User:Garygo golob/Slovene phonology/sandbox
Dimensionless quantities
[edit]Angles
[edit]Angles are dimensionless physical quantities that have its own units, depending on how many dimensions the unit n-sphere has. For example, when drawing an angle on paper, it defines an arc on a unit circle, which has two dimensions. In two dimensions, the unit is radian. In three dimensions, a solid angle defines a part of a surface of a sphere, and the unit is radian squared or steradian. On fandom sites and among hobbyists, the angles are extended for higher dimensions.[1][2]
Scalar quantity | Symbol | Vector-like quantity | Symbol | SI unit | Euclidian space dimension |
---|---|---|---|---|---|
(plane) angle | φ | angular displacement
/ angle of rotation |
θ | radian (rad) | 2 |
solid angle / realm angle | Ω | steradian (sr), square radian (rad2) | 3 | ||
flune angle | Ω4 | cube radian (rad3) | 4 | ||
pentrealm angle | Ω5 | radian to the fourth power (rad4) | 5 | ||
⋮ | |||||
angle in n dimensions | Ωn | radian to the n-th power (radn) | n |
Other dimensionless quantities
[edit]There are many other dimensionless quantities that arise due to simply counting something (decays, pedestrians, rotations, particles etc.) or are ratios, coefficients, factors or moduli of other quantities and the dimensions cancel out. Examples include coefficient of friction, shear strain, specific gravity, and phase.
There is a specific relation between units that are measured with radians and those that are not. If radians are not included, that means the number of full rotations is counted, and not the angles. The factor between the two is hence τ = 2π. A common example for this are frequency (f; measured in 1/s) and angular speed (ω; measured in rad/s), and the relation between them is ω = 2πf.
Geometry and space measurement
[edit]Quantities for measuring space
[edit]Vector quantity | Symbol | Scalar quantity | Symbol | Scalar projection quantity | Symbol | SI unit | Euclidian space dimension | Dimension |
---|---|---|---|---|---|---|---|---|
displacement | x | arc length / edge length[1] | s | distance | d | m | 1 | L |
vector area | S | surface area | A | (planar) area | A | m2 | 2 | L2 |
vector volume | V | surcell volume[3] | V | volume | V | m3 | 3 | L3 |
vector bulk | surteron bulk[4] | bulk[4] | m4 | 4 | L4 | |||
⋮ | ||||||||
breadth in n dimensions | mn | n | Ln |
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
altitude | h | Line segment perpendicularly connecting a side of a triangle or its extension to the opposite vertex. | scalar | m | L |
amplitude (in length) | u | A measure of its change in a single period. | scalar | m | L |
bimedian | Line segment connecting the midpoints of opposite sides in a quadrilateral. | scalar | m | L | |
breadth | A relatively large width. | scalar | m | L | |
chord | Line segment connecting two points on a circle or sphere. | scalar | m | L | |
curvature (by the radius) | κ | The amount by which a curve deviates from being a straight line or by which a surface deviates from being a plane; derived from the radius of a best-fit circle. | scalar | m-1 | L-1 |
curvature (by the arc) | κ | The amount by which a curve deviates from being a straight line or by which a surface deviates from being a plane; derived from the rate of change of angle. | scalar | rad. m-1 | L-1 |
diagonal | d | A line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. | scalar | m | L |
diameter | d | Any straight line segment that passes through the centre of the circle or sphere and whose endpoints lie on the circle or sphere. | scalar | m | L |
edge | a or b etc. | Line segment joining two vertices in a polygon, polyhedron, or higher-dimensional polytope. | scalar | m | L |
face | A flat surface (a planar region) that forms part of the boundary of a solid object | scalar | m2 | L2 | |
first moment of area | S | Measure of the spatial distribution of a shape in relation to an axis. | scalar | m3 | L3 |
height and depth | h | Distance perpendicular to gravitational potential lines. | scalar | m | L |
hypotenuse | h | Longest side in a right-angle triangle. | scalar | m | L |
length | l | Distance along the longest dimension of an object. | scalar | m | L |
maltitude | Line segment perpendicularly connecting one side to the midpoint of the opposite side in a quadrilateral. | scalar | m | L | |
median | Line segment connecting a side's midpoint to the opposite vertex in a triangle. | scalar | m | L | |
peak amplitude (in length) | û | If the reference is zero, this is the maximum absolute value of the signal. | scalar | m | L |
peak-to-peak amplitude (in length) | p-p | the change between peak (highest amplitude value) and trough (lowest amplitude value, which can be negative). | scalar | m | L |
placement[5] | The inverse of distance. | scalar | m-1 | L-1 | |
radius | r | Distance from the center to a point on a circle or a sphere. | scalar | m | L |
root mean square amplitude (in length) | ûRMS | The square root of the mean over time of the square of the vertical distance of the graph from the rest state. | scalar | m | L |
second moment of area / area moment of inertia | I or J | Geometrical property of an area which reflects how its points are distributed with regard to an arbitrary axis. | scalar | m4 | L4 |
semi-amplitude (in length) | Half the peak-to-peak amplitude. | scalar | m | L | |
signed curvature (by the radius) | k | Curvature with the side of curving taken into account. | pseudoscalar | m-1 | L-1 |
signed curvature (by the arc) | k | Curvature with the side of curving taken into account. | pseudoscalar | rad m-1 | L-1 |
width | w | Shorter of the two dimensions of an object. | scalar | m | L |
Translational kinematics
[edit]Derivatives and antiderivatives of distance and displacement
[edit]In the table are given the derivatives and antiderivatives of displacement (vector) and distance (scalar).[5]
Vector quantity | Symbol | Scalar quantity | Symbol | SI unit | Dimension |
---|---|---|---|---|---|
absut / absput | m s11 | L T11 | |||
abshot | m s10 | L T10 | |||
absrop | m s9 | L T9 | |||
absock | m s8 | L T8 | |||
absop | m s7 | L T7 | |||
absrackle | m s6 | L T6 | |||
absounce | m s5 | L T5 | |||
abserk | D | m s4 | L T4 | ||
abseleration | C | m s3 | L T3 | ||
absity | B | m s2 | L T2 | ||
absement / absition | A | A | m s | L T | |
displacement | x | distance | d | m | L |
velocity | v | speed | v | m s-1 | L T-1 |
acceleration | a | acceleration and deceleration | a | m s-2 | L T-2 |
jerk/jolt/surge/lurch | j | m s-3 | L T-3 | ||
jounce/snap | s | m s-4 | L T-4 | ||
crackle | c | m s-5 | L T-5 | ||
pop/dork | p | m s-6 | L T-6 | ||
lock | m s-7 | L T-7 | |||
drop | m s-8 | L T-8 | |||
shot | m s-9 | L T-9 | |||
put | m s-10 | L T-10 |
Antiderivatives of placement
[edit]Antiderivatives of placement or reciprocals of derivatives of distance bear the prefix pre- and are only scalar:[5]
Scalar quantity | SI unit | Dimension |
---|---|---|
presput | m-1 s11 | L-1 T11 |
preshot | m-1 s10 | L-1 T10 |
presrop | m-1 s9 | L-1 T9 |
presock | m-1 s8 | L-1 T8 |
presop | m-1 s7 | L-1 T7 |
presackle | m-1 s6 | L-1 T6 |
presounce | m-1 s5 | L-1 T5 |
preserk | m-1 s4 | L-1 T4 |
preseleration | m-1 s3 | L-1 T3 |
presity | m-1 s2 | L-1 T2 |
presement / pace | m-1 s | L-1 T |
placement | m-1 | L-1 |
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
duration | Δt | Time needed to accomplish something. | scalar | s | T |
gravity | g | Acceleration due to weight. | vector | m s-2 | L T-2 |
pace | Inverse of velocity or speed. | vector or scalar | m-1 s | L-1 T | |
relative velocity | vB|A | Velocity in relation to another (moving) object. | vector | m s-1 | L T-1 |
terminal velocity | vt | Highest velocity attainable by a free falling object. | vector | m s-1 | L T-1 |
Angular kinematics & acoustics
[edit]Time derivatives and antiderivatives of angle
[edit]Pseudovector quantity | Symbol | Scalar quantity | Symbol | SI unit | Dimension |
---|---|---|---|---|---|
angular absut/absput | rad s11 | T11 | |||
angular abshot | rad s10 | T10 | |||
angular absrop | rad s9 | T9 | |||
angular absock | rad s8 | T8 | |||
angular absop | rad s7 | T7 | |||
angular absrackle | rad s6 | T6 | |||
angular absounce | rad s5 | T5 | |||
angular abserk | rad s4 | T4 | |||
angular abseleration | rad s3 | T3 | |||
angular absity | rad s2 | T2 | |||
angular absement / anglement | rad s | T | |||
angular displacement | θ | angle | φ | rad | 1 |
angular velocity | ω | angular speed | ω | rad s-1 | T-1 |
angular acceleration | α | angular chirpyness | γ | rad s-2 | T-2 |
angular jerk/jolt/surge/lurch | ζ | rad s-3 | T-3 | ||
angular jounce/snap | ψ | rad s-4 | T-4 | ||
angular crackle | rad s-5 | T-5 | |||
angular pop/dork | rad s-6 | T-6 | |||
angular lock | rad s-7 | T-7 | |||
angular drop | rad s-8 | T-8 | |||
angular shot | rad s-9 | T-9 | |||
angular put | rad s-10 | T-10 |
Time derivatives and antiderivatives of no. of rotations
[edit]Pseudovector quantity | Symbol | Scalar quantity | Symbol | SI unit | Dimension |
---|---|---|---|---|---|
rotational absut/absput | s11 | T11 | |||
rotational abshot | s10 | T10 | |||
rotational absrop | s9 | T9 | |||
rotational absock | s8 | T8 | |||
rotational absop | s7 | T7 | |||
rotational absrackle | s6 | T6 | |||
rotational absounce | s5 | T5 | |||
rotational abserk | s4 | T4 | |||
rotational abseleration | s3 | T3 | |||
rotational absity | s2 | T2 | |||
rotational absement | s | T | |||
rotational displacement | N | no. of rotations | N | 1 | |
rotational velocity | ν | rotational speed / rotational frequency | ν | s-1 | T-1 |
rotational acceleration | ordinary chirpyness | c | s-2 | T-2 | |
rotational jerk/jolt/surge/lurch | s-3 | T-3 | |||
rotational jounce/snap | s-4 | T-4 | |||
rotational crackle | s-5 | T-5 | |||
rotational pop/dork | s-6 | T-6 | |||
rotational lock | s-7 | T-7 | |||
rotational drop | s-8 | T-8 | |||
rotational shot | s-9 | T-9 | |||
rotational put | s-10 | T-10 |
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
acoustic admittance | Y | Inverse of acoustic impedance. | scalar | Pa-1 s-1 m3 | M-1 L4 T1 |
acoustic conductance | G | Real part of acoustic admittance. | scalar | Pa-1 s-1 m3 | M-1 L4 T1 |
acoustic impedance | Z | Measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. | scalar | Pa s m-3 | M L-4 T-1 |
acoustic reactance | X | Imaginary part of acoustic impedance. | scalar | Pa s m-3 | M L-4 T-1 |
acoustic resistance | R | Real part of acoustic impedance. | scalar | Pa s m-3 | M L-4 T-1 |
acoustic susceptance | B | Imaginary part of acoustic admittance. | scalar | Pa-1 s-1 m3 | M-1 L4 T1 |
acoustic volume flow rate | Q | Flow rate due to longitudinal waves. | scalar | m3 s-1 | L3 T-1 |
amplitude (in length) | u | A measure of its change in a single period. | scalar | m | L |
amplitude (in pressure) | u | A measure of its change in a single period. Used for longitudinal waves. | scalar | Pa | M L-1 T-2 |
angular wavelength / reduced wavelength | ƛ | Wavelength divided by 2π. | scalar | m rad-1 | L |
angular wavenumber | k | Wavenumber divided by 2π. | scalar | rad m-1 | L-1 |
audio frequency | A periodic vibration whose frequency is audible to the average human. | scalar | Hz | T-1 | |
bandwith | B | The difference between the upper and lower frequencies in a continuous band of frequencies. | scalar | Hz | T-1 |
capacitive acoustic reactance | XC | Negative part of acoustic reactance. | scalar | Pa s m-3 | M L-4 T-1 |
cenrifugal acceleration | Acceleration due to centrifugal force. | vector | m s-2 | L T-2 | |
centripetal acceleration | ac | Acceleration due to centripetal force. | vector | m s-2 | L T-2 |
Coriolis acceleration | Acceleration due to Coriolis force. | vector | m s-2 | L T-2 | |
Coriolis frequency | f | Frequency of inertial oscillation resulting from Coriolis effect. | scalar | Hz | T-1 |
duration | Δt | Time needed to accomplish something. | scalar | s | T |
Euler acceleration | aEuler | Part of the absolute acceleration that is caused by the variation in the angular velocity of the reference frame. | vector | m s-2 | L T-2 |
frequency | f | Number of oscillations per unit time. | scalar | Hz | T-1 |
frequency drift | Offset of an oscillator from its nominal frequency. | scalar | Hz s-1 | T-2 | |
front velocity | vf | The speed at which the first rise of a pulse above zero moves forward. | vector | m s-2 | L T-2 |
group velocity | vg | The velocity with which the overall envelope shape of the wave's amplitudes—known as the modulation or envelope of the wave—propagates through space. | vector | m s-2 | L T-2 |
inductive acoustic reactance | XL | Positive part of acoustic reactance. | scalar | Pa s m-3 | M L-4 T-1 |
longitudinal modulus / P-wave modulus | M | A relation between the density of a material and the speed of P-waves traveling through it. | scalar | Pa | M L-1 T-2 |
mechanical wave energy | Energy due to the oscillations within a material (longitudinal or transverse). | scalar | J | M L2 T-2 | |
mechanical wave energy density | Mechanical wave energy per unit volume. | scalar | J m-3 | M L-1 T-2 | |
mechanical wave intensity | I | The power carried by mechanical waves per unit area in a direction perpendicular to that area. | scalar | W m-2 | M T-3 |
mechanical wave power | Power due to the oscillations within a material (longitudinal or transverse). | scalar | W | M L2 T-3 | |
mechanical wave pressure | The local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a mechanical wave. | scalar | Pa | M L-1 T-2 | |
peak amplitude (in length) | û | If the reference is zero, this is the maximum absolute value of the wave. | scalar | m | L |
peak amplitude (in pressure) | If the reference is zero, this is the maximum absolute value of the wave. Used for longitudinal waves. | scalar | Pa | M L-1 T-2 | |
peak-to-peak amplitude (in length) | p-p | the change between peak (highest amplitude value) and trough (lowest amplitude value, which can be negative). | scalar | m | L |
peak-to-peak amplitude (in pressure) | p-p | the change between peak (highest amplitude value) and trough (lowest amplitude value, which can be negative). Used for longitudinal waves. | scalar | Pa | M L-1 T-2 |
phase velocity | vp | The rate at which the wave propagates in any medium. | vector | m s-1 | L T-1 |
pulse wave velocity | PWV | The velocity at which a pulse travels through a medium. | vector | m s-1 | L T-1 |
radius of gyration | r | The radial distance to a point which would have a moment of inertia the same as the body's actual distribution of mass, if the total mass of the body were concentrated there. Usually includes different powers of radians to cancel out, e.g. rad-1 to convert from angular velocity to velocity and rad-½ to cancel out when multiplying angular velocity and moment of inertia. | scalar | m radx | L |
root mean square amplitude (in length) | ûRMS | The square root of the mean over time of the square of the vertical distance of the graph from the rest state. | scalar | m | L |
root mean square amplitude (in pressure) | ûRMS | The square root of the mean over time of the square of the vertical distance of the graph from the rest state. Used for longitudinal waves. | scalar | Pa | M L-1 T-2 |
rotation period | T | The time that the object takes to complete a full rotation. | scalar | s | T |
semi-amplitude (in length) | Half the peak-to-peak amplitude. | scalar | m | L | |
semi-amplitude (in pressure) | Half the peak-to-peak amplitude. Used for longitudinal waves. | scalar | Pa | M L-1 T-2 | |
signal velocity | vs | The speed at which a wave carries information. | vector | m s-1 | L T-1 |
spatial frequency | ξ | The inverse of wavelength. | scalar | m-1 | L-1 |
sound energy | Energy due to a longitudinal wave. | scalar | J | M L2 T-2 | |
sound energy density | Sound energy per unit volume. | scalar | J m-3 | M L-1 T-2 | |
sound exposure | The integral, over time, of squared sound pressure. | scalar | Pa2 s | M2 L-2 T-3 | |
sound intensity | The power carried by sound waves per unit area in a direction perpendicular to that area. | scalar | W m-2 | M T-3 | |
sound power | Power due to a longitudinal wave. | scalar | W | M L2 T-3 | |
sound pressure | The local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. | scalar | Pa | M L-1 T-2 | |
specific acoustic admittance | y | Inverse of specific acoustic impedance. | scalar | Pa-1 s-1 m | M-1 L2 T1 |
specific acoustic conductance | g | Real part of specific acoustic admittance. | scalar | Pa-1 s-1 m | M-1 L2 T1 |
specific acoustic impedance | z | Measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. | scalar | Pa s m-1 | M L-2 T-1 |
specific acoustic reactance | x | Imaginary part of specific acoustic impedance. | scalar | Pa s m-1 | M L-2 T-1 |
specific acoustic resistance | r | Real part of specific acoustic impedance. | scalar | Pa s m-1 | M L-2 T-1 |
specific acoustic susceptance | b | Imaginary part of specific acoustic admittance. | scalar | Pa-1 s-1 m | M-1 L2 T1 |
specific capacitive acoustic reactance | xC | Negative part of specific acoustic reactance. | scalar | Pa s m-1 | M L-2 T-1 |
specific inductive acoustic reactance | xL | Positive part of specific acoustic reactance. | scalar | Pa s m-1 | M L-2 T-1 |
spectral energy density | S̄xx | Energy of a wave per frequency. | scalar | J Hz-1 | M L2 T-1 |
spectral power density | Sxx | Power of a wave per frequency. | scalar | W Hz-1 | M L2 T-2 |
speed of sound | c | The distance travelled per unit of time by a sound wave as it propagates through an elastic medium. | scalar | m s-1 | L T-1 |
tangential acceleration | at | Acceleration perpendicular to the radius of gyration, parallel to the velocity. | vector | m s-2 | L T-2 |
time | t | One of the base units. | scalar | s | T |
wave speed | Magnitude of one of the different velocities for measuring waves. | scalar | m s-1 | L T-1 | |
wave velocity | One of the different velocities for measuring waves. | scalar | m s-1 | L T-1 | |
wavelength | λ | Distance over which the wave's shape repeats. | scalar | m | L |
wavenumber / repetancy | ν | The inverse of wavelength, but only limited to waves; elsewhere, spatial frequency is used. | scalar | m-1 | L-1 |
Translational mechanics
[edit]Derivatives and antiderivatives of force
[edit]Vector / scalar quantity | Symbol | SI unit | Dimension | |
---|---|---|---|---|
Vector | Scalar | |||
momentement | kg m | M L | ||
momentum | p | p | kg m s-1 | M L T-1 |
force | F | F | N | M L T-2 |
yank[5] | Y | Y | N s-1 | M L T-3 |
tug[5] | T | T | N s-2 | M L T-4 |
snatch[5] | S | S | N s-3 | M L T-5 |
shake[5] | Sh | Sh | N s-4 | M L T-6 |
Derivatives and antiderivatives of energy
[edit]Hamiltonian scalar | Symbol | Lagrangian scalar | Symbol | SI unit | Dimension |
---|---|---|---|---|---|
integral of action | I[6] | J s2 | M L2 | ||
actergy | action | S | J s | M L2 T-1 | |
energy | E | J | M L2 T-2 | ||
power | P | W | M L2 T-3 | ||
power consumption[7] | W s-1 | M L2 T-4 |
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
mass | m | One of the basic quantities. | scalar | kg | M |
drag | Fdrag | Force opposing the motion in a fluid. | vector | N | M L T-2 |
dynamic force | Fd | Component of weight parallel to the slope. | vector | N | M L T-2 |
dynamic friction | Friction acting on a moving object. | vector | N | M L T-2 | |
elastic potential energy | Eel | Energy due to the deformation of objects. | scalar | J | M L2 T-2 |
friction | Ff | Force opposing motion. | vector | N | M L T-2 |
gravitational field work | Wg | Work done by the gravitational field. | scalar | J | M L2 T-2 |
gravitational force | Fg | Force due to the gravitational attraction. | vector | N | M L T-2 |
gravitational potential energy | Eg | Energy gained due to the gravitational field work. | scalar | J | M L2 T-2 |
internal energy | U | Energy inside a system. | scalar | J | M L2 T-2 |
kinetic energy | Ek | Energy due to movement. | scalar | J | M L2 T-2 |
normal force | N | The component of a contact force that is perpendicular to the surface that an object contacts. | vector | N | M L T-2 |
potential energy | Ep | Energy stored (e.g. due to a field or by stretching a material) and can be turned into another form. | scalar | J | M L2 T-2 |
pressure | p | Force exerted over an area | scalar | Pa | M L-1 T-2 |
specific force | SF | Quotient of force and mass. | vector or scalar | N kg-1 | L T-2 |
specific power | PWR | Power delivered by unit mass. | scalar | W kg-1 | L2 T-3 |
specific weight | γ (scalar)
γ (vector) |
Density times gravitational field strength (scalar) or weight per unit volume (vector). | scalar or vector | N m-3 | M L-2 T-2 |
static force | Fs | Component of weight perpendicular to slope. | vector | N | M L T-2 |
static friction | Friction acting on a stationary object. | vector | N | M L T-2 | |
tension force | Ftension | Collinear shearing forces. | vector | N | M L T-2 |
virtual displacement | δγ | It shows how the mechanical system's trajectory can hypothetically deviate very slightly from the actual trajectory of the system without violating the system's constraints. | vector | m | L |
virtual work | δW | Work done by a force to move a particle along a virtual displacement | scalar | J | M L2 T-2 |
weight | W (vector)
W (scalar) |
Force due to the gravitational attraction (vector) or its magnitude (scalar). Usually used for objects with negligible effect on gravitational field. See also gravitational force. | vector or scalar | N | M L T-2 |
work | W | Energy transferred to an object or from it. | scalar | J | M L2 T-2 |
Angular mechanics
[edit]Torque and its derivatives and antiderivatives
[edit]Pseudovector quantity | Symbol | SI unit | Dimension |
---|---|---|---|
moment of momentement | N m s2 | M L2 | |
angular momentum / moment of momentum | L | N m s | M L2 T-1 |
torque / moment of force | τ | N m | M L2 T-2 |
rotatum / moment of yank | N m s-1 | M L2 T-3 | |
moment of tug | N m s-2 | M L2 T-4 | |
moment of snatch | N m s-3 | M L2 T-5 | |
moment of shake | N m s-4 | M L2 T-6 |
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
angular drag coefficient[8] | γ | Coefficient of how much a fluid hinders the rotation of an object. | scalar | kg m2 s-1 | M L2 T-1 |
centrifugal force | Inertial force that appears to act on all objects when viewed in a rotating frame of reference. | vector | N | M L T-2 | |
centripetal force | Fc | Force causing rotation. | vector | N | M L T-2 |
Coriolis force | An inertial force that acts on objects in motion within a frame of reference that rotates with respect to an inertial frame. | vector | N | M L T-2 | |
Euler force | FEuler | The fictitious tangential force that appears when a non-uniformly rotating reference frame is used for analysis of motion and there is variation in the angular velocity of the reference frame's axes. | vector | N | M L T-2 |
friction torque | Torque of a frictional force. | vector | N m | M L2 T-2 | |
internal energy | U | Energy inside a system. | scalar | J | M L2 T-2 |
mass | m | One of the basic quantities. | scalar | kg | M |
mechanical energy | Sum of potential and kinetic energies. | scalar | J | M L2 T-2 | |
moment of inertia | I | A quantity that determines the torque needed for a desired angular acceleration about a rotational axis, akin to how mass determines the force needed for a desired acceleration. | scalar | kg m2 | M L2 |
rotational energy | Er | Energy due to rotation of an object. | scalar | J | M L2 T-2 |
specific angular momentum | h | Angular momentum per unit mass. | vector | N m s kg-1 | L2 T-1 |
specific torque | Torque per unit mass. | vector | N m kg-1 | L2 T-2 | |
specific power | PWR | Power delivered by unit mass. | scalar | W kg-1 | L2 T-3 |
tangential force | Force causing tangential acceleration. | vector | N | M L T-2 |
Solid mechanics and engineering
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
area density / column density | ρA | Mass per unit area. | scalar | kg m-2 | M L-2 |
area thermal expansion | ΔA | Change in area due to a change in temperature. | scalar | m2 | L2 |
area thermal expansion coefficient | αA | Area thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
bulk modulus | K | A measure of the resistance of a substance to bulk compression. | scalar | Pa | M L-1 T-2 |
coefficient of linear thermal expansion | αL | Linear thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
compressibility (isentropic) | βS | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isentropic process. | scalar | Pa-1 | M-1 L T2 |
compressibility (isothermal) | βT | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isothermal process. | scalar | Pa-1 | M-1 L T2 |
compressive strength | The capacity of a material or structure to withstand loads tending to reduce size. | scalar | Pa | M L-1 T-2 | |
compressive stress | Stress that causes compression. | scalar | Pa | M L-1 T-2 | |
deflection | w | The degree to which a part of a long structural element (such as beam) is deformed laterally (in the direction transverse to its longitudinal axis) under a load. See also elastic deflection. | scalar | m | L-1 |
density | ρ | Mass per unit volume. | scalar | kg m-3 | M L-3 |
density change | ρ̇ | A measure of density increase or decrease with time. | scalar | kg m-3 s-1 | M L-3 T-1 |
dislocation density (per area) | ρ⟂ | Number of dislocations per unit area. | scalar | m-2 | L-2 |
dislocation density (per volume) | Number of dislocations per unit volume. | scalar | m-3 | L-3 | |
elastic deflection | δ | Reversible deflection, proportional to the load. | scalar | m | L |
elastic modulus | δ | The unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it. Exists in many different forms; all but Poisson's ratio have this unit and dimension as listed here. | scalar | Pa | M L-1 T-2 |
elastic potential energy | Eel | Energy due to the deformation of objects. | scalar | J | M L2 T-2 |
energy release rate | G | The rate at which energy is transformed as a material undergoes fracture. | scalar | J m-2 | M T-2 |
engineering stress | σe | Stress without taking changes in area due to deformation into account. | scalar | Pa | M L-1 T-2 |
expansion rate | Rate at which a substance is expanding. | scalar | s-1 | T-1 | |
flaw length | a | Half the length of a crack. | scalar | m | L |
flexural modulus | Eflex | An intensive property that is computed as the ratio of stress to strain in flexural deformation. | scalar | Pa | M L-1 T-2 |
flexural strength | The stress in a material just before it yields in a flexure test. | scalar | Pa | M L-1 T-2 | |
fracture stress | σf | Stress at which a structure fails. | scalar | Pa | M L-1 T-2 |
fracture toughness | Kc | The critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited. | scalar | Pa m½ | M L-½ T-2 |
hardness | H | A measure of the resistance to localized plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by pressing or abrasion. | scalar | Pa | M L-1 T-2 |
J-integral | J | A way to calculate the strain energy release rate, or work (energy) per unit fracture surface area, in a material. | scalar | Pa m½ | M L-½ T-2 |
Lamé's first parameter | λ | Stiffness of a fluid when compressed in one direction and limited in other directions. | scalar | Pa | M L-1 T-2 |
linear deformation | Δl | Changes in length due to stress. | scalar | m | L |
linear (mass) density | λ | Mass per unit length, e.g. of wire. | scalar | kg m-1 | M L-1 |
linear thermal expansion | Δd | Change in length due to a change in temperature. | scalar | m | L |
linearly distributed load | q | Load distributed over the distance of an object. | scalar | N m-1 | M T-2 |
load | q | Force(s) causing stress. | scalar | N | M L T-2 |
longitudinal modulus / P-wave modulus | M | A relation between the density of a material and the speed of P-waves traveling through it. | scalar | Pa | M L-1 T-2 |
modulus of resilience | Ur | The maximum energy that can be absorbed per unit volume without creating a permanent distortion. | scalar | J m-3 = Pa | M L-1 T-2 |
modulus of rigidity / shear modulus / Lamé's second parameter | G or μ | A measure of the elastic shear stiffness of a material. | scalar | Pa | M L-1 T-2 |
plain strain fracture toughness | KIc | The critical stress intensity factor of a sharp crack where propagation of the crack suddenly becomes rapid and unlimited. Used for mode I cracks. | scalar | Pa m½ | M L-½ T-2 |
proof resilience | The maximum energy that can be absorbed up to the elastic limit, without creating a permanent distortion. | scalar | J | M L2 T-2 | |
proof stress | Rp | The value for this is commonly set at 0.1% or 0.2% plastic strain. | scalar | Pa | M L-1 T-2 |
proportionality limit stress | Up to this amount of stress, stress is proportional to strain (Hooke's law). | scalar | Pa | M L-1 T-2 | |
reduced modulus | Er | A special relation between the Young's moduli and Poisson's ratios of the sample and the indenter, used for measuring hardness. | scalar | Pa | M L-1 T-2 |
shear force | Fshear | Unaligned forces acting on one part of a body in a specific direction, and another part of the body in the opposite direction. | vector | N | M L T-2 |
shear rate | γ̇ | The rate at which it is being deformed by progressive shearing without changing its volume. | scalar | s-1 | T-1 |
shear stiffness | The extent to which an object resists deformation in response to applied shear forces. | scalar | N | M L T-2 | |
shear strength | The strength of a material or component against the type of yield or structural failure when the material or component fails in shear. | scalar | Pa | M L-1 T-2 | |
shear stress | τ | The component of stress coplanar with a material cross section. | scalar | Pa | M L-1 T-2 |
specific area[9] | Area of an object (e.g. textile) per unit mass. | scalar | m2 kg-1 | M-1 L2 | |
specific length[10] | Length of an object (e.g. wire) per unit mass. | scalar | m kg-1 | M-1 L | |
specific volume | ν | Volume of an object per unit mass. Inverse of density. | scalar | m3 kg-1 | M-1 L3 |
static moment of area | Q | Property of a shape that is used to predict its resistance to shear stress. | scalar | m3 | L3 |
stiffness / spring constant | k | The extent to which an object resists deformation in response to an applied force. | scalar | N m-1 | M T-2 |
strain energy | U | Elastic potential energy gained by a wire during elongation with a tensile (stretching) or compressive (contractile) force. | scalar | J | M L2 T-2 |
strain rate | ε̇ | Time derivative of strain. | scalar | s-1 | T-1 |
stress | σ | The force across a small boundary per unit area of that boundary, for all orientations of the boundary. | scalar | Pa | M L-1 T-2 |
stress intensity factor | K | Used to predict the stress state ("stress intensity") near the tip of a crack or notch caused by a remote load or residual stresses. | scalar | Pa m½ | M L-½ T-2 |
surface energy density | γ | Energy per unit area. | scalar | J m-2 | M T-2 |
tangent modulus | The slope of the stress–strain curve at any specified stress or strain, even in the plastic region. | scalar | Pa | M L-1 T-2 | |
tensile strength | The capacity of a material or structure to withstand loads tending to reduce size. | scalar | Pa | M L-1 T-2 | |
tensile stress | Stress that causes elongation. | scalar | Pa | M L-1 T-2 | |
torsion constant | J | It describes a bar's torsional stiffness. | scalar | m4 rad-1 | L4 |
torsion | T | The twisting of an object due to an applied torque. | scalar | Pa | M L-1 T-2 |
torsional rigidity | Product of shear modulus and torsion constant. | scalar | N m2 rad-1 | M L3 T-2 | |
torsional stiffness | τ[11] | The extent to which an object resists deformation in response to an applied torque. | scalar | N m rad-1 | M L2 T-2 |
toughness / deformation energy | UT | The ability of a material to absorb energy and plastically deform without fracturing. | scalar | J m-3 = Pa | M L-1 T-2 |
true elastic limit | The lowest stress at which dislocations move. | scalar | Pa | M L-1 T-2 | |
ultimate tensile strength | Ftu | The maximum stress that a material can withstand while being stretched or pulled before breaking. | scalar | Pa | M L-1 T-2 |
volumetric deformation | ΔV | Changes in volume due to stress (expansion and compression due to pressure changes). | scalar | m3 | L3 |
volumetric thermal expansion | ΔV | Change in volume due to a change in temperature. | scalar | m3 | L3 |
volumetric thermal expansion coefficient | αV | Volumetric thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
yield stress / yield strength | The lowest stress at which permanent deformation can be measured. | scalar | Pa | M L-1 T-2 | |
Young's modulus | E | A mechanical property of solid materials that measures the tensile or compressive stiffness when the force is applied lengthwise. | scalar | Pa | M L-1 T-2 |
Fluid mechanics
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
apparent thermal expansion | Apparent thermal expansion of a fluid that is partially due to the expansion of a container. | scalar | m3 | L3 | |
area density / column density | ρA | Mass per unit area. | scalar | kg m-2 | M L-2 |
buoyancy | Fb | An upward force exerted by a fluid that opposes the weight of a partially or fully immersed object. | vector | N | M L T-2 |
coefficient of apparent expansion | Apparent expansion of a liquid per unit temperature. | scalar | K-1 | Θ-1 | |
compressibility (isentropic) | βS | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isentropic process. | scalar | Pa-1 | M-1 L T2 |
compressibility (isothermal) | βT | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isothermal process. | scalar | Pa-1 | M-1 L T2 |
compressive strength | The capacity of a material or structure to withstand loads tending to reduce size. | scalar | Pa | M L-1 T-2 | |
compressive stress | Stress that causes compression. | scalar | Pa | M L-1 T-2 | |
density | ρ | Mass per unit volume. | scalar | kg m-3 | M L-3 |
density change | ρ̇ | A measure of density increase or decrease with time. | scalar | kg m-3 s-1 | M L-3 T-1 |
drag | Fdrag | Force opposing the motion in a fluid. | vector | N | M L T-2 |
dynamic modulus | G | The ratio of stress to strain under vibratory conditions. | scalar | Pa | M L-1 T-2 |
dynamic viscosity / shear viscosity | μ or η | A material property which relates the viscous stresses in a material to the rate of change of a deformation (the strain rate). | scalar | Pa s | M L-1 T-1 |
electron density | ne | Density of electrons in plasma. | scalar | mol m-3 | L-3 N |
entropic force | F | An emergent phenomenon resulting from the entire system's statistical tendency to increase its entropy, rather than from a particular underlying force on the atomic scale. | vector | N | M L T-2 |
expansion rate | Rate at which a substance is expanding. | scalar | s-1 | T-1 | |
flow velocity gradient | Differences in velocity over distance in a fluid. | scalar | s-1 | T-1 | |
force density | f | Force per unit volume. | vector | N m-3 | M L-2 T-2 |
fugacity | f | An effective partial pressure which replaces the mechanical partial pressure in an accurate computation of chemical equilibrium. | scalar | Pa | M L-1 T-2 |
fugacity capacity | Z | Molar concentration divided by fugacity. | scalar | mol m-3 Pa-1 | N M-1 L-2 T2 |
hydrostatic pressure | p | Pressure in a fluid at a certain depth. | scalar | Pa | M L-1 T-2 |
hydrostatic pressure gradient | Change of hydrostatic pressure with depth. | scalar | Pa m-1 | M L-2 T-2 | |
ion density | ni | Density of ions in plasma. | scalar | mol m-3 | L-3 N |
kinematic viscosity | ν | Dynamic viscosity divided by the density of a fluid. | scalar | J s kg-1 | L2 T-1 |
linear (mass) density | λ | Mass per unit length. | scalar | kg m-1 | M L-1 |
load | Force(s) causing stress. | scalar | N | M L T-2 | |
longitudinal modulus / P-wave modulus | M | A relation between the density of a material and the speed of P-waves traveling through it. | scalar | Pa | M L-1 T-2 |
loss modulus | G″ | Relation between stress and heat released under vibratory conditions. | scalar | Pa | M L-1 T-2 |
mass diffusivity | D | Tendency of a substance to diffuse. | scalar | m2 s-1 | L2 T-1 |
mass flow acceleration | m̈ | Acceleration of mass flow rate. | scalar | kg s-2 | M T-2 |
mass flow rate | ṁ | Rate of flow in regard to mass. | scalar | kg s-1 | M T-1 |
mass flux | j or J | The rate of mass flow per unit of area. | scalar | kg m-2 s-1 | M L-2 T-1 |
molar volume | Vm | Volume occupied by a unit amount. Used for calculating the thermal expansion of gases. | scalar | m3 mol-1 | N-1 L3 |
neutral density | nn | Density of neutral particles in plasma. | scalar | mol m-3 | L-3 N |
shear rate | γ̇ | The rate at which it is being deformed by progressive shearing without changing its volume. | scalar | s-1 | T-1 |
shear velocity / friction velocity | u | A form by which a shear stress may be re-written in units of velocity. | usually scalar | m s-1 | L T-1 |
specific area[9] | Area of a fluid per unit mass. | scalar | m2 kg-1 | M-1 L2 | |
specific length[10] | Length of a fluid per unit mass. | scalar | m kg-1 | M-1 L | |
specific volume | ν | Volume of a fluid per unit mass. Inverse of density. | scalar | m3 kg-1 | M-1 L3 |
storage modulus | G′ | Relation between stress and stored energy in vibratory conditions. | scalar | Pa | M L-1 T-2 |
stress | σ | The force across a small boundary per unit area of that boundary, for all orientations of the boundary. | scalar | Pa | M L-1 T-2 |
surface tension | γ | the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. | scalar | N m-1 | M T-2 |
vapor concentration (by mass) | C*[12] | Concentration of vapor of a substance in the air. | scalar | kg m-3 | M L-3 |
vapor concentration (by amount) | Concentration of vapor of a substance in the air. | scalar | mol m-3 | N L-3 | |
volume viscosity / bulk viscosity | ζ | The irreversible resistance, over and above the reversible resistance caused by isentropic bulk modulus, to a compression or expansion of a fluid. | scalar | Pa s | M L-1 T-1 |
volumetric deformation | ΔV | Changes in volume due to stress (expansion and compression due to pressure changes). | scalar | m3 | L3 |
volumetric flow acceleration | V̈ | Acceleration of volumetric flow rate. | scalar | m3 s-2 | L3 T-2 |
volumetric flow rate | φ | Rate of flow in regard to volume. | scalar | m3 s-1 | L3 T-1 |
volumetric thermal expansion | ΔV | Change in volume due to a change in temperature. | scalar | m3 | L3 |
volumetric thermal expansion coefficient | αV | Absolute thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
Optics
[edit]Radiometry
[edit]
Quantity | Unit | Dimension | Notes | ||
---|---|---|---|---|---|
Name | Symbol[nb 1] | Name | Symbol | ||
Radiant energy | Qe[nb 2] | joule | J | M⋅L2⋅T−2 | Energy of electromagnetic radiation. |
Radiant energy density | we | joule per cubic metre | J/m3 | M⋅L−1⋅T−2 | Radiant energy per unit volume. |
Radiant flux | Φe[nb 2] | watt | W = J/s | M⋅L2⋅T−3 | Radiant energy emitted, reflected, transmitted or received, per unit time. This is sometimes also called "radiant power", and called luminosity in Astronomy. |
Spectral flux | Φe,ν[nb 3] | watt per hertz | W/Hz | M⋅L2⋅T −2 | Radiant flux per unit frequency or wavelength. The latter is commonly measured in W⋅nm−1. |
Φe,λ[nb 4] | watt per metre | W/m | M⋅L⋅T−3 | ||
Radiant intensity | Ie,Ω[nb 5] | watt per steradian | W/sr | M⋅L2⋅T−3 | Radiant flux emitted, reflected, transmitted or received, per unit solid angle. This is a directional quantity. |
Spectral intensity | Ie,Ω,ν[nb 3] | watt per steradian per hertz | W⋅sr−1⋅Hz−1 | M⋅L2⋅T−2 | Radiant intensity per unit frequency or wavelength. The latter is commonly measured in W⋅sr−1⋅nm−1. This is a directional quantity. |
Ie,Ω,λ[nb 4] | watt per steradian per metre | W⋅sr−1⋅m−1 | M⋅L⋅T−3 | ||
Radiance | Le,Ω[nb 5] | watt per steradian per square metre | W⋅sr−1⋅m−2 | M⋅T−3 | Radiant flux emitted, reflected, transmitted or received by a surface, per unit solid angle per unit projected area. This is a directional quantity. This is sometimes also confusingly called "intensity". |
Spectral radiance Specific intensity |
Le,Ω,ν[nb 3] | watt per steradian per square metre per hertz | W⋅sr−1⋅m−2⋅Hz−1 | M⋅T−2 | Radiance of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅sr−1⋅m−2⋅nm−1. This is a directional quantity. This is sometimes also confusingly called "spectral intensity". |
Le,Ω,λ[nb 4] | watt per steradian per square metre, per metre | W⋅sr−1⋅m−3 | M⋅L−1⋅T−3 | ||
Irradiance Flux density |
Ee[nb 2] | watt per square metre | W/m2 | M⋅T−3 | Radiant flux received by a surface per unit area. This is sometimes also confusingly called "intensity". |
Spectral irradiance Spectral flux density |
Ee,ν[nb 3] | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Irradiance of a surface per unit frequency or wavelength. This is sometimes also confusingly called "spectral intensity". Non-SI units of spectral flux density include jansky (1 Jy = 10−26 W⋅m−2⋅Hz−1) and solar flux unit (1 sfu = 10−22 W⋅m−2⋅Hz−1 = 104 Jy). |
Ee,λ[nb 4] | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
Radiosity | Je[nb 2] | watt per square metre | W/m2 | M⋅T−3 | Radiant flux leaving (emitted, reflected and transmitted by) a surface per unit area. This is sometimes also confusingly called "intensity". |
Spectral radiosity | Je,ν[nb 3] | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Radiosity of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅m−2⋅nm−1. This is sometimes also confusingly called "spectral intensity". |
Je,λ[nb 4] | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
Radiant exitance | Me[nb 2] | watt per square metre | W/m2 | M⋅T−3 | Radiant flux emitted by a surface per unit area. This is the emitted component of radiosity. "Radiant emittance" is an old term for this quantity. This is sometimes also confusingly called "intensity". |
Spectral exitance | Me,ν[nb 3] | watt per square metre per hertz | W⋅m−2⋅Hz−1 | M⋅T−2 | Radiant exitance of a surface per unit frequency or wavelength. The latter is commonly measured in W⋅m−2⋅nm−1. "Spectral emittance" is an old term for this quantity. This is sometimes also confusingly called "spectral intensity". |
Me,λ[nb 4] | watt per square metre, per metre | W/m3 | M⋅L−1⋅T−3 | ||
Radiant exposure | He | joule per square metre | J/m2 | M⋅T−2 | Radiant energy received by a surface per unit area, or equivalently irradiance of a surface integrated over time of irradiation. This is sometimes also called "radiant fluence". |
Spectral exposure | He,ν[nb 3] | joule per square metre per hertz | J⋅m−2⋅Hz−1 | M⋅T−1 | Radiant exposure of a surface per unit frequency or wavelength. The latter is commonly measured in J⋅m−2⋅nm−1. This is sometimes also called "spectral fluence". |
He,λ[nb 4] | joule per square metre, per metre | J/m3 | M⋅L−1⋅T−2 | ||
See also: |
- ^ Standards organizations recommend that radiometric quantities should be denoted with suffix "e" (for "energetic") to avoid confusion with photometric or photon quantities.
- ^ a b c d e Alternative symbols sometimes seen: W or E for radiant energy, P or F for radiant flux, I for irradiance, W for radiant exitance.
- ^ a b c d e f g Spectral quantities given per unit frequency are denoted with suffix "ν" (Greek letter nu, not to be confused with a letter "v", indicating a photometric quantity.)
- ^ a b c d e f g Spectral quantities given per unit wavelength are denoted with suffix "λ".
- ^ a b Directional quantities are denoted with suffix "Ω".
Photometry
[edit]
Quantity | Unit | Dimension [nb 1] |
Notes | ||
---|---|---|---|---|---|
Name | Symbol[nb 2] | Name | Symbol | ||
Luminous energy | Qv[nb 3] | lumen second | lm⋅s | T⋅J | The lumen second is sometimes called the talbot. |
Luminous flux, luminous power | Φv[nb 3] | lumen (= candela steradian) | lm (= cd⋅sr) | J | Luminous energy per unit time |
Luminous intensity | Iv | candela (= lumen per steradian) | cd (= lm/sr) | J | Luminous flux per unit solid angle |
Luminance | Lv | candela per square metre | cd/m2 (= lm/(sr⋅m2)) | L−2⋅J | Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit. |
Illuminance | Ev | lux (= lumen per square metre) | lx (= lm/m2) | L−2⋅J | Luminous flux incident on a surface |
Luminous exitance, luminous emittance | Mv | lumen per square metre | lm/m2 | L−2⋅J | Luminous flux emitted from a surface |
Luminous exposure | Hv | lux second | lx⋅s | L−2⋅T⋅J | Time-integrated illuminance |
Luminous energy density | ωv | lumen second per cubic metre | lm⋅s/m3 | L−3⋅T⋅J | |
Luminous efficacy (of radiation) | K | lumen per watt | lm/W | M−1⋅L−2⋅T3⋅J | Ratio of luminous flux to radiant flux |
Luminous efficacy (of a source) | η[nb 3] | lumen per watt | lm/W | M−1⋅L−2⋅T3⋅J | Ratio of luminous flux to power consumption |
Luminous efficiency, luminous coefficient | V | 1 | Luminous efficacy normalized by the maximum possible efficacy | ||
See also: |
- ^ The symbols in this column denote dimensions; "L", "T" and "J" are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
- ^ Standards organizations recommend that photometric quantities be denoted with a subscript "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
- ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.
Other quantities
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
absolute air mass | σ | The integral of air density along the light ray. | scalar | kg m-2 | M L-2 |
back focal distance | s′F′ | The distance from the vertex of the last optical surface of the system to the rear focal point. | scalar | m | L |
circle of confusion | c | An optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. | scalar | m | L |
directional attenuation coefficient | μΩ | Radiance absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
Einstein coefficient A21 | A21 | Coefficient used in calculation of spontaneous emission. | scalar | s-1 | T-1 |
Einstein coefficient B12 | B12 | Coefficient used in calculation of photon absorption. | scalar | m3 J-1 s-2 | M-1 L |
Einstein coefficient B21 | B21 | Coefficient used in calculation of stimulated emission. | scalar | m3 J-1 s-2 | M-1 L |
emission coefficient | ε | A coefficient that describes the emission of atomic line radiation at a certain frequency. | scalar | J s-1 m-3 sr-1 | M L-1 T-3 |
(effective) focal length | f | A measure of how strongly the optical system converges or diverges light. | scalar | m | L |
fringe spacing | df | Separation between maxima in interference of planar waves. | scalar | m | L |
front focal distance | sF | The distance from the front focal point of the system to the vertex of the first optical surface. | scalar | m | L |
front focal length | f | The distance from the front focal point to the front principal plane. | scalar | m | L |
front velocity | vf | The speed at which the first rise of a pulse above zero moves forward. | vector | m s-2 | L T-2 |
group velocity | vg | The velocity with which the overall envelope shape of the wave's amplitudes—known as the modulation or envelope of the wave—propagates through space. | vector | m s-2 | L T-2 |
group velocity dispersion | GVD | The derivative of the inverse of group velocity of light in a material with respect to angular frequency. | vector | m-1 s2 | L-1 T2 |
hemispherical attenuation coefficient | μ | Radiant flux absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
hyperfocal distance | H | A distance from a lens beyond which all objects can be brought into an "acceptable" focus. | scalar | m | L |
image distance | S2 | Distance from a lens to an image produced. | scalar | m | L |
intensity | I | The power carried by light per unit area in a direction perpendicular to that area. | scalar | W m-2 | M T-3 |
longitudinal spherical aberration | LSA | Spherical aberration along the optical axis. | scalar | m | L |
luminosity | L | An absolute measure of radiated electromagnetic energy (light) per unit time, and is synonymous with the radiant power emitted by a light-emitting object. | scalar | W | M L2 T-3 |
object distance | S1 | Distance from a lens to the object. | scalar | m | L |
optical path difference | OPD | Difference of optical path length of two paths. | scalar | m | L |
optical path length | OPL | The length that light needs to travel through a vacuum to create the same phase difference as it would have when traveling through a given medium. | scalar | m | L |
optical power | P | The degree to which a lens, mirror, or other optical system converges or diverges light. | scalar | dpt | L-1 |
phase velocity | vp | The rate at which the wave propagates in any medium. | vector | m s-1 | L T-1 |
rear focal length | f′ | The distance from the rear principal plane to the rear focal point. | scalar | m | L |
recoil energy | Erec | Energy of an atom receiving energy due to the Kapista–Dirac effect. | scalar | J | M L2 T-2 |
recoil frequency | ωrec | Frequency of an atom receiving energy due to the Kapista–Dirac effect. | scalar | Hz | T-1 |
resolvable points distance | r | Distance between two points which can be resolved. | scalar | m | L |
scattering particle size | x | Size of a particle causing scattering. | scalar | m | L |
signal velocity | vs | The speed at which a wave carries information. | vector | m s-1 | L T-1 |
slit width | d | Width of a slit through which light is allowed to pass. | scalar | m | L |
spectral directional attenuation coefficient (per frequency) | μΩ,ν | Spectral radiance absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
spectral directional attenuation coefficient (per wavelength) | μΩ,λ | Spectral radiance absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
spectral energy density | S̄xx | Energy emitted as electromagnetic radiation per frequency. | scalar | J Hz-1 | M L2 T-1 |
spectral energy density (per volume) | u | Energy emitted as electromagnetic radiation per unit volume per frequency. | scalar | J m-3 Hz-1 | M L-1 T-1 |
spectral hemispherical attenuation coefficient (per frequency) | μν | Spectral radiant flux absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
spectral hemispherical attenuation coefficient (per wavelength) | μλ | Spectral radiant flux absorbed and scattered by a volume per unit length, divided by that received by that volume. | scalar | m-1 | L-1 |
spectral power density | Sxx | Energy emitted as electromagnetic radiation per unit time per frequency. | scalar | W Hz-1 | M L2 T-2 |
spectral power density (per volume) | Energy emitted as electromagnetic radiation per unit volume per frequency per unit time. | scalar | W m-3 Hz-1 | M L-1 T-2 | |
spectral power distribution | M | The power per unit area per unit wavelength of an illumination (radiant exitance). | scalar | W m-2 | M T-3 |
speed of light in a material | v | Phase speed of electromagnetic radiation as it passes through a medium. | scalar | m s-1 | L T-1 |
thickness of a lens | d | The distance along the lens axis between the two surface vertices. | scalar | m | L |
transverse spherical aberration | TSA | Spherical aberration perpendicular to the optical axis; the diameter of focus. | scalar | m | L |
wave impedance | Z | The ratio of the transverse components of the electric and magnetic fields. | scalar | Ω | I-2 M L2 T-3 |
Thermodynamics
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
apparent thermal expansion | Apparent thermal expansion of a fluid that is partially due to the expansion of a container. | scalar | m3 | L3 | |
area thermal expansion | ΔA | Change in area due to a change in temperature. | scalar | m2 | L2 |
area thermal expansion coefficient | αA | Area thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
boiling point | Tb | Temperature at which a substance changes from liquid into vapor. | scalar | K | Θ |
boiling point elevation | ΔTb | An increase in the temperature at which a substance boils, caused when a smaller amount of another, non-volatile substance is added. | scalar | K | Θ |
chemical energy | Ec | Energy stored in chemical bonds; chemical potential times the number of particles; used in grand potential calculation. | scalar | J | M L2 T-2 |
chemical potential | μ | The energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition; used in grand potential calculation. | scalar | J | M L2 T-2 |
coefficient of apparent expansion | Apparent expansion of a liquid per unit temperature. | scalar | K-1 | Θ-1 | |
coefficient of linear thermal expansion | αL | Linear thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
compressibility (isentropic) | βS | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isentropic process. | scalar | Pa-1 | M-1 L T2 |
compressibility (isothermal) | βT | A measure of the instantaneous relative volume change of a fluid or solid as a response to a pressure (or mean stress) change in an isothermal process. | scalar | Pa-1 | M-1 L T2 |
configuration entropy / Boltzmann entropy | SB | The portion of a system's entropy that is related to discrete representative positions of its constituent particles. | scalar | J K-1 | Θ-1 M L2 T-2 |
conformational entropy | The entropy associated with the number of conformations of a molecule. | scalar | J K-1 | Θ-1 M L2 T-2 | |
critical point pressure | Pressure where the critical point is situated. | scalar | Pa | M L-1 T-2 | |
critical point temperature | Temperature where the critical point is situated. | scalar | K | Θ | |
cryoscopic constant | Kf | Ratio of freezing point depression to the molality of a solution. | scalar | K kg mol-1 | Θ N-1 M |
ebullioscopic constant | Kc | Ratio of boiling point elevation to the molality of a solution. | scalar | K kg mol-1 | Θ N-1 M |
energy | E | The quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. | scalar | J | M L2 T-2 |
enthalpy | H | Sum of its internal energy and the product of its pressure and volume. | scalar | J | M L2 T-2 |
enthalpy of condensation / heat of condensation (per mass) | qc | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a gas to a liquid. | scalar | J kg-1 | L2 T-2 |
enthalpy of condensation / heat of condensation (per amount) | qc | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a gas to a liquid. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of deposition / heat of deposition (per mass) | qd | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a gas to a solid. | scalar | J kg-1 | L2 T-2 |
enthalpy of deposition / heat of deposition (per amount) | qd | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a gas to a solid. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of fusion / heat of fusion (per mass) | qf | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a solid to a liquid, at constant pressure. | scalar | J kg-1 | L2 T-2 |
enthalpy of fusion / heat of fusion (per amount) | qf | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a solid to a liquid, at constant pressure. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of ionization / heat of ionization (per mass) | qi | The change in its enthalpy resulting from providing energy, to a unit mass of the substance to remove a set number of electrons from each atom/ion. | scalar | J kg-1 | L2 T-2 |
enthalpy of ionization / heat of ionization (per amount) | qi | The change in its enthalpy resulting from providing energy, to a unit amount of the substance to remove a set number of electrons from each atom/ion. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of mixing | ΔHmix | The enthalpy liberated or absorbed from a substance upon mixing. When a substance or compound is combined with any other substance or compound, the enthalpy of mixing is the consequence of the new interactions between the two substances or compounds. | scalar | J | M L2 T-2 |
enthalpy of recombination / heat of recombination (per mass) | qr | The change in its enthalpy resulting from providing energy, to a unit mass of the substance to add a set number of electrons to each atom/ion. | scalar | J kg-1 | L2 T-2 |
enthalpy of recombination / heat of recombination (per amount) | qr | The change in its enthalpy resulting from providing energy, to a unit amount of the substance to add a set number of electrons to each atom/ion. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of solidification / heat of solidification (per mass) | qs | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a liquid to a solid, at constant pressure. | scalar | J kg-1 | L2 T-2 |
enthalpy of solidification / heat of solidification (per amount) | qs | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a liquid to a solid, at constant pressure. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of sublimation / heat of sublimation (per mass) | qs | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a solid to a gas. | scalar | J kg-1 | L2 T-2 |
enthalpy of sublimation / heat of sublimation (per amount) | qs | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a solid to a gas. | scalar | J mol-1 | N M L2 T-2 |
enthalpy of vaporization / heat of vaporization (per mass) | qv | The change in its enthalpy resulting from providing energy, typically heat, to a unit mass of the substance to change its state from a liquid to a gas. | scalar | J kg-1 | L2 T-2 |
enthalpy of vaporization / heat of vaporization (per amount) | qv | The change in its enthalpy resulting from providing energy, typically heat, to a unit amount of the substance to change its state from a liquid to a gas. | scalar | J mol-1 | N M L2 T-2 |
entropic force | F | An emergent phenomenon resulting from the entire system's statistical tendency to increase its entropy, rather than from a particular underlying force on the atomic scale. | vector | N | M L T-2 |
entropy | S | A scientific concept that is most commonly associated with a state of disorder, randomness, or uncertainty. | scalar | J K-1 | Θ-1 M L2 T-2 |
entropy of fusion | Increase in entropy when a solid melts. | scalar | J K-1 | Θ-1 M L2 T-2 | |
entropy of ionization[13] | Increase in entropy during ionization of a gas. | scalar | J K-1 | Θ-1 M L2 T-2 | |
entropy of mixing | Increase in the total entropy of a compound system after mixing. | scalar | J K-1 | Θ-1 M L2 T-2 | |
entropy of vaporization | Increase in entropy during vaporization of a liquid. | scalar | J K-1 | Θ-1 M L2 T-2 | |
free entropy | Either Gibbs free entropy or Helmholtz free entropy. | scalar | J K-1 | Θ-1 M L2 T-2 | |
freezing-point depression | ΔTf | A drop in the maximum temperature at which a substance freezes, caused when a smaller amount of another, non-volatile substance is added. | scalar | K | Θ |
fugacity | f | An effective partial pressure which replaces the mechanical partial pressure in an accurate computation of chemical equilibrium. | scalar | Pa | M L-1 T-2 |
fugacity capacity | Z | Molar concentration divided by fugacity. | scalar | mol m-3 Pa-1 | N M-1 L-2 T2 |
gas constant / difference in heat capacities | k | Pressure energy per unit absolute temperature; equal to amount times molar gas constant. Not to be confused with molar gas constant or specific gas constant. | scalar | J K-1 | Θ-1 M L2 T-2 |
Gibbs free energy | G | A thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure-volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure. | scalar | J | M L2 T-2 |
Gibbs free entropy / Planck potential | Ξ | Negative value of Gibbs free energy divided by temperature. | scalar | J K-1 | Θ-1 M L2 T-2 |
grand potential / Landau free energy | φG or Ω | Helmholtz free energy minus the chemical energy. | scalar | J | M L2 T-2 |
heat | Q | Transfer of energy due to temperature difference. | scalar | J | M L2 T-2 |
heat capacity (isobaric) | Cp | The amount of heat to be supplied to an object to produce a unit change in its temperature in an isobaric process. | scalar | J K-1 | Θ-1 M L2 T-2 |
heat capacity(isochoric) | Cv | The amount of heat to be supplied to an object to produce a unit change in its temperature in an isochoric process. | scalar | J K-1 | Θ-1 M L2 T-2 |
heat current / heat flow / heat transfer | H | Heat transferred per unit time. | scalar | W | M L2 T-3 |
heat flux | φq | A flow of energy per unit area per unit time. | vector | W m-2 | M T-3 |
Helmholtz free energy | F or A | A thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature (isothermal). | scalar | J | M L2 T-2 |
Helmholtz free entropy / Massieu potential | Φ | Negative value of Helmholtz free energy divided by temperature. | |||
internal energy | U | Energy inside a system. | scalar | J | M L2 T-2 |
internal pressure | πT | A measure of how the internal energy of a system changes when it expands or contracts at constant temperature. | scalar | Pa | M L-1 T-2 |
latent heat | Ql | Energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. | scalar | J | M L2 T-2 |
latent internal energy | Ul | The internal energy a system requires to undergo a phase transition. | scalar | J | M L2 T-2 |
lattice energy | ΔElattice | The energy change upon formation of one mole of a crystalline ionic compound from its constituent ions, which are assumed to initially be in the gaseous state. | scalar | J | M L2 T-2 |
lattice enthalpy | ΔHlattice | The enthalpy change upon formation of one mole of a crystalline ionic compound from its constituent ions, which are assumed to initially be in the gaseous state. | scalar | J | M L2 T-2 |
linear thermal expansion | Δd | Change in length due to a change in temperature. | scalar | m | L |
loop entropy | The entropy lost upon bringing together two residues of a polymer within a prescribed distance. | scalar | J K-1 | Θ-1 M L2 T-2 | |
melting point | Tm | Temperature at which a substance changes from solid into liquid. | scalar | K | Θ |
molar energy | em | Energy pr unit amount. | scalar | J mol-1 | N M L2 T-2 |
molar enthalpy | Hm | Enthalpy per unit amount. | scalar | J mol-1 | N M L2 T-2 |
molar Gibbs free energy | gm | Gibbs free energy per unit amount. | scalar | J mol-1 | N M L2 T-2 |
molar heat capacity (isobaric) | cp,m | The amount of heat to be supplied to a unit amount of an object to produce a unit change in its temperature in an isobaric process. | scalar | J mol-1 K-1 | N-1 Θ-1 M L2 T-2 |
molar heat capacity (isochoric) | cv,m | The amount of heat to be supplied to a unit amount of an object to produce a unit change in its temperature in an isochoric process. Equals to isobaric heat capacity minus the molar gas constant. | scalar | J mol-1 K-1 | N-1 Θ-1 M L2 T-2 |
molar internal energy | Internal energy per unit amount. | scalar | J mol-1 | N M L2 T-2 | |
molar latent heat | Latent heat per unit amount. | scalar | J mol-1 | N M L2 T-2 | |
molar latent internal energy | Latent internal energy per unit amount. | scalar | J mol-1 | N M L2 T-2 | |
molar volume | Vm | Volume occupied by a unit amount. Used for calculating the thermal expansion of gases. | scalar | m3 mol-1 | N-1 L3 |
phase transition pressure | Pressure where the phase change occurs. | scalar | Pa | M L-1 T-2 | |
phase transition temperature | Temperature where the phase change occurs. | scalar | K | Θ | |
pressure energy | Ɛp | Product of pressure and volume. | scalar | J | M L2 T-2 |
Redlich–Kwong coefficient a | a | A parameter used in Redlich–Kwong equation. | scalar | Pa K½ m6 mol-2 | N-2 Θ½ M L5 T-2 |
Redlich–Kwong coefficient b | b | A parameter used in Redlich–Kwong equation. | scalar | m3 mol-1 | N-1 L3 |
specific energy | e | Energy per unit mass of a fuel. | scalar | J kg-1 | L2 T-2 |
specific enthalpy | h | Enthalpy per unit mass. | scalar | J kg-1 | L2 T-2 |
specific entropy | s | Entropy per unit mass. | scalar | J kg-1 K-1 | Θ-1 L2 T-2 |
specific gas constant | Rspecific | The molar gas constant divided by the molar mass of a gas; the difference between both specific heat capacities. | scalar | J kg-1 K-1 | Θ-1 L2 T-2 |
specific Gibbs free energy | g | Gibbs free energy per unit mass. | scalar | J kg-1 | L2 T-2 |
specific heat capacity (isobaric) | cp | The amount of heat to be supplied to a unit mass of an object to produce a unit change in its temperature in an isobaric process. | scalar | J kg-1 K-1 | Θ-1 L2 T-2 |
specific heat capacity (isochoric) | cv | The amount of heat to be supplied to a unit mass of an object to produce a unit change in its temperature in an isochoric process. | scalar | J kg-1 K-1 | Θ-1 L2 T-2 |
specific internal energy | Internal energy per unit mass. | scalar | J kg-1 | L2 T-2 | |
specific latent heat | L | Latent heat per unit mass. | scalar | J kg-1 | L2 T-2 |
specific latent internal energy | Latent internal energy per unit mass. | scalar | J kg-1 | L2 T-2 | |
specific power | PWR | Power delivered by unit mass. | scalar | W kg-1 | L2 T-3 |
sublimation temperature | Ts | Temperature at which a substance changes from solid into vapor. | scalar | K | Θ |
temperature | T | One of the base physical quanttities. | scalar | K | Θ |
thermal admittance / heat transfer coefficient / U-value | h | The proportionality constant between the heat flux and the thermodynamic driving force for the flow of heat. | scalar | W m-2 K-1 | Θ-1 M T-3 |
thermal conductance | C | The ability of materials or systems to conduct heat and the opposition they offer to the heat current. | scalar | W K-1 | Θ-1 M L2 T-3 |
thermal conductivity | κ | A measure of material's ability to conduct heat. | scalar | W m-1 K-1 | Θ-1 M L T-3 |
thermal diffusivity | α | A measure of heat transfer inside a material. | scalar | m2 s-1 | L2 T-1 |
thermal energy | Et | Energy that is measured by temperature. | scalar | J | M L2 T-2 |
thermal insulance / R-value | Rval | A measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat. | scalar | m2 K W-1 | Θ M-1 T3 |
thermal resistance | R | The ability of materials or systems to conduct heat and the opposition they offer to the heat current. | scalar | K W-1 | Θ M-1 L-2 T3 |
thermal resistivity | ρ | The inverse of thermal conductivity; a material's resistance to conduct heat. | scalar | K m W-1 | Θ M-1 L-1 T3 |
thermodynamic potential | Can refer to either internal energy, Helmholtz free energy, enthalpy, Gibbs free energy, or grand potential. | scalar | J | M L2 T-2 | |
thermodynamic work | Wt | Work done by a thermodynamic system. | scalar | J | M L2 T-2 |
triple point pressure | Pressure where the triple point is situated. | scalar | Pa | M L-1 T-2 | |
triple point temperature | Temperature where the triple point is situated. | scalar | K | Θ | |
Van der Waals parameter a | a | A parameter used in Van der Waals equation. | scalar | Pa m6 mol-2 | N-2 M L5 T-2 |
Van der Waals parameter b | b | A parameter used in Van der Waals equation. | scalar | m3 mol-1 | N-1 L3 |
vapor pressure | The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. | scalar | Pa | M L-1 T-2 | |
volumetric thermal expansion | ΔV | Change in volume due to a change in temperature. | scalar | m3 | L3 |
volumetric thermal expansion coefficient | αV | Volumetric thermal expansion per unit temperature. | scalar | K-1 | Θ-1 |
work | W | Energy transferred to an object or from it. | scalar | J | M L2 T-2 |
Electromagnetism
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
admittance | Y | A measure of how easily a circuit or device will allow a current to flow. | scalar | A | I |
amplitude (of electric current) | A measure of its change in a single period in AC current. | scalar | A | I | |
amplitude (of magnetic flux) | A measure of its change in a single period produced by or producing AC current. | vector | Wb | I-1 M L2 T−2 | |
amplitude (of magnetomotive force) | A measure of its change in a single period produced by or producing AC current. | vector | A | I | |
amplitude (of voltage) | A measure of its change in a single period in AC current. | scalar | V | I-1 M L2 T−3 | |
capacitive reactance | XC | Reactance due to the capacitance. | scalar | Ω | I-2 M L2 T-3 |
electric current (intensity) | I | One of the base quantities. | scalar | A | I |
electric field work | We | Work done by the electric field. | scalar | J | M L2 T-2 |
electric force | Fe | Force due to the electric field. | vector | N | M L T-2 |
electric potential energy | Ee | Energy gained due to electric field work. | scalar | J | M L2 T-2 |
electrical admittance | Y | A measure of how easily a circuit or device will allow a current to flow. | scalar | S | I2 M-1 L-2 T3 |
electrical conductance | G | The inverse of electrical resistance. | scalar | S | I2 M-1 L-2 T3 |
electrical conductivity | σ | The inverse of electrical resistivity. | scalar | S m-1 | I2 M-1 L-3 T3 |
electrical impedance | Z | The inverse of electrical admittance. | scalar | Ω | I-2 M L2 T-3 |
electrical reactance | X | The opposition presented to alternating current by inductance and capacitance. | scalar | Ω | I-2 M L2 T-3 |
electrical resistance | R | A measure of an object's opposition to the flow of electric current. | scalar | Ω | I-2 M L2 T-3 |
electrical resistivity | ρ | A measure of a matterial's opposition to the flow of electric current. | scalar | Ω m | I-2 M L3 T-3 |
electrical susceptance | B | The inverse of electrical reactance. | scalar | S | I2 M-1 L-2 T3 |
inductive reactance | XL | Reactance due to inductance. | scalar | Ω | I-2 M L2 T-3 |
Lorentz force / electromagnetic force | Fl | Force due to the electromagnetic field. | vector | N | M L T-2 |
magnetic field work | Wm | Work done by the magnetic field. | scalar | J | M L2 T-2 |
magnetic force | Fm | Force due to the magnetic field. | vector | N | M L T-2 |
magnetic potential energy | Em | Energy gained due to the magnetic field work. | scalar | J | M L2 T-2 |
peak amplitude (of electric current) | Ipeak | The maximum absolute value of current in AC current. | scalar | A | I |
peak amplitude (of magnetic flux) | φpeak | The maximum absolute value of magnetic flux produced by or producing AC current. | vector | Wb | I-1 M L2 T−2 |
peak amplitude (of magnetomotive force) | peak | The maximum absolute value of magnetomotive force produced by or producing AC current. | vector | A | I |
peak amplitude (of voltage) | Vpeak | The maximum absolute value of voltage in AC current. | scalar | V | I-1 M L2 T−3 |
peak-to-peak amplitude (of electric current) | Twice the maximum absolute value of current in AC current. | scalar | A | I | |
peak-to-peak amplitude (of magnetic flux) | Twice the maximum absolute value of magnetic flux produced by or producing AC current. | vector | Wb | I-1 M L2 T−2 | |
peak-to-peak amplitude (of magnetomotive force) | Twice the maximum absolute value of magnetomotive force produced by or producing AC current. | vector | A | I | |
peak-to-peak amplitude (of voltage) | Twice the maximum absolute value of voltage in AC current. | scalar | V | I-1 M L2 T−3 | |
root mean square amplitude (of electric current) | Twice the maximum absolute value of current in AC current. | scalar | A | I | |
root mean square amplitude (of magnetic flux) | Twice the maximum absolute value of magnetic flux produced by or producing AC current. | vector | Wb | I-1 M L2 T−2 | |
root mean square amplitude (of magnetomotive force) | Twice the maximum absolute value of magnetomotive force produced by or producing AC current. | vector | A | I | |
root mean square amplitude (of voltage) | Twice the maximum absolute value of voltage in AC current. | scalar | V | I-1 M L2 T−3 | |
voltage | V | Difference in electric potential between two points in space. | scalar | V | I-1 M L2 T−3 |
Astrophysics and cosmology
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
anomalistic period | The time that elapses between two passages of an object at its periapsis. | scalar | s | T | |
Coriolis frequency | f | Frequency of inertial oscillation resulting from Coriolis effect. | scalar | Hz | T-1 |
gravitational field strength | g | Weight experienced by one unit of mass. Magnitude of gravity. | scalar | N kg-1 | L T-2 |
gravitational field work | Wg | Work done by the gravitational field. | scalar | J | M L2 T-2 |
gravitational force | Fg | Force due to the gravitational attraction. | vector | N | M L T-2 |
gravitational potential | Vg | Gravitational potential energy per unit mass of an object. | scalar | J kg-1 | L2 T-2 |
gravitational potential energy | Eg | Energy gained due to the gravitational field work. | scalar | J | M L2 T-2 |
gravity | g | Acceleration due to weight. | vector | m s-2 | L T-2 |
nodal period / draconic period | Tn | The time that elapses between two passages of the object through its ascending node, the point of its orbit where it crosses the ecliptic from the southern to the northern hemisphere. | scalar | s | T |
orbital period / revolution period | T | The amount of time a given astronomical object takes to complete one orbit around another object. | scalar | s | T |
sidereal period | Tsid | A 360° revolution of one body around its primary relative to the fixed stars projected in the sky | scalar | s | T |
sidereal rotation period | The time that the object takes to complete a full rotation around its axis relative to the background stars. | pseudoscalar | s | T | |
synodic period | Tsyn | The amount of time that it takes for an object to reappear at the same point in relation to two or more other objects. | scalar | s | T |
synodic rotation period | The period for a celestial object to rotate once in relation to the star it is orbiting. | pseudoscalar | s | T | |
tropical period | The interval between two alignments of its rotational axis with the Sun, also viewed as two passages of the object at a right ascension of 0 hr. | scalar | s | T | |
rotation period | T | The time that the object takes to complete a full rotation about its axis. | scalar | s | T |
specific weight | γ (scalar)
γ (vector) |
Density times gravitational field strength (scalar) or weight per unit volume (vector). | scalar or vector | N m-3 | M L-2 T-2 |
weight | W (vector)
W (scalar) |
Force due to the gravitational attraction (vector) or its magnitude (scalar). Usually used for objects with negligible effect on gravitational field. See also gravitational force. | vector or scalar | N | M L T-2 |
Atomic, nuclear and particle physics
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
absorbed dose | D | The energy deposited in matter by ionizing radiation per unit mass. | scalar | Gy | L2 T-2 |
absorbed dose rate | Ḋ | Rate of absorbing ionizing radiation per unit mass. | scalar | Gy s-1 | L2 T-3 |
activity | A | The number of radioactive transformations per second that occur in a particular radionuclide. | scalar | Bq | T-1 |
chemical energy | Ec | Energy stored in chemical bonds. | scalar | J | M L2 T-2 |
chromodynamic energy | Energy binding quarks in a hadron. | scalar | J | M L2 T-2 | |
decay constant | λ | Reciprocal of mean lifetime. | scalar | s-1 | T-1 |
energy | E | The quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. | scalar | J | M L2 T-2 |
half-life | t½ | Time taken for half of the radioactive particles to decay. | scalar | s | T |
kerma | K | Kinetic energy released per unit mass. | scalar | Gy | L2 T-2 |
mean lifetime | τ | Average lifetime of a radioactive particle. | scalar | s | T |
nuclear binding energy | En | Energy required to separate particles in a nucleus. | scalar | J | M L2 T-2 |
nuclear force | Fn | Force due to strong interaction. | usually scalar | N | M L T-2 |
rest energy | Energy due to the object's rest mass. | scalar | J | M L2 T-2 | |
specific activity | a | Activity of a radioactive substance per unit mass. | scalar | Bq kg-1 | M-1 T-1 |
Chemistry
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
activation energy | Ea | Energy needed for a reaction to occur. | scalar | J | M L2 T-2 |
chemical energy | Ec | Energy stored in chemical bonds. | scalar | J | M L2 T-2 |
energy | E | The quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. | scalar | J | M L2 T-2 |
enthalpy | H | Sum of its internal energy and the product of its pressure and volume. | scalar | J | M L2 T-2 |
enthalpy of reaction | ΔHreaction | Change of enthalpy during a reaction. | scalar | J | M L2 T-2 |
incipient lethal level | LC50 | Lethal concentration of a substance, independent of time. | scalar | kg m-3 | M L-3 |
internal energy | U | Energy inside a system. | scalar | J | M L2 T-2 |
ionization energy (per electron) | IE | Energy needed to remove an electron from an atom, ion or molecule. | scalar | J | M L2 T-2 |
lowest lethal concentration | LCLo | The lowest concentration of a chemical, given over a period of time, that results in the fatality of an individual animal. LCLo is typically for an acute (<24 hour) exposure. | scalar | kg m-3 | M L-3 |
median lethal concentration | LCt50 | A measure of how toxic a substance is when inhaled or spilled on body tissue. | scalar | kg s m-3 | M L-3 T |
standard enthalpy of reaction | The difference between total product and total reactant molar enthalpies, calculated for substances in their standard states. | scalar | J | M L2 T-2 | |
vapor concentration (by mass) | C*[14] | Concentration of vapor of a substance in the air. | scalar | kg m-3 | M L-3 |
vapor pressure | The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. | scalar | Pa | M L-1 T-2 | |
work | W | Energy transferred to an object or from it. | scalar | J | M L2 T-2 |
Biology, medicine & sports
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
ambient dose equivalent | H*(d) | scalar | Sv | L2 T-2 | |
acceleration density[15] | Acceleration load per unit time. | scalar | m s-3 | L T-3 | |
acceleration density index[15] | Acceleration load per distance moved. | scalar | s-3 | T-3 | |
acceleration load[15] | Magnitude of acceleration during activity. | scalar | m s-2 | L T-2 | |
directional dose equivalent | H' (d, Ω) | scalar | Sv | L2 T-2 | |
effective dose | E | The tissue-weighted sum of the equivalent doses in all specified tissues and organs of the human body and represents the stochastic health risk to the whole body, which is the probability of cancer induction and genetic effects, of low levels of ionizing radiation. | scalar | Sv | L2 T-2 |
energy | E | The quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. | scalar | J | M L2 T-2 |
energy density | we | Energy per unit volume (of food). | scalar | J m-3 | M L-1 T-2 |
equivalent dose | H | It is derived from the physical quantity absorbed dose, but also takes into account the biological effectiveness of the radiation, which is dependent on the radiation type and energy. | scalar | Sv | L2 T-2 |
heating value / calorific value (per amount) | Energy released per mole. | scalar | J mol-1 | M L2 T-2 N-1 | |
heating value / calorific value (per mass) | Energy released per unit mass. | scalar | J kg-1 | M2 T2 | |
heating value / calorific value (per volume) | Energy released per unit volume. | scalar | J m-3 | M L-1 T-2 | |
infective dosage | ICt50 | The number of infective doses per minute for a cubic meter. | scalar | s m-3 | L-3 T |
organ absorbed dose | DT | The energy deposited in matter by ionizing radiation per unit mass of an organ. | scalar | Gy | L2 T-2 |
organ equivalent dose | HT | Equivalent dose received by an organ. | scalar | Sv | L2 T-2 |
personal dose equivalent | Hp | scalar | Sv | L2 T-2 | |
specific energy | e | Energy per unit mass of food. | scalar | J kg-1 | L2 T-2 |
specific power | PWR | Power delivered by unit mass. | scalar | W kg-1 | L2 T-3 |
Energy production and consumption
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
chemical energy | Ec | Energy stored in a fuel, released when burned. | scalar | J | M L2 T-2 |
emissions per energy produced | Mass of emissions per unit of energy produced from fuel. | scalar | kg J-1 | L-2 T2 | |
energy | E | The quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. | scalar | J | M L2 T-2 |
energy density | we | Energy per unit volume (of a fuel). | scalar | J m-3 | M L-1 T-2 |
energy efficiency (per fuel volume) | Reciprocal of fuel efficiency. | scalar | m m-3 | L-2 | |
fuel consumption (per fuel mass) | Mass of fuel consumed per time unit. | scalar | kg s-1 | M T-1 | |
fuel consumption (per fuel volume) | Volume of fuel consumed per time unit. | scalar | m3 s-1 | L3 T-1 | |
fuel efficiency / fuel economy (per fuel mass) | Measure of the fuel used to traverse a set distance. | scalar | kg m-1 | M L-1 | |
fuel efficiency / fuel economy (per fuel volume) | Measure of the fuel used to traverse a set distance. (usually in L/100 km) | scalar | m3 m-1 | L2 | |
heating value / calorific value (per amount) | Energy released per mole. | scalar | J mol-1 | M L2 T-2 N-1 | |
heating value / calorific value (per mass) | Energy released per unit mass. | scalar | J kg-1 | M2 T2 | |
heating value / calorific value (per volume) | Energy released per unit volume. | scalar | J m-3 | M L-1 T-2 | |
power density | Pd | Power per unit volume. | scalar | W m-3 | M L-1 T-3 |
ramping rate[16] | Rate of power production during powering up and down of power stations. | scalar | W s-1 | M L2 T-4 | |
specific energy | e | Energy per unit mass of a fuel. | scalar | J kg-1 | L2 T-2 |
specific enthalpy | h | Enthalpy per unit mass | scalar | J kg-1 | L2 T-2 |
specific power | PWR | Power delivered by unit mass. | scalar | W kg-1 | L2 T-3 |
surface energy density | Energy per unit area. | scalar | J m-2 | M T-2 | |
surface power density | Pd | Power per unit area. | scalar | W m-2 | M T-3 |
Geography
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
Coriolis frequency | f | Frequency of inertial oscillation resulting from Coriolis effect. | scalar | Hz | T-1 |
Gauckler–Manning coefficient | n | A coefficient in Manning formula. | scalar | s m-⅓ | L-⅓ T |
volumetric flow acceleration | V̈ | Acceleration of volumetric flow rate. | scalar | m3 s-2 | L3 T-2 |
volumetric flow rate / discharge | Q | Rate of flow in regard to volume. | scalar | m3 s-1 | L3 T-1 |
Transportation
[edit]Quantity | Symbol | Description | Vector/scalar | SI unit | Dimension |
---|---|---|---|---|---|
emissions per payload-distance | Mass of emissions per movement of freight. | scalar | kg kg-1 m-1 | L-1 | |
energy efficiency (per fuel volume) | Reciprocal of fuel efficiency. | scalar | m m-3 | L-2 | |
energy per freight moved | Energy consumed for freight movement for a unit distance. | scalar | J kg-1 m-1 | L T-2 | |
fuel efficiency / fuel economy (per unit mass) | Measure of the fuel used to traverse a set distance. | scalar | kg m-1 | M L-1 | |
fuel efficiency / fuel economy (per fuel volume) | Measure of the fuel used to traverse a set distance. (usually in L/100 km) | scalar | m3 m-1 | L2 | |
payload-distance | Mass of freight moved by a set distance. | scalar | kg m | M L |
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