emit a

alpha particle: same as helium nucleus, 2 protons & 2 neutrons

alternating current: goes back and forth; in USA the standard is 60 Hz (see Hertz)

alternative fuels: hydrogen, ethanol, methanol, biodiesel... (Fossil fuels will be depleted.)

aluminium: aluminum in British-English-speak

aluminum: element with lucky atomic number 13; see aluminium

AM: amplitude modulation, usually in radio

ammeter measures amperes, but do not say amp-meter

*ampere (A): unit of current, 1 A = 1 coulomb/second

*Ampere's law: (not discovered by Ampere) magnetic field due to a current

amplifier: circuit to increase amplitude of a signal

*amplitude: maximum wave height measured from equilibrium or maximum voltage

amplitude in quantum mechanics is the square root of the probability

angstrom: unit of length = 10^-10 m, atom size

*angular acceleration a = a/r in radian/s² where a=acceleration and r=radius

*angular frequency w = 2p f in radian/s if f is frequency in Hz.

*angular impulse t D t = change of angular momentum

*angular momentum L = Iw or rx(mv): total is conserved if no external torque acts

*angular speed or angular velocity w = v/r in radian/s

antiparticles: same mass, opposite in other properties; every particle has an anti

API: application programming interface

*Archimedes' principle: buoyant force = weight of fluid displaced

area of circle: p r²; ellipse: p ab=p a²(1-e²)^1/2; surface of sphere: 4p r²

Aristotle's physics (by thought, not experiment) set back progress for many centuries. Great philosopher but..

ASCII silly question and you'll get a silly ANSI

asteroids: mostly between Mars & Jupiter; broken-up planet?

astrology: total nonsense; see Elvis sightings

atmosphere as a pressure unit: 1 atmos = P at sea level

*atmospheric pressure = 1.01 x 10⁵ Pa (pascal = Pa = N/m²), see newton (N)

atomic mass unit: 1 amu or u = 1.66x10^-27 kg, m of carbon 12 atom divided by 12

atto (a): 10^-18

aura surrounding a person: total nonsense; see Elvis sightings

*average velocity = distance/time [=(v_o + v)/2 if acceleration is constant]

Avogadro's number = number in a mole = 6.022137 x 10²³/mole

*B = symbol for magnetic field or flux density or magnetic induction (see tesla)

 B due to a segment of current is proportional to the sum of the cosines of the angles

B due to a coil anywhere on the axis: inside or outside a long or short coil

barn: 10^-28 m², =100 fm², about the cross-sectional area of a nucleus

baryon is made of 3 quarks; neutron and proton are examples

beard-second: length a beard grows in a second, 1 bs » 10^-8 m

BE condensate: Bose-Einstein condensate = atoms in one quantum state, like 1 atom

*beat frequency = D f when two frequencies mix

Bernoulli's principle: higher v means lower P under the right conditions

beta decay: electron or positron emitted from nucleus

Bethe cycle (stars):  overall, 4p forms 1 He + 2e⁺ + 2n + energy

Betz coefficient: 16/27, the maximum fraction of wind power that one can capture. Derive

big bang: about 13.7 billion years ago, all matter and energy created and Universe began

big crunch: universe collapses? The evidence says no, it will keep expanding.

billion: 10⁹ or giga in US and France; 10¹² in UK and Germany; thus avoid the term

binding energy per nucleon: iron nucleus has about the maximum

Biot & Savart law for calculating magnetic field from charge, velocity & distance

bit: 0 or 1 in a computer; byte = 8 bits

black body radiation: intensity is s T⁴, where s is 5.67x10^-8 W/(m^2× K⁴)

black radiates more and absorbs more

black hole: g super large-- light cannot escape; would be a handy trash can

blog = web log

Bohr-de Broglie hydrogen atom model: circular electron orbits quantized

Bohr magneton: 9.2740154 x 10^-24 J/T

Bohr radius, H atom, 1st orbit: 5.3 x 10^-11 m

*boil: liquid to vapor- heat required is L_v m; m = mass vaporized, L_v=constant

Boltzmann's constant k = gas law constant R divided by Avogadro's number

Boltzmann's constant k = 1.380658 x 10^-23 J/K

Boolean algebra: uses 0 & 1 only: 1+1=1; all other operations are as expected

Bose-Einstein condensation: gas of bosons all go into the lowest energy state

boson: particle with integral spin quantum number

*Boyle's law was first discovered by Towneley and Powers

Bq (becquerel) unit = 1 disintegration/second.  1 curie (Ci)=3.7x10¹⁰ Bq

Bragg equation is for x-rays reflected off a crystal, 2dsinq = ml for maxima

breeder reactor: unfissionable ²³⁸U converted to ²³⁹Pu, which is fissionable

bremsstrahlung: braking radiation; electron hits target, radiates electromagnetic waves

Brewster's law: tanq _p = n, where q _p = angle such that reflection is totally polarized

brewster's law: keep air away from the fermenting beer

British units: we blame the Brits for pound, slug, foot (sounds like martial arts)

Brownian motion: random motion of a particle in a fluid caused by molecules bumping it

buckyball (buckminsterfullerene): C_60, molecule of C atoms shaped like a soccer ball

bulk modulus B: pressurize something and it shrinks in volume: D P = -BD V/V

*buoyant force = weight of fluid displaced (Archimedes' principle)

buoyant force experiment

c = speed of light, nature's speed limit, 299,792,458 m/s ~ 3.00 x 10⁸ m/s

 calculus deals with infinitesimal quantities

*calorie: heat energy to raise temp. of a gram of water 1^oC; 1 cal = 4.186 joule

*Calorie (diet) = kilocalorie, 4186 J. 2000 diet Cal/day = 97 watts.

candela (cd): SI unit of luminous intensity, 1 cd = 1 lumen/steradian

*capacitance C= q/V, unit: farad = coulomb/volt, see capacitor

capacitive reactance, X_c = 1/(w C), opposition to AC in Ohms

*capacitor stores electric charge (batteries keep constant V, capacitors don't)

carbon cycle: see Bethe cycle

carbon dating: radioactive C created from regular C in atmosphere, used to find age of formerly living

carbon dioxide, atmospheric: 315 ppm in 1958, 377 ppm in 2004

carbon nanotubes: lots of future technology waiting to be developed

Casimir effect: two uncharged plates in a vacuum attract each other due to vacuum polarization

caterpallor: color of your face after seeing half a worm in your apple

*Celsius temperature scale: water freezes at 0^o C = 273.15 K, boils at 100^o C=373.15 K.

^oC = ⁵/₉(^oF + 40) - 40 and  ^oF = ⁹/₅(^oC + 40) - 40

center of buoyancy: buoyant force acts like one force at this point

center of gravity is center of mass for all practical purposes; weight is like one force

*center of mass x_cm = S mx/m_total

*centrifugal force: for this you need an accelerated reference frame; avoid it

*centripetal acceleration a_c = v²/r = w ²r

*centripetal force: avoid the term; no new force is present in circular motion

chaos: herding cats, for example

charge: the "stuff" of electricity, it is what is flowing in an electric current

charge of the electron: 1.6 x 10^-19 coulomb

chemical reaction: it's all in the electron configurations (nuclei do not change)

*circular motion: S F_c = mv²/r

circular reasoning: see reasoning, circular

clairvoyance: total nonsense; see Elvis sightings

cm: centimeter, CM: center of mass

CO₂, atmospheric: 315 ppm in 1958, 377 ppm in 2004; causes global warming

*coefficient of friction m : friction force = m times the normal force

cogeneration: produce electricity and instead of throwing out waste heat, use it

*coil, magnetic field of, or to find inductance of a coil, see inductance

cold fusion: maybe something, but not fusion; see Elvis sightings

*collisions: apply conservation of momentum and sometimes energy

color magnify the white on the computer screen and you will see red, green and blue

*components of a vector: vector = hypotenuse of right triangle, comps = other sides

Compton effect: a photon bounces off an electron; Compton derived the change of l

*concave mirror & convex lens: positive f; one equation is used for these and for

*concave lens & convex mirror: negative f

condensation: opposite of evaporation; same amount of heat transfer occurs

conductance: inverse of resistance; 1/ohm = mho

*conduction of heat: heat energy flows toward the lower temperature

*conduction of current: electric charge flows toward the lower voltage

conduction or flow of fluid: fluid flows toward lower pressure region

conductivity = inverse of resistivity. see resistivity

conic section = intersection of plane & cone: point, ellipse, parabola, hyperbola, straight line

consciousness: that annoying time between naps

conservation laws: in physics they are about quantities that are constant (see below)

*conservation of angular momentum (if no net external torque acts)

*conservation of charge (if no charge enters or leaves)

*conservation of energy (if no energy enters or leaves)

*conservation of momentum (if no net external force acts)

conserving energy resources: we're addicted to fossil fuels; will suffer withdrawal

conspiracy, Federal Government, 9/11/01: See Elvis sightings and get over it.

*constant acceleration problems: equations and how to use them

conundrum: use for safe lex

*converging lenses, mirrors: convex lens, concave mirror, positive f, converging type

*convex mirror, concave lens: negative f; diverging type: parallel rays diverge after

Copernicus theory (1543): planets orbit the sun

Coriolis effect makes a cannon shot go a little to the right in N. hemisphere, although…

…Coriolis force is a fictitious force on the cannonball. The effect is due to Earth's rotation.

*cosine: (side adjacent)/(hypotenuse) in a right triangle

cosine law can be used to add vectors

cosmic rays: particles from space, mostly from sun

cosmic background radiation:  microwave radiation from the big bang

cosmology: evolution of the universe; cosmetology: evolution of hairdos

cosmos: the whole shebang

*coulomb unit of charge: 1 C = 6.25 x 10¹⁸ e (e = absolute value of electron charge)

*Coulomb's law F = kq₁q₂/r² with k = 8.987552 x 10⁹ N× m²/C²

cracker: criminal hacker

crap game quantum mechanics: to illustrate some of the ideas and notation

creationism: total nonsense; see Elvis sightings

critical angle: sinq _c = 1/n, where n = index of refraction (see Snell's law)

crop circle hoax: people believed aliens landed; see Elvis sightings

Curie, Marie: Nobel Prizes in both chem and phys.

curie: (abbreviated Ci) Unit representing 3.7 x 10¹⁰ disintegrations per second, see Bq

*current (electric) I = q/t =charge which moves past a point in time t divided by t, see Ohm’s law

current events: lightning, for example

curve ball, due to Bernoulli effect?

curved space: the cause of gravity (in Einstein's general relativity theory)

 d: small D ; dx means small D x, so dx/dt is instantaneous speed

dark energy: unknown cause of expansion of universe speeding up

dark matter: Not visible, what is it? 95% of mass in the universe is unknown stuff

Darrieus wind machine: eggbeater-like blades, vertical axis

daughter nucleus: after a radioactive decay

DC: direct current goes one way (alternating current goes back & forth).

de Broglie theory: particle of momentum p has wavelength h/p; (see h, see p=mv)

decay of a radioactive nucleus: start with number N_o, then N = N_oe^-t/t ,t =mean life

*deceleration: slowing down; negative acceleration if velocity is positive

delusions of adequacy: thinking you can get along without physics

*density r = mass/volume

destructive interference: occurs where waves are out of phase

diamagnetism: weak repulsion of a substance from a magnet, an electron orbit effect

(paramagnetism is a weak attraction to a magnet, an electron spin effect)

diameter of proton: 2 x 10^-15 m

diameter of iron nucleus: 8 x 10^-15 m

diameter of typical atom: 1 x 10^-10 m

diameter of red blood cell: 7.5 x 10^-6 m

diameter of  Earth: 1.27 x 10⁷ m

diameter of our galaxy: 7.6 x 10²⁰ m

*dielectric constant and its effect on capacitance

*diffraction: through a double slit, grating, or a single slit

diode: one-way valve for electric current; pair of n&p-type semiconductors

diopter: meter^-1 If a lens has focal length f meters, then 1/f is the "strength" of the lens in diopters.

dipole: electric, magnetic (a pair of equal & opposite charges or poles)

Dirac delta "function"  d(x) such that ∫f(x)d(x)dx = f(0). d(x)=zero everywhere except =1/dx at x=0.

*direct current: I = q/t =charge which moves past a point in time t divided by t

dispersion or why there are rainbows

*diverging lens (concave lens) like convex mirror, both have negative focal length

Doppler effect: higher frequency if source is moving toward you or you toward source

double refraction: some crystals split a light beam into two, polarized ^

*double slit:  Interference maxima: dsinq = ml is a good approximation, click here for exact equation

down (quark, d): rest energy = 360 MeV, charge -¹/₃e

dowsing to find water: total nonsense; see Elvis sightings

dud: neutron is a dud, two down quarks and one up

*dynamics: applying Newton's laws

dynamo: produces electric current via Faraday's law

*1 dyne = the weight of a mosquito; dyn is the abbreviation, a great space saver

 e: 2.7182818284…, the base of the natural logarithm (ln); ln(e^x) = x, e^lnx = x

e: absolute value of the electron charge, e=1.602 x 10^-19 Coulomb

e: eccentricity of an ellipse- circle has e=0, long thin ellipse has e close to 1

e: efficiency of an engine: work out/fuel energy used

e: emissivity. blackest black e=1, absorbs all light, emits maximum infrared

E: electric field, (electric force vector on a small q) divided by q

E: energy, ability to do work (oversimplified definition)

E=mc² : mass-energy equivalence; i.e. mass is energy, energy is mass, but units differ. Derive it.

e/m: charge to mass ratio of the electron, 1.76 x 10¹¹ C/kg

Earth: R_orb=1.496x10¹¹m, r_E=6.371x10⁶ m, mass=5.974x10²⁴ kg, I=8.021x10³⁷ kg×m²

Earth: age 4.6 billion years, axis precesses with period about 26,000 years

Earth's period of rotation (day) increases 1.5 ms/century due to tides

eccentricity e of an ellipse: zero for a circle, almost 1 for a long, thin ellipse

eccentricity e of a hyperbola: e>1

eccentricity e of a parabola: e=1

eddy current: usually unwanted, but can be used to test for cracks in metals

*efficiency e of an engine: work output divided by fuel energy input; see heat engine

Ehrenfest's theorem in quantum mechanics is the Newton's 2nd law equivalent

eigenvalue: characteristic value.

Einstein: special relativity, general relativity, photoelectric effect (and many others)

*elastic collision, the ideal case, no loss of KE in the collision

elastic potential energy: deform something that "wants" to return to normal

electret is to electric field as permanent magnet is to magnetic field

electret example: melt carnauba wax, let it cool in an electric field

*electric charge: the "stuff" of electricity, + or -

*electric circuits: series and parallel and beyond

*electric current I = charge passing a point divided by time of passage

electric dipole: a pair of equal and opposite charges

*electric field E = force on a small test charge divided by its charge

*electric potential = voltage V, the potential energy of q divided by q

*electric potential energy = Vq (see electric potential, then see circular reasoning)

*electric power = VI = I²R = V²/R, watt = joule/second

electric vehicle: a green choice

*electromagnetic waves (radio, microwave, infra red, light, ultraviolet, x-ray, g ray)

electron: charge = -1.602177x10^-19 Coulomb, mass = 9.109390 x10^-31 kg

*electron-volt: unit of energy = 1.602177x10^-19 J (see electric potential energy)

electron wavelength = h/momentum, h = Planck's constant, 6.626 x 10^-34 J× s

electrostatics: static cling and all that

electroweak force: unification of the weak nuclear and electromagnetic forces

elliptical orbit of a satellite, and more than you wanted to know about it

Elvis sightings: believing in a falsehood because you want to believe it

emissivity: e=0 to 1, measure of radiation emission (and absorption)

*energy: ability to do work is the oversimplified statement of what it is

entropy: a measure of disorder; when things are a real mess, call it high entropy

*equilibrium: zero acceleration, so S F=0; zero angular acceleration so S t =0

equipartition of energy: for example in a solid, atoms have PE=KE

*erg: work done by mosquito doing a push-up, a dyn× cm

escape speed: (2GM/r)^1/2 = speed needed to escape a planet (not orbit)

*eV: electron-volt, PE change of electron moved through one volt, 1.6x10^-19 J

evaporation: fast molecules escape, reducing the average v of liquid molecules, lowering the temperature of the liquid

evolution "just a theory" is an admission of ignorance.  A theory is well-verified, the highest ideas of science.

exponential decay: capacitor voltage for example, V=V¥ +(V_o-V¥ )e^-t/RC

 f: symbol for force, frequency, farad; the context tells you which

factorial: 5!=5 factorial = 5x4x3x2x1=120. 0! is defined = 1

Fahrenheit temperature scale: freeze water at 32^o & boil at 212^o F

*farad (f): unit of capacitance; most capacitors are in the mf or pf range

*Faraday's law: induced voltage = rate of change of flux

femto (f): 10^-15

Fermi: should be pronounced fair-me (lots of people say fur-me)

fermion: particle with spin half h-bar (boson has integral spin number)

final theory: (dream on, Steve) if we find one we can't be certain that it's right, so…

fine structure constant = e²/(2e _o hc) » 1/137

*first law of thermodynamics is the conservation of energy principle

fish eyes have spherical lenses

fission, nuclear: split a big nucleus and energy is released; see fusion

flow of fluid, heat, charge: one equation fits all

*fluids main page includes heat and electricity which are like fluids in some ways

flux of a field: field times perpendicular area

forces of nature: gravitational, electromagnetic, strong & weak nuclear

forces, contin.: electromagnetic and weak nuclear unified= electroweak force

*force vectors: the vector sum of all µ ma (S F = ma for certain units)

fossil fuels are being used up. We will convert to solar energy dependence eventually

*free fall: acceleration g = 9.8 m/s² = 32ft/s² on Earth

*friction, static (no slide) and kinetic (sliding)

fuel cells will probably replace most batteries some day

fuse: (old word for melt) electrical safety device melts due to excessive current

*fusion, latent heat of: constant L_f in equation D Q=L_f m when m melts

fusion, nuclear: take little nuclei, stick 'em together to form larger; energy is released

fusion in music: take different kinds and stick 'em together

furlong = 1/8 mile = 220 yards

furlong/fortnight  = 1.66 x 10^-4 m/s

*g: acceleration due to gravity or gravitational field; g = GM/r²; weight is mg

*G: universal gravitation constant, 6.6726 x10^-11 Nm²/kg² , F=GMm/r²

Galileo did experiments and found that Aristotle had wrong ideas about physics

gamma: factor in relativity theory, g = (1 - v²/c²)^-1/2

gamma ray: electromagnetic wave from nucleus

gamma ray bursts: said to be the most energetic events in the universe; unknown origin

gas: molecules relatively far apart

*gas law about P, V and T (PV=nRT) or a more theoretical approach to the gas law

gasoline: energy content 132 MJ/gallon

gates: and, nand, or, xor, nor, Bill. Certain inputs yield a certain output

*gauge pressure: difference between absolute P and atmospheric P

gauss: 10^-4 tesla, magnetic field unit

Gaussian surface: imaginary surface around charge(s); elec flux thru it prop. to q inside

generator: application of Faraday's law

geosynchronous orbit: w of satellite = w of Earth's spin, 2p rad/24hr, altitude 22 k mi

geomagnetism must be due to two competing effects because sometimes fields reverse

*geometric optics: thin lenses, flat and curved mirrors, one equation fits all

geysers work like coffee percolators

gibbous moon: between half & full

*gigahertz: 10⁹ Hz, the "speed" of new computers exceeds a GHz

GIGO: garbage in, garbage out

global warming: we are the cause, and we will pay the price

gradian (grad): angle measure, 100 of them in 90^o

gradient (another grad): change of something per distance

gram: unit of mass; the mass of 1 cm³ (1 ml) of water

*grating: dsinq = ml is equation for a maximum, m=0,1,2,…

*gravitation: You are attracted to your physics book.

Gravitation is just a theory, not fact, so keep an open mind about it.

*gravitational potential energy: mgy (y small compared to R of Earth) or -GMm/r

*gravity: force = mg = GMm/r² , G = 6.6726 x 10^-11 Nm²/kg²

gray (Gy): unit for absorbed radiation per mass; 1 Gy = 1 J/kg. Rad = 0.01 Gy.

greenhouse effect: why a car in sunlight gets warm inside

greenhouse gases: CO₂, CH_4,  etc. cause global warming

*ground: how electric power companies use it

ground-fault interrupter (GFI) turns off electric power if hotwire current is not = neutral wire current

ground state: lowest energy state

growth, hair: several nm/s, so if you were atom sized, it would look like a train coming out of a tunnel

GUI = graphic user interface, dialog boxes, menus...

Gunn diode has negative dV/dI over a small range, useful for radar gun oscillators

 h = Planck's constant, 6.626 x 10^-34 Joule second

h = height or depth

H = Hubble constant, 2.3 x 10^-18 s^-1  H x distance to galaxy = its speed

h-bar = h/2p, written with a bar through the upper stem of the h

hc = 1240 electron volt-nanometer

hadron: heavy particles that contain quarks; mesons have 2 quarks, baryons have 3

half life: time it takes for half to decay

hand = 4 inches (unit used in measuring horse height)

healing touch: placebo effect at its finest hour

*heat energy Q: D Q means heat energy added to a body

*heat engine: highest, lowest temps T_H and T_L, e < 1-T_L/T_H (never = in reality)

Heisenberg uncertainty principle, D pD x > h? I'm not sure. Also D ED t > h?

helium was discovered on the Sun before on Earth (helio = prefix meaning sun)

Helmholtz resonator: when you whistle, your mouth is one

Hertz: a car rental company

*hertz (Hz): a cycle per second

Higgs boson: undiscovered particle, thought to give other particles mass

hire education: today's higher education

holes in semiconductors (electron vacancies) act like positive charges

horsepower: 746 W or 550 ft-lb/s. You do a hp running up stairs? Almost.

Hubble constant: H = 1/age of universe = 2.3 x 10^-18 s^-1 .  (speed = H times dist.)

Huygens' principle: Each point in a wave front is a source of semi-spherical waves.

hydrogen atom: E_n = -13.6 eV/n² = energy of electron, n = 1,2,3,… normal is n=1

hydrogen economy: when we convert to solar, use hydrogen for fueling cars, etc

 I or i: symbol for electric current, = charge/time; also I = inertia in mechanics

i: unit vector in x direction

image: in optics, the image looks like a replica of an object (but could be larger or smaller)

image, real: would show on a screen if a screen is placed there

image, virtual: looks real, but would not show up on a screen. Look at a plane mirror.

impedance of a series RCL circuit: Z=(R²+[X_L-X_C]²)^1/2 see ind. & cap. reactance

*inclined plane problems if you are so inclined

incoherent light: all but laser. Phase at one location is not related to phase elsewhere.

incompetence: what we strive to achieve- keep getting promoted until you have it

index of refraction: speed of light in vacuum/speed of light in a medium

*inductance: L = S f /i or Nf _av/i where N=loops in coil, current i causes flux f

inductive reactance: X_L = w L, opposition to AC in Ohms; w in rad/s, L in henrys

inductive time constant = L/R, so 1 minute is 60 henry/ohm

inertia: difficulty to change the motion of a body. Mass is a measure of inertia for non-rotationals.

inertia, rotational, or moment of inertia, I = ò r²dm, used in S t =Ia

inertia of Earth: I = 8.021 x 10³⁷ kg m²

inertial reference frame has zero acceleration. Earth reference frame: not quite inertial, but close.

inflationary universe: about 10^-35 s after the big bang, brief rapid expansion

insulators or dielectrics: electrons are stuck to the atoms

intaxication: euphoria due to tax refund

integral of d(cabin)/cabin = natural log cabin

intelligent design is neither: total nonsense; see Elvis sightings

intensity of light: the average Poynting vector, ExB/m_o

interference of waves: they add; see phasors for a way of adding

inverse square law and its abuse

ion: charged atom. Two atoms walking together. "Oops, lost an electron." "Are U sure?" "I'm positive."

irreversible process in thermodynamics: cannot reverse it by making small changes

iso prefix means constant, isochoric = isovolumetric, isothermal = const. temp

isotope: same atomic number, hence same chemical properties, but different mass.

 j: unit vector in y direction

Jar file: Java archive file

jet engine thrust: see rocket thrust, but include a negative term for the intake

*joule (J), energy unit, a newton× meter (N× m), also = watt×second (W×s)

 K: kelvin, a unit of temperature; ^oC+273; see kelvin

k: Boltzmann's constant, gas law constant R divided by Avogadro's number

k: spring constant; spring force = -kx, where x = stretch distance

k: unit vector in z direction

*kelvin temperature scale: based on Celsius, but zero is really zero

Kepler's laws (planets): elliptical orbits, equal areas in equal time, T² µ a³

kilogram (kg): SI mass unit. It weighs about 2.2 lb on Earth.

kilowatt hour: energy = 3.6x10⁶ J; E in kwh = power in kW x time in hours

*kinematics: distance, velocity, acceleration and time relationships; see linear motion

kinetic friction: sliding friction, f = mN, where m  is coefficient of kinetic fric, N=normal f.

*kinetic energy: ¹/₂mv² ; if v is near the speed limit c, KE = (g -1)mc² ; see gamma

*kinetic theory of gases : pressure law found by Newton's laws

Kirchhoff's rules: current toward junction = current away; sum of  DV around loop = 0

 L: latent heat, angular momentum, inductance

laser: light amplification by stimulated emission of radiation. Emits coherent light.

latent heat of fusion, vaporization, L_f, L_v: heat required per mass for melting, boiling

law = old theory. Gas “laws” are approximations “Theory” of relativity seems exact. (Another usage is that a law is a specific relationship and a theory is a collection of related laws.)

law of cosines is Pythagorean theorem with an extra term when the angle ¹ 90^o

*laws of motion: Newton's 1st, 2nd, 3rd SF=ma and action-reaction forces

LC oscillations (coil and capacitor): w = (LC)^-1/2

leap second: in most years they put an extra second in the last minute

LED: light emitting diode

*lenses and mirrors: one equation fits all

lepton =  light mass particle;  hadron = heavy particle

lepton: lightweights electron, muon and tau and the 3 corresponding neutrinos

lever: bar that pivots at point called the fulcrum

light: derive the wave equation from electricity and magnetism

light emitting diode (LED): a diode that emits (guess what)

light speed: about 3 x 10⁸ m/s

light-year: unit of distance, the distance light travels in a year, 9.46 x 10¹⁵ m

*linear motion (straight line motion with constant acceleration)

liquid: molecules packed close together, but are not stuck in position. In a solid they are locked in place.

logarithm of x is the power that the base needs to be raised to get x

logarithm of base 10: log(1000) = 3, because 10³ = 1000

logarithm of base e: natural log or ln.  ln(e²) = 2

*loop equation (Kirchhoff 's): S D V around circuit loop = 0

Lorentz factor g = (1-v²/c²)^-1/2 (see relativity, special)

lottery: a tax on people who are bad at math

love wave: transverse surface earthquake wave with vibration parallel to the surface

luck: the harder you work, the more you get

lucky: if you feel lucky your chances are the same

lumen: 1/680 watt at 555 nm (peak eye sensitivity); other colors need higher power

lumens/watt: incandescent bulb, 15. fluorescent, 50. firefly, 650. Ideal = 680

luminous intensity: 1 candela = 1 lumen/sr (sr = steradian, solid angle)

luminous intensity, an odd name for it; usually intensity is something per area

lunar gravity: g_moon = 1.62 m/s² at moon's surface

lux: lumen/m²

 m: symbol for mass; abbreviation of meter, milli-

M: mega- (million); (but M = 1000 as a Roman numeral)

magnetic dipole: north & south pair of magnetic poles, equal in strength

*magnetic field B: moving charge q has force on it, F=qvxB

magnetic flux: B times perpendicular area, tesla×meter²

magnetic flux quantum: h/(2e) = 2.068 x 10^-15 T×m²

magnetic force of attraction between magnets

magnetic monopole: it would be nice if it existed

magnetic monopole derivation of the Biot-Savart law

magnetic Pole: someone from Poland with a nice personality

magnetic N and S poles of a magnet do not exist in isolation

*magnetism

magnets for healing: total nonsense; see Elvis sightings

magnets for improved gas mileage: total nonsense; see Elvis sightings

magnets for relieving pain: total nonsense; see Elvis sightings

magnets for water purification: total nonsense; see Elvis sightings

magnets for $: that explains the above four

*mass: toe-stubbing property of matter; kick a brick in outer space and you will see

mass defined: apply same force to different objects, then m₁a₁=m₂a₂…

mass measured: use a balance

mass-energy equivalence:  E = mc² , E and m are two forms of the same thing

mass of: Earth, 5.975 x 10²⁶ kg, Moon, 7.35 x 10²² kg, Sun, 1.987 x 10³⁰ kg

mass of: electron, 9.1094x10^-31 kg, proton, 1.6726x10^-27 kg, neutron, 1.6749x10^-27

masses in E/c² units: elec 0.511 MeV/c² , proton 938 MeV/c² , neutron 939 MeV/c²

mean life: Al Capone's for example. In radioactivity it is half-life/ln2

*mechanics main page: stuff you need to know first

mega (M): one million, 10⁶

megahertz: a million hertz, each trying to rent you a car (see Hertz)

meltdown: nuclear reactor disaster, Chernobyl reactor had a meltdown.

MEMS: micro electro-mechanical system

meson: quark-antiquark pair

Metabolism rate/mass: you, ~2 W/kg.  Sun, ~2x10^-4 W/kg

meter: SI unit of length. 1 inch = 2.54 cm = 0.0254 m

micro (m): 10^-6

Microsoft: 10^-6 soft

milli (m): 10^-3

molecule: two or more atoms bonded together

moment of inertia: I = mass times square of distance from axis, I = ò r²dm

*momentum = mv; collision problems, etc.; conserved if S F =0 on system

Moon is receding 3.8 cm/y due to gaining energy from Earth tides.

Moore’s law: computer speed doubles every 1.5 year or so; cannot last.

mu (m) micro, 10^-6

muon, tau & electron: leptons (each has a corresponding neutrino, also leptons

Murphy's laws apply to all of this stuff, to tell you the truth

 n: symbol for index of refraction in optics; principal quantum number in atom physics, nano

*N: symbol for newton, the SI unit of force; sometimes N= normal force

nano (n): 10^-9

n-type semiconductor has free electrons due to being doped with valence 5 element

neutrino has very tiny mass; oscillates between types

neutron is a dud (up quark and two downs, see quark); can pair up into 2(dud)

*newton = unit of force, approximately 0.225 lb, named after a fig-filled cookie

*Newton's law of gravitation and how Sir Isaac found it

Newton's laws: even the worst criminals obey them:   F_net = ma, action-reaction: F & -F

*Newton's laws of motion finally put Aristotle's mistaken views to rest

*newton-meter = joule (J), energy unit; J = watt× second (W× s)

NIMBY: not in my back yard

*node: stationary point in a standing wave

*normal force is ^ to a surface; if m is on a surface tilted q from horiz, N is mgcosq

north pole of a magnet is north-seeking pole; hung by a thread, it points north.

nuclear fission: splitting large nuclei gives off energy- the fragments repel each other A LOT.

nuclear fusion: (in stars, H bomb) Nuclei merged, energy given off if they are small nuclei

nuclear power: fission. radioactive waste problem, but no greenhouse gases

nucleon: proton or neutron, each containing 3 quarks

nucleus of atom = manic-depressive :) swarm of up and down quarks (see quark)

nucular: Dubya's pronunciation of nuclear

 obfuscation:  like a pride of lions, an obfuscation of administrators

objective lens: the lens on telescope or microscope nearest the object viewed

*ohm, abbreviated W : unit of resistance defined by Ohm's law

ohm× farad (W × f): time of 1 second, as in "I'll be ready in a few ohm× farads"

*Ohm's law: V = IR, voltage across resistance R carrying current I

one size gives fits to all

optical fibers depend on total internal reflection

optical computers: someday…

*optics: when you read this, you are using optics, your eyes' lenses focus on retina

*orbit of a satellite, circular or elliptical

overtones: usually multiples of the fundamental frequency (musical instruments)

 p is symbol for momentum; p = mv  or

p = object distance in optics

P = pressure = force/area

p-type semiconductor has free holes due to being doped with valence 3 element

pair production: a photon disappears and a particle-antiparticle pair is born

parabolic mirror concentrates sunlight at its focus

parabolic path of *projectile

parallax: apparent motion of something caused by motion of the observer

parallel axis theorem: I = I_cm+mh² (=inertia; h is distance from axis to center of mass)

paramagnetism: weak attraction to magnet, an electron spin effect, see diamagnetism

parsec (pc): 3.26 light years or 206,000 astronomical units

*pascal (Pa): SI unit of pressure, N/m²; see absolute P, gauge P, and pressure

Pauli principle: no two electrons in an atom can have the same state

pendulum: w = (g/L)^1/2

penumbra: partial shadow next to umbra, the full shadow

perigee:  (Greek ge = earth) low point in orbit about Earth (apogee is high pt)

perihelion: (Helios = Greek God of Sun) low point in orbit about Sun

period T: time of a complete cycle or 2p radians; T=1/f where f = frequency in Hz

permanent magnet motors got a boost when they found magnets that can take high temp

permeability constant m _o = 4p x 10^-7 T× m/A for empty space

permittivity constant e _o = 8.85418781762 x 10^-12 F/m for empty space

perturbation: small deviation from normal

petroleum: will become too expensive for routine use in about 20 to 50 years

phasors: rotating vectors, useful in AC and in theory of gratings

photocopier: selenium becomes a conductor when illuminated

photon: minimum energy pulse of light, energy = hf, Planck's const. times frequency

photon momentum = h/l

photonics: light + electronics

photovoltaic cells or solar cells: they will replace fossil fuels

physical pendulum: any pendulum, really; w = (mgh/ I)^1/2, h distance from pivot to CM

physics: everything real

pi (p ): half a pie, a 180^o portion (p radians = 180^o)

pie: 2p (full circle is angle 360^o or 2p radians)

pico (p): 10^-12

piezoelectricity: squeeze a crystal and a voltage is produced

PIN diode: has intrinsic (undoped) layer between P and N layers

pion: unstable because it's made of only two quarks

pitch (sound): frequency. If mixed frequencies, the ear judges it.

plagiarism: copying the work of one person; see research

Planck's constant h = 6.62606876 x 10^-34 J× s

Planck length L_P = [hG/(2p c³)]^1/2 = 1.62 x 10^-35 m (some think it might be important)

Planck mass M_P = [hc/(2p G)]^1/2 = 2.18 x 10^-8 kg (this is huge compared to atom masses)

Planck time T_P = [hG/(2p c⁵)]^1/2 = 5.39 x 10^-44 s (note that c = L_P/T_P)

*plane wave of light: E = E_msin(kx - w t) goes toward +x, speed =
c=w /k =(e _o m _o)^-1/2

plasma: gas of charged particles

PM motor: permanent magnet motor. Can be used as generator.

p-n junction: millions of them are serving you right now in your computer

polarized light: E field in a plane (and B field ^)

pole of magnet: N named because it points north (hence Earth has S near the North Pole)

*potential energy: stored energy

*power: rate of doing work; SI unit is watt (W) = J/s (see work, energy, joule)

power, typical person's daily average ~100 W, or ~2 W/kg.  Sun, ~2x10^-4 W/kg

Poynting vector: S = ExB/m _o = power/area in light wave, intensity vector

precession: conical motion of axis of spinning top, gyroscope, Earth, etc.

precession of Earth's axis has a period of about 26,000 years

*pressure: ^ force on surface divided by the area; see absolute P, gauge P, pascal

pressure vs depth h in a fluid: P=P_o+rgh

primary colors: red green blue; get a powerful magnifier and look at your screen

primary colors in art are the complements of the above; pigments subtract light

*prism: usually triangular chunk of glass

*projectile motion: v_x = constant and v_y changes at the rate of g, the free fall rate

projectile, initial angle to maximize x: tanq = v_o/v_f

proper length D L_o = length as measured by instrument at rest with respect to the thing

proper time D t_o : time interval between two events measured by clock located there

proton: two up quarks and a down, see quark

psycho-kinesis: total nonsense; see Elvis sightings. All who believe it, please raise my hand.

psychic mind readers: total nonsense; see Elvis sightings

psychic predictions of future events: total nonsense; see Elvis sightings

psychro- prefix meaning cold

psychrometer: measures humidity by evaporative cooling

Ptolemy theory: Earth centered theory, a reasonable idea at the time

pyramid power: total nonsense; see Elvis sightings

*Pythagorean theorem: h² = a² + b², h=hypotenuse of right triangle, a&b=other 2 sides

*q: symbol for charge or for heat energy

quanta: plural of quantum

quantized: something that comes in steps, not a continuous change, is said to be quantized.

quantum: smallest unit. quantum of light is photon, q of charge is electron or quark

quantum computers: some day…

quantum mechanics of a crap game showing some of the lingo

quantum phenomena: discontinuous steps with no in-between

quantum theory: waves are particles and particles are waves

quantum vectors: a little on the symbolism and a few operations

quark: in normal matter, two types named up and down, charges ²/₃e and -^1/₃e

quarks in protons, neutrons: udu, dud.

quark masses: u, 4 MeV/c²; d, 7 MeV/c² ; see Mega, eV, c, E = mc²

R: radius; resistance; resolving power; gas law constant R=8.31 Joule/(mole× Kelvin)

rad: radiation dose, 0.01 Joule of radiation energy per kg of material, see rem, see gray

rad: abbreviation of radian, see below

radian: dimensionless angle measure, arc length divided by radius; 1 rad=180^o/p

radiation, thermal: esT⁴ is the power/area; emissivity Stefan-Boltzmann const. temp⁴

radio waves: electromagnetic, like light. speed = c = 3.00 x 10⁸ m/s

radioactive dating: if she is radioactive, don't date her

radiocarbon dating: ¹⁴C is produced in atmosphere, half life 5730 years; plants get it

radon: a radioactive gas; can seep into your basement

Rankine temperature scale (an absolute scale): add 460 to Fahrenheit temperature

ratio of specific heats: C_p/C_v = 5/3 for monatomic, 7/5 for diatomic gas

ray diagrams work for mirrors and thin lenses

RC circuit: V = V_¥ +(V_o-V_¥ )e^-t/RC , & many things follow same equation

reactance: two types, capacitive and inductive, X_C and X_L in Ohms

*real image: the light is really there (as opposed to virtual image); go optics

reasoning, circular: see circular reasoning

red: longest wavelength light your eye can detect

red giant: when our Sun becomes one (in a few billion years), Earth will be vaporized

reflection: light bounces off, sort of; equal angles from mirror

refraction: bending of light entering a material (unless light is ^ to surface) see Snell

*relative velocity: all velocities. If unstated, it is usually v relative to Earth

relative v example: You are going 50 mph; a 60 mph car passing you has v=10 mph relative to you.

relative v example 2: This time the 60 mph is going the opposite direction. Then v=110 mph rel. to you.

relativity: special (constant v) and general (accelerated frames and gravitation)

rem: rad adjusted for mammals. 1 rad a 's = 10 to 20 rem; for others rad » rem

research: copying the works of many people; see plagiarism

*resistance R: series, R_s = S R; parallel R_p=1/S (1/R); R_p= product/sum for two.

resistivity r : inverse of conductivity; R=r L/A is R of uniform wire or....

resonance: frequency match up causes high amplitude

*resultant = vector sum

Richter scale for earthquakes is like the bel scale for sound (but we use decibels)

*right-hand rule for rotations: r.h. fingers curl in rotation direction, thumb=vector

*rh rule for magnetic field of current: thumb in I direction, fingers in B direction

rms: root-mean-square, the square root of the average of the squares

rms voltage of sinusoidal AC: V_rms=V_peak/2^1/2

robots: big future- farming, manufacturing, exploring, rescuing, ....

rocket thrust: force is relative velocity of the exhaust times the mass rate, dm/dt

Roentgen: 1 R produces ions of charge 2.58x10^-4 C in 1 kg of dry air at STP

*rotational acceleration a = rate of change of spin w; a =dw /dt

rotational inertia I = mass times square of distance to axis of rotation; I =ò r²dm

rotational speed or velocity w can be considered vector

 s: second

S: entropy; here we deal only with D S, heat added divided by absolute temp.

sanity: a productive form of madness (from Santayana, I think)

*satellite orbits: circular or elliptical; the physics behind Kepler's empirical laws

Saturn's rings: dust, rock and ice in orbit

Savonius wind machine: vertical axis with two half-cylinder blades:  ⁽ ₎

*scalar: a non-vector quantity such as time, mass, work, energy, temperature…

*scalar product: non-vector multiplication of vectors, aka dot product of 2 vectors

*scalar product of 2 vectors= maximum + if vectors are parallel, - if antiparallel

scaling: effect of size. An elephant-size mouse's leg bones would break.

Schrodinger's equation is to quantum mechanics as Newton's laws is to classical mech.

Schwarzchild radius: 2GM/c² , something with smaller radius is a black hole.

scientific method: any reasonable method that would convince a skeptic

scientific notation: (number between 1 and 10) x 10^{whole number} , 6.02x10²³ for example

SCR: silicon controlled rectifier

seasons: N hemisphere farther from sun in summer! Angle of sunlight is the key

second law of thermodynamics: total entropy cannot decrease

second law, another version: heat energy cannot flow by conduction to the warmer body

self inductance (or inductance): L in henrys as in e = -Ldi/dt

semiconductors: diamond, germanium and silicon, for example

semiconductor physics & lasers: try http://www.britneyspears.ac/lasers.htm (good phys, no joke)

*series and parallel circuits and beyond s&p

SETI: search for extraterrestrial intelligence

shock wave: sonic boom for example, when plane travels faster than sound

SI units: kilogram, meter, second, Ampere, Kelvin, mole, candela are the base units

sidereal: measured with respect to distant star, not the Sun

*simple harmonic motion (SHM): x = Asinwt  when force toward center prop. dist.

*sine of q (sinq ) = side opposite/hypotenuse in a right triangle

*single slit of width a: light thru it has minima where asinq  = ml    m=1,2,3,...

siphon, more than you wanted to know about it

slug: unit of mass in British system (for S F=ma); 1 slug weighs 32 lb

slug: snail-like critter without shell; weighs about 0.0032 lb and is delicious

*Snell's law shows how light bends when it goes from one material to another

soh cah toa: sine=opp/hyp, cosine=adj/hyp, tangent=opp/adj

solar cells: price dropping, fossil energy prices rising; eventually solar will be king

solar constant: power/area of sunlight just above atmosphere, 1.37 kW/m²

solar energy is the energy of the future; fossil fuels will be too expensive

solution: if you are not part of the solution, you are part of the precipitate

sonic boom: shock wave from something going faster than sound

*sound waves and the theory behind it

*sound waves in air, velocity is a function of temperature

*sound waves, standing, inside horns and woodwinds, for example

space exploration: use robotics, stupid

space: particle-antiparticle pairs pop into existence, then disappear

*specific heat capacity C in the equation D Q = CmD T

spectrometer, spectroscope: separates light into its component wavelengths

spectrum: rainbow is an example

*speed and velocity: velocity is a vector, speed is magnitude of v.

speed limit in nature is the speed of light- that seems like nonsense but it is true

speed of dark = speed of light

speed of light, c: see c, si? (sigh) 29,979,458 m/s » 3.00 x 10⁸ m/s

speed of molecules in a gas: average kinetic energy of one is ³/₂kT

speed of sound in air, a function of temperature

spider hole: Saddam was found in an Iraqnid hole

spin up and spin down (viewed from above, clockwise is down)

*spring: f = -kx and PE = ¹/₂kx² for linear spring such as a coil spring

*spring constant: the k in the above equations, force per stretch distance

*standing waves: sum of two running waves moving in opposite directions

*standing waves: node to node distance is l /2

*standing waves on a string: plunk a guitar

*standing waves, sound: toot a flute

states of matter: solid, liquid, gas, liquid crystal, supercooled liquid, superfluid, plasma,
states of matter, continued: Bose-Einstein condensate, neutron star, black hole,…

*static friction: we would not exist without it

statics: S F = 0 and S t = 0 ® zero acceleration, zero angular acceleration

Stefan-Boltzmann constant s = 5.67x10^-8 W× m^-2× K^-4 (see blackbody radiation)

steradian: unit of solid angle, area as "seen" by a point divided by distance squared

strong force: one of two nuclear forces, the other is the weak force

Sun: 1.50x10¹¹ m from Earth, "metabolic" rate = 2x10^-4W/kg, about 1/5000 of yours

Sun's energy source: very slow fusion of hydrogen into helium, see above

superconductivity: resistance exactly zero caused by a quantum effect

supercool: cool a liquid and it can dip below its freezing point before freezing

supernova: star blow-up; those C, O and N atoms in your body came from supernovas

*superposition of waves: fancy term for addition of waves

superstring theory: elementary particles are strings? maybe….

surface tension: water molecules attract each other, so surface layer is more dense

sustainability: capable of continuing forever, unlike modern agriculture etc. in US.

 t: time

T: absolute temperature; period of an oscillator (time of one cycle)

*tangent of q (tanq ) = side opposite/side adjacent in a right triangle

tangent to a circle: straight line touching circle at one point, perpendicular to the radius

tau, muon & electron and their corresponding neutrinos are the lightweights: leptons

telescope and microscope formula for building the simplest lens types

*temperature: absolute T is proportional to average kinetic energy of a molecule

Tera:  THz = 10¹² Hz, for example

terminal velocity: v when falling body has air drag = weight

*Tesla, SI unit of magnetic flux density B (some people object to calling B mag. field)

theory usually means a well-verified collection of laws and principles about an aspect of nature

thermal refers to heat. thermal conduction, thermal energy....

thermionic emission: heating a filament causes electrons to "boil" off

thermistor: semiconductor; it drops in resistance with rise of temperature

thermocouple: electricity from heat with no moving parts, but very inefficient

*thermodynamics: work output from heat energy

thermodynamics, laws of: You 1) can't win. 2) can't break even. 3) must play the game.

thermodynamics: 1) conservation of energy   2) heat conduction toward cooler, or total entropy cannot decrease

thermopile: a bunch of thermocouples

Thevenin's theorem: replace a complex network of resistors and batteries with 1 battery and 1 resistor

thick lenses: don't click on it, it won't tell anything about them

*thin lenses click it. one equation fits all mirrors and thin lenses if you get signs right

thyristor: SCR, triac: transistor-like components for dimmers and other controls

tides transfer energy from Earth to Moon, causing Moon to move farther away

time: that which I don't have enough of (besides brains) to explain much about

time constants: for capacitors, RC and for inductors, L/R.

time dilation: time slows down as v approaches c.  t = g t_o  (see gamma)

ton = 2000 pounds

tonne (metric ton) = 1000 kg = 2200 lb

ton of TNT has energy 4.1 GJ

*torque t = rxF twists things; S t = Ia, see inertia I, ang. accel. a and vector prod.

torr: unit of pressure = 1 mm of mercury measured by a mercury barometer

Torricelli's theorem: Water squirting out hole in open tank at depth h has v = (2gh)^1/2

torsion pendulum, twisting back and forth

total internal reflection: if your calculator says ERROR when you calculate refraction

*transformer: changes the voltage of AC; voltage ratio = turns ratio

transistor: current regulator made of semiconductors; like a faucet controls water flow

*transverse waves: vibrations ^ to the wave velocity

*trigonometry: see sine, cosine and tangent, then memorize those definitions

triple point, water (3 phases in equilibrium): 0.01 ^oC and P = 4.62 torr.

Tropic of Cancer, Capricorn: Sun is straight above 6/20+, 12/20+ (23.5^o N, S latitude)

tunneling: electron or other particle disappears and reappears elsewhere!

turbulence: in flowing fluid, random swirls

 ultrasound: frequency too high for the ear-brain system to detect

ultrasound: defined as f >20 kHz, but you probably can't hear 15 kHz

ultraviolet light: frequency too high for the eye-brain system to detect

uncertainty principle: I dunno, maybe check out Heisenberg

unified field theory: maybe in 20 years we will have one super theory of everything

*uniform circular motion: constant a , so easy equations apply

*units: conversions, and you should know the SI electrical units

unit vectors: i, j, k magnitude = one; direction in x,y,z directions, respectively

universal gravitational constant G = 6.6726 x 10^-11 N× m²/kg²

universe: as far as we know there is only one, but we cannot know for certain

up (quark, u): rest energy 360 MeV, charge ²/₃ e; proton is uud

uranium 235 is fissionable, 238 is not, but 238 can be converted to plutonium

 vacuum: no perfect one is possible (but we cannot be absolutely certain of anything)

vacuum polarization: particle-antiparticle pairs pop in and out of existence

van de Graaff generator: carry charge on a belt to the inside of hollow sphere

*vaporization: heat energy required = L_vm (L_v = constant, latent heat of vaporization)

*vector addition: usually add corresponding components, but there are other ways

vector product or cross product: AxB is ^ to the AB plane

*vectors: in mechanics and in quantum mechanics

*velocity: average v = distance traveled/time, instantaneous v = dx/dt (d = small D )

*vibrations: we deal only with the simple harmonic motion type here

*virtual focus: parallel light thru concave lens diverges; trace it back to a point

*virtual image: at its location the light is not really there; see real image

viscosity h : resistance to flow of a fluid is proportional to h

visible light wavelengths = about 400 to 700 nm, due to eye, not property of light

*volt: unit of electrical potential energy per charge. 1 V = 1 J/C

*voltage acts like electrical pressure; I = D V/R, like vol flow rate below

volume flow rate dQ/dt = D P/R, pressure difference divided by resistance

volumes: Ah if constant area A such as cylinder, pr²h. Others: sphere, (4/3)pr³

volume, contin. pyramid and cone, (1/3)Ah 

volume, contin. torus (donut), area of circular part times circumference of center-line

 W: watt

waist: a terrible thing to mind

waste: a terrible thing, mind you

*watt (W): SI unit of power, watt = joule/second (W = J/s); James Watt, James Joule

wave equations: plane wave and a differential equation for strings, sound, light

*wavelength l : distance between identical parts of wave; crest to crest, for example

*waves, longitudinal: on a spring and sound- vibrations parallel to wave v

*waves, main page

waves, transverse: on a string and light waves derived using a differential equation

*wave velocity v = f l , frequency times wavelength

weber: magnetic flux unit in SI (flux is BA _^ ) weber = tesla meter²

weak force: one of two nuclear forces, see electroweak

*weight: w= force of gravity mg; some define it as a scale reading, the normal force

weightless: in free fall ref. frame, it is as if gravity doesn't exist. See general relativity

white light: mixture of all colors; white people are colored people

white on your computer screen = red, green and blue dots (get a powerful magnifier)

WiFi: wireless fidelity

wind power: ¹/₂ r Av³ , 0.59 (= Betz coefficient) of this is max possible to capture

wind power output of wind machine » 0.2r Av³ (r density, A area, v speed of wind)

*work: component of force in direction of motion times distance moved

*work and energy: work is energy transfer; SI unit is N× m=joule

*work done by expanding gas is average pressure times change of volume

*work-energy theorem: total work by all forces = change of kinetic energy

world problems we can't solve: global warming, overpopulation, fossil fuel depletion

WYSIWYG: what you see is what you get

 x,y,z unit vectors i, j, k

 x component of acceleration of a projectile: zero (if no air drag)

x component of velocity of a projectile: constant (if no air drag)

x direction unit vector i = magnitude 1 in x direction

xor gate: exclusive or gate. 1&1--> 0. (In a regular or gate, 1&1--> 1)

x-ray: f > ultraviolet frequency; fuzzy border between them around 10¹⁷ Hz

x-ray diffraction is something to Bragg about

y component of acceleration of a projectile: g straight down

y component of velocity of a projectile: changes as in free fall

y direction unit vector = j, dimensionless, magnitude = 1

yocto- (y): 10^-24

Yotta- (Y): 10²⁴

You are exchanging virtual gravitons with planet Earth.

You are unique, just like everyone else.

You will obey Newton's laws.

Young's elastic modulus E: F/A = -ED L/L ; see also bulk modulus B

*Young's experiment: the double slit experiment with light

z axis unit vector: k, dimensionless, with magnitude = 1

zed = zero in British-English-speak; sum of all forces in the universe = zed

zepto- (z) = 10^-21

zero, absolute: -273.15 ^oC

zero electric field inside a conductor with no current

zero^th law of thermodynamics: equilibrium temperature reached…

zetta- (Z) = 10²¹

Main pages:
forces and motion
fluids, heat, electricity and magnetism
vibrations and waves
quantum

e-mail me your ideas at fredrick.gram @ tri-c.edu  (remove spaces)