Physics Derived Quantities

Derived quantitySymbolComments
Plane angleθMeasure of a change in direction or orientation.radian (rad)1
Solid angleΩMeasure of the size of an object as projected on a sphere.steradian (sr)1
Absorbed dose rateAbsorbed dose received per unit of time.Gy s−1L2 T−3
AccelerationaRate of change of the speed or velocity of an object.m s−2L T−2vector
Angular accelerationαRate of change in angular speed or velocity.rad s−2T−2
Angular speed (or angular velocity)ωThe angle incremented in a plane by a segment connecting an object and a reference point.rad s−1T−1scalar or pseudovector
Angular momentumLMeasure of the extent and direction and object rotates about a reference m2 s−1M L2 T−1conserved quantity, pseudovector
AreaAThe two-dimensional extent of an object.m2L2
Area densityρAThe amount of mass per unit area of a two-dimensional m−2M L−2
CapacitanceCMeasure for the amount of stored charge for a given potential.farad (F = A2 s4 kg−1m−2)I2 T4 M−1 L−2
Catalytic activityChange in reaction rate due to presence of a catalyst.katal (kat = mol s−1)N T−1
Catalytic activity concentrationChange in reaction rate due to presence of a catalyst per unit volume of the system.kat m−3N L−3 T−1
Chemical potentialμThe amount of energy needed to add a particle to a system.J mol−1M L2 T−2 N−1intensive
Molar concentrationCAmount of substance per unit volume.mol m−3N L−3intensive
Current densityJ Amount of electric current flowing through a surface.A m−2I L−2vector
Dose equivalentHMeasure for the received amount of radiation adjusted for the effect of different types of radiant on biological tissue.sievert (Sv = m2 s−2)L2 T−2
Dynamic ViscosityηMeasure for the resistance of an incompressible fluid to stress.Pa sM L−1 T−1
Electric ChargeQAmount of electric charge.coulomb (C = A s)I Textensive, conserved quantity
Electric charge densityρQAmount of electric charge per unit volume.C m−3I T L−3intensive
Electric displacementDStrength of the electric displacement.C m−2I T L−2vector field
Electric field strengthEStrength of the electric field.V m−1M L T−3 I−1vector field
Electrical conductanceGMeausure for how easily current flows through a material.siemens (S = A2 s3 kg−1 m−2)L−2 M−1 T3 I2scalar
Electric potentialVThe amount of work required to bring a unit charge into an electric field from infinity.volt (V = kg m2 A−1 s−3)L2 M T−3 I−1scalar
Electrical resistanceRThe degree to which an object opposes the passage of an electric current.ohm (Ω = kg m2 A−2 s−3)L2 M T−3 I−2scalar
EnergyEThe capacity of a body or system to do work.joule (J = kg m2 s−2)M L2 T−2extensive, scalar, conserved quantity
Energy densityρEAmount of energy per unit volume.J m−3M L−1 T−2intensive
EntropySMeasure for the amount of available states for a system.J K−1M L2 T−2 Θ−1extensive, scalar
ForceFThe cause of acceleration, acting on an object.newton (N = kg m s−2)M L T−2vector
ImpulsepThe cause of a change in momentum, acting on an m s−1M L T−1vector
FrequencyfThe number of times something happens in a period of time.hertz (Hz =s−1)T−1
Half-lifet1/2The time needed for a quantity to decay to half its original value.sT
HeatQAmount of energy transferred between systems due to temperature difference.JM L2 T−2
Heat capacityCpAmount of energy needed to raise the temperature of a system by one degree.J K−1M L2 T−2 Θ−1extensive
Heat flux densityϕQAmount of heat flowing through a surface per unit area.W m−2M T−3
IlluminanceEvTotal luminous flux incident to a surface per unit area.lux (lx = cd sr m−2)J L−2
ImpedanceZMeasure for the resistance of an electrical circuit against an alternating current.ohm (Ω = kg m2 A−2 s−3)L2 M T−3 I−2complex scalar
Index of refractionnThe factor by which the speed of light is reduce in a medium.1intensive
InductanceLMeasure for the amount of magnetic flux generated for a certain current run through a circuit.henry (H = kg m2 A−2 s−2)M L2 T−2 I−2
IrradianceEPower of electromagnetic radiation flowing through a surface per unit area.W m−2M T−2
Linear densityρlAmount of mass per unit length of a one-dimensional object.M L−1
Luminous flux (orluminous power)FPerceived power of a light source.lumen (lm = cd sr)J
Magnetic field strengthHStrength of a magnetic field in a material.A m−1I L−1vector field
Magnetic fluxΦMeasure of quantity of magnetism, taking account of the strength and the extent of a magnetic (Wb = kg m2 A−1 s−2)M L2 T−2 I−1scalar
Magnetic flux densityBMeasure for the strength of the magnetic field.tesla (T = kg A−1 s−2)M T−2 I−1pseudovector field
MagnetizationMAmount of magnetic moment per unit volume.A m−1I L−1vector field
Mass fractionxMass of a substance as a fraction of the total
(Mass) Density (volume density)ρThe amount of mass per unit volume of a three-dimensional m−3M L−3intensive
Mean lifetimeτAverage time needed for a particle to decay.sTintensive
Molar energyAmount of energy present is a system per unit amount of substance.J mol−1M L2 T−2 N−1intensive
Molar entropyAmount of entropy present in a system per unit amount of substance.J K−1 mol−1M L2 T−2 Θ−1 N−1intensive
Molar heat capacitycHeat capacity of a material per unit amount of substance.J K−1 mol−1M L2 T−2 N−1intensive
Moment of inertiaIInertia of an object with respect to angular m2M L2tensor
MomentumpProduct of an object's mass and velocity.N sM L T−1vector, extensive
PermeabilityμMeasure for how the magnetization of material is affected by the application of an external magnetic field.H m−1M L−1 I−2intensive
PermittivityεMeasure for how the polarization of a material is affected by the application of an external electric field.F m−1I2 M−1 L−3 T4intensive
PowerPThe rate of change in energy over time.watt (W)M L2 T−3extensive
PressurepAmount of force per unit area.pascal (Pa = kg m−1 s−2)M L−1 T−2intensive
(Radioactive) ActivityANumber of particles decaying per unit time.becquerel (Bq = s−1)T−1extensive
(Radioactive) DoseDAmount of energy absorbed by biological tissue from ionizing radiation per unit mass.gray (unit) (Gy = m2 s−2)L2 T−2
RadianceLPower of emitted electromagnetic radiation per solid angle and per projected source area.W m−2 sr−1M T−3
Radiant intensityIPower of emitted electromagnetic radiation per solid angle.W sr−1M L2 T−3scalar
Reaction raterMeasure for speed of a chemical reaction.mol m−3 s−1N L−3 T−1intensive
SpeedvRate of change of the position of an object.m s−1L T−1scalar
Specific energyAmount of energy present per unit mass.J kg−1L2 T−2intensive
Specific heat capacitycHeat capacity per unit mass.J kg−1 K−1L2 T−2 Θ−1intensive
Specific volumevThe volume occupied by a unit mass of material (reciprocal of density).m3 kg−1L3 M−1intensive
SpinSIntrinsic property of particles, roughly to be interpreted as the intrinsic angular momentum of the m2 s−1M L2 T−1
StressσAmount of force exerted per surface area.PaM L−1 T−22-tensor. (or scalar)
Surface tensionγAmount of work needed to change the surface of a liquid by a unit surface area.N m−1 or J m−2M T−2
Thermal conductivitykMeasure for the ease with which a material conducts heat.W m−1 K−1M L T−3 Θ−1intensive
TorqueτProduct of a force and the perpendicular distance of the force from the point about which it is exerted.N mM L2 T−2pseudovector
VelocityvSpeed of an object in a chosen direction.m s−1L T−1vector
VolumeVThe three dimensional extent of an object.m3L3extensive
WavelengthλDistance between repeating units of a propagating wave.mL
WavenumberkReciprocal of the wavelength.m−1L−1
WeightwAmount of gravitation force exerted on an object.newton (N = kg m s−2)M L T−2
WorkWEnergy dissipated by a force moving over a distance, scalar product of the force and the movement vector.joule (J = kg m2 s−2)M L2 T−2scalar

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