In this glossary, key symbols and notation are briefly defined.
| Symbol | Definition |
|---|---|
| \(\overline{\text{any symbol}}\) | average (indicated by a bar over a symbol—e.g., \(\overline{v}\) is average velocity) |
| \(°\text{C}\) | Celsius degree |
| \(°\text{F}\) | Fahrenheit degree |
| \(\text{//}\) | parallel |
| \(\perp\) | perpendicular |
| \(\propto\) | proportional to |
| \(\pm\) | plus or minus |
| \({}_{0}\) | zero as a subscript denotes an initial value |
| \(\alpha\) | alpha rays |
| \(\alpha\) | angular acceleration |
| \(\alpha\) | temperature coefficient(s) of resistivity |
| \(\beta\) | beta rays |
| \(\beta\) | sound level |
| \(\beta\) | volume coefficient of expansion |
| \(\gamma\) | gamma rays |
| \(\Delta\) | change in whatever quantity follows |
| \(\delta\) | uncertainty in whatever quantity follows |
| \(\Delta E\) | uncertainty in energy |
| \(\Delta m\) | difference in mass between initial and final products |
| \(\Delta N\) | number of decays that occur |
| \(\Delta p\) | change in momentum |
| \(\Delta p\) | uncertainty in momentum |
| \(\Delta \PE_{\text{g}}\) | change in gravitational potential energy |
| \(\Delta \theta\) | rotation angle |
| \(\Delta s\) | distance traveled along a circular path |
| \(\Delta t\) | uncertainty in time |
| \(\Delta V\) | potential difference |
| \(\Delta x\) | uncertainty in position |
| \(\epsilon_{0}\) | permittivity of free space |
| \(\eta\) | viscosity |
| \(\theta\) | angle between the force vector and the displacement vector |
| \(\theta\) | angle between two lines |
| \(\theta\) | direction of the resultant |
| \(\lambda\) | wavelength |
| \(\theta_{lambda}\) | wavelength in a medium |
| \(\mu_{0}\) | permeability of free space |
| \(\mu_{\text{k}}\) | coefficient of kinetic friction |
| \(\mu_{\s}\) | coefficient of static friction |
| \(v_{e}\) | electron neutrino |
| \(\rho\) | density |
| \(\rho_{\text{fl}}\) | fluid density |
| \(\overline{\rho}_\text{obj}\) | average density of an object |
| \(\rho/{\rho }_{\text{w}}\) | specific gravity |
| \(\tau\) | torque |
| \(\varphi\) | phase angle |
| \(\Omega\) | ohm (unit) |
| \(\omega\) | angular velocity |
| \(A\) | ampere (current unit) |
| \(A\) | area |
| \(A\) | cross-sectional area |
| \(A\) | total number of nucleons |
| \(a\) | acceleration |
| \(a_{\text{c}}\) | centripetal acceleration |
| \(a_{\text{t}}\) | tangential acceleration |
| \(\text{AC}\) | alternating current |
| \(\text{AM}\) | amplitude modulation |
| \(\text{atm}\) | atmosphere |
| \(B\) | bulk modulus |
| \(B\) | magnetic field strength |
| \(\text{Bq}\) | becquerel—one decay per second |
| \(C\) | coulomb (a fundamental SI unit of charge) |
| \(\text{CG}\) | center of gravity |
| \(\text{CM}\) | center of mass |
| \(c\) | speed of light |
| \(\text{Cal}\) | kilocalorie |
| \(\text{cal}\) | calorie |
| \(\cos{\theta}\) | cosine |
| \(\cot{\theta}\) | cotangent |
| \(\csc{\theta}\) | cosecant |
| \(D\) | diffusion constant |
| \(d\) | displacement |
| \(\text{dB}\) | decibel |
| \(\text{DC}\) | direct current |
| \(E\) | total energy |
| \(\text{Eff}\) | efficiency—the useful work output divided by the energy input |
| \(E_{\text{in}}\) | energy consumed (food digested in humans) |
| \(E_{\text{out}}\) | energy output |
| \(e\) | emissivity of an object |
| \(\text{eV}\) | electron volt |
| \(\vb{F}\) | force |
| \(F\) | magnitude of a force |
| \(F\) | restoring force |
| \(F_{\text{B}}\) | buoyant force |
| \(F_{\text{c}}\) | centripetal force |
| \(F_{\text{i}}\) | force input |
| \(\vb{F}_{\text{net}}\) | net force |
| \(F_{\text{o}}\) | force output |
| \(\text{FM}\) | frequency modulation |
| \(f\) | frequency |
| \(f_{\text{k}}\) | magnitude of kinetic friction |
| \(f_{\s}\) | magnitude of static friction |
| \(G\) | gravitational constant |
| \(g\) | acceleration due to gravity |
| \(h\) | change in vertical position |
| \(h\) | height above some reference point |
| \(h\) | maximum height of a projectile |
| \(h\) | Planck's constant |
| \(\text{hf}\) | photon energy |
| \(I\) | intensity |
| \(I\) | moment of inertia (also called rotational inertia) |
| \(I_{\text{rms}}\) | average current |
| \(\J\) | joule |
| \(\text{K}\) | kelvin |
| \(k\) | Boltzmann constant |
| \(k\) | force constant of a spring |
| \(\text{kcal}\) | kilocalorie |
| \(\KE\) | translational kinetic energy |
| \(\KE+\PE\) | mechanical energy |
| \(\KE_{e}\) | kinetic energy of an ejected electron |
| \(\KE_{\text{rel}}\) | relativistic kinetic energy |
| \(\KE_{\text{rot}}\) | rotational kinetic energy |
| \(\overline\KE\) | thermal energy |
| \(\kg\) | kilogram (a fundamental SI unit of mass) |
| \(L\) | angular momentum |
| \(\text{L}\) | liter |
| \(L\) | magnitude of angular momentum |
| \(m\) | magnification |
| \(m\) | mass |
| \(\m\) | meter (a fundamental SI unit of length) |
| \(m\left({\text{}}^{A}\text{X}\right)\) | atomic mass of a nuclide |
| \(\text{MA}\) | mechanical advantage |
| \(m_{e}\) | mass of the electron |
| \(m_{n}\) | mass of a neutron |
| \(\text{mol}\) | mole |
| \(m_{p}\) | mass of a proton |
| \(N\) | magnitude of the normal force |
| \(\N\) | newton |
| \(\vb{N}\) | normal force |
| \(N\) | number of neutrons |
| \(n\) | index of refraction |
| \(n\) | number of free charges per unit volume |
| \(N_{\text{A}}\) | Avogadro's number |
| \(\N \cdot \m\) | newton-meter (work-energy unit) |
| \(\N \cdot \m\) | newtons times meters (SI unit of torque) |
| \(\text{OE}\) | other energy |
| \(P\) | power |
| \(P\) | power of a lens |
| \(P\) | pressure |
| \(\vb{p}\) | momentum |
| \(p\) | momentum magnitude |
| \(p\) | relativistic momentum |
| \(\vb{p}_{\text{tot}}\) | total momentum |
| \(\vb{p}_{\text{tot}}^{\prime}\) | total momentum some time later |
| \(P_{\text{abs}}\) | absolute pressure |
| \(P_{\text{atm}}\) | atmospheric pressure |
| \(P_{\text{atm}}\) | standard atmospheric pressure |
| \(\PE\) | potential energy |
| \(\PE_{\text{el}}\) | elastic potential energy |
| \(\PE_{\text{elec}}\) | electric potential energy |
| \(\PE_{\s}\) | potential energy of a spring |
| \(P_{\text{in}}\) | power consumption or input |
| \(P_{\text{out}}\) | useful power output going into useful work or a desired, form of energy |
| \(q\) | electron charge |
| \(q_{p}\) | charge of a proton |
| \(q\) | test charge |
| \(\text{QF}\) | quality factor |
| \(R\) | radius of curvature of a spherical mirror |
| \(R\) | resistance |
| \(\vb{R}\) | resultant or total displacement |
| \(R\) | Rydberg constant |
| \(R\) | universal gas constant |
| \(r\) | distance from pivot point to the point where a force is applied |
| \(r_{\perp }\) | perpendicular lever arm |
| \(r\) | radius of a nucleus |
| \(r\) | radius of curvature |
| \(r\) | resistivity |
| \(\text{r or rad}\) | radiation dose unit |
| \(\text{rem}\) | roentgen equivalent man |
| \(\text{rad}\) | radian |
| \(\text{RBE}\) | relative biological effectiveness |
| \(\text{rms}\) | root mean square |
| \(S\) | entropy |
| \(\vb{S}\) | intrinsic spin (intrinsic angular momentum) |
| \(S\) | magnitude of the intrinsic (internal) spin angular momentum |
| \(S\) | shear modulus |
| \(\s\) | second (fundamental SI unit of time) |
| \(s\) | spin quantum number |
| \(\vb{s}\) | total displacement |
| \(\text{sec}\theta\) | secant |
| \(\sin\theta\) | sine |
| \(T\) | period—time to complete one oscillation |
| \(T\) | temperature |
| \(T\) | tension |
| \(t\) | time |
| \(t_{1/2}\) | half-life—the time in which half of the original nuclei decay |
| \(\tan\theta\) | tangent |
| \(U\) | internal energy |
| \(\text{u}\) | unified atomic mass unit |
| \(\vb{u}\) | velocity of an object relative to an observer |
| \(\vb{u}^{\prime}\) | velocity relative to another observer |
| \(V\) | volume |
| \(\vb{v}\) | relative velocity between two observers |
| \(\vb{v}\) | velocity |
| \(\vb{v}_{\text{tot}}\) | total velocity |
| \(v_{\text{w}}\) | propagation speed of sound or other wave |
| \(\vb{v}_{\text{w}}\) | wave velocity |
| \(W\) | work |
| \(W\) | net work done by a system |
| \(\text{W}\) | watt |
| \(w\) | weight |
| \(w_{\text{fl}}\) | weight of the fluid displaced by an object |
| \(W_{\text{c}}\) | total work done by all conservative forces |
| \(W_{\text{nc}}\) | total work done by all nonconservative forces |
| \(W_{\text{out}}\) | useful work output |
| \(X\) | amplitude |
| \(\text{X}\) | symbol for an element |
| \({\text{}}^{Z}X_{N}\) | notation for a particular nuclide |
| \(x\) | deformation or displacement from equilibrium |
| \(x\) | displacement of a spring from its undeformed position |
| \(x\) | horizontal axis |
| \(x_{\text{rms}}\) | root mean square diffusion distance |
| \(y\) | vertical axis |
| \(Y\) | elastic modulus or Young's modulus |
| \(Z\) | atomic number (number of protons in a nucleus) |