Physics Derived Quantities

Derived quantity	Symbol	Comments
Plane angle	θ	Measure of a change in direction or orientation.	radian (rad)	1
Solid angle	Ω	Measure of the size of an object as projected on a sphere.	steradian (sr)	1
Absorbed dose rate		Absorbed dose received per unit of time.	Gy s−1	L2 T−3
Acceleration	a→	Rate of change of the speed or velocity of an object.	m s−2	L T−2	vector
Angular acceleration	α	Rate of change in angular speed or velocity.	rad s−2	T−2
Angular speed (or angular velocity)	ω	The angle incremented in a plane by a segment connecting an object and a reference point.	rad s−1	T−1	scalar or pseudovector
Angular momentum	L	Measure of the extent and direction and object rotates about a reference point.	kg m2 s−1	M L2 T−1	conserved quantity, pseudovector
Area	A	The two-dimensional extent of an object.	m2	L2
Area density	ρA	The amount of mass per unit area of a two-dimensional object.	kg m−2	M L−2
Capacitance	C	Measure for the amount of stored charge for a given potential.	farad (F = A2 s4 kg−1m−2)	I2 T4 M−1 L−2
Catalytic activity		Change in reaction rate due to presence of a catalyst.	katal (kat = mol s−1)	N T−1
Catalytic activity concentration		Change in reaction rate due to presence of a catalyst per unit volume of the system.	kat m−3	N L−3 T−1
Chemical potential	μ	The amount of energy needed to add a particle to a system.	J mol−1	M L2 T−2 N−1	intensive
Molar concentration	C	Amount of substance per unit volume.	mol m−3	N L−3	intensive
Current density	J →	Amount of electric current flowing through a surface.	A m−2	I L−2	vector
Dose equivalent	H	Measure 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 Viscosity	η	Measure for the resistance of an incompressible fluid to stress.	Pa s	M L−1 T−1
Electric Charge	Q	Amount of electric charge.	coulomb (C = A s)	I T	extensive, conserved quantity
Electric charge density	ρQ	Amount of electric charge per unit volume.	C m−3	I T L−3	intensive
Electric displacement	D	Strength of the electric displacement.	C m−2	I T L−2	vector field
Electric field strength	E→	Strength of the electric field.	V m−1	M L T−3 I−1	vector field
Electrical conductance	G	Meausure for how easily current flows through a material.	siemens (S = A2 s3 kg−1 m−2)	L−2 M−1 T3 I2	scalar
Electric potential	V	The 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−1	scalar
Electrical resistance	R	The 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−2	scalar
Energy	E	The capacity of a body or system to do work.	joule (J = kg m2 s−2)	M L2 T−2	extensive, scalar, conserved quantity
Energy density	ρE	Amount of energy per unit volume.	J m−3	M L−1 T−2	intensive
Entropy	S	Measure for the amount of available states for a system.	J K−1	M L2 T−2 Θ−1	extensive, scalar
Force	F→	The cause of acceleration, acting on an object.	newton (N = kg m s−2)	M L T−2	vector
Impulse	p→	The cause of a change in momentum, acting on an object.	kg m s−1	M L T−1	vector
Frequency	f	The number of times something happens in a period of time.	hertz (Hz =s−1)	T−1
Half-life	t1/2	The time needed for a quantity to decay to half its original value.	s	T
Heat	Q	Amount of energy transferred between systems due to temperature difference.	J	M L2 T−2
Heat capacity	Cp	Amount of energy needed to raise the temperature of a system by one degree.	J K−1	M L2 T−2 Θ−1	extensive
Heat flux density	ϕQ	Amount of heat flowing through a surface per unit area.	W m−2	M T−3
Illuminance	Ev	Total luminous flux incident to a surface per unit area.	lux (lx = cd sr m−2)	J L−2
Impedance	Z	Measure for the resistance of an electrical circuit against an alternating current.	ohm (Ω = kg m2 A−2 s−3)	L2 M T−3 I−2	complex scalar
Index of refraction	n	The factor by which the speed of light is reduce in a medium.		1	intensive
Inductance	L	Measure 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
Irradiance	E	Power of electromagnetic radiation flowing through a surface per unit area.	W m−2	M T−2
Linear density	ρl	Amount of mass per unit length of a one-dimensional object.		M L−1
Luminous flux (orluminous power)	F	Perceived power of a light source.	lumen (lm = cd sr)	J
Magnetic field strength	H	Strength of a magnetic field in a material.	A m−1	I L−1	vector field
Magnetic flux	Φ	Measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field.	weber (Wb = kg m2 A−1 s−2)	M L2 T−2 I−1	scalar
Magnetic flux density	B	Measure for the strength of the magnetic field.	tesla (T = kg A−1 s−2)	M T−2 I−1	pseudovector field
Magnetization	M	Amount of magnetic moment per unit volume.	A m−1	I L−1	vector field
Mass fraction	x	Mass of a substance as a fraction of the total mass.	kg/kg	1	intensive
(Mass) Density (volume density)	ρ	The amount of mass per unit volume of a three-dimensional object.	kg m−3	M L−3	intensive
Mean lifetime	τ	Average time needed for a particle to decay.	s	T	intensive
Molar energy		Amount of energy present is a system per unit amount of substance.	J mol−1	M L2 T−2 N−1	intensive
Molar entropy		Amount of entropy present in a system per unit amount of substance.	J K−1 mol−1	M L2 T−2 Θ−1 N−1	intensive
Molar heat capacity	c	Heat capacity of a material per unit amount of substance.	J K−1 mol−1	M L2 T−2 N−1	intensive
Moment of inertia	I	Inertia of an object with respect to angular acceleration.	kg m2	M L2	tensor
Momentum	p→	Product of an object's mass and velocity.	N s	M L T−1	vector, extensive
Permeability	μ	Measure for how the magnetization of material is affected by the application of an external magnetic field.	H m−1	M L−1 I−2	intensive
Permittivity	ε	Measure for how the polarization of a material is affected by the application of an external electric field.	F m−1	I2 M−1 L−3 T4	intensive
Power	P	The rate of change in energy over time.	watt (W)	M L2 T−3	extensive
Pressure	p	Amount of force per unit area.	pascal (Pa = kg m−1 s−2)	M L−1 T−2	intensive
(Radioactive) Activity	A	Number of particles decaying per unit time.	becquerel (Bq = s−1)	T−1	extensive
(Radioactive) Dose	D	Amount of energy absorbed by biological tissue from ionizing radiation per unit mass.	gray (unit) (Gy = m2 s−2)	L2 T−2
Radiance	L	Power of emitted electromagnetic radiation per solid angle and per projected source area.	W m−2 sr−1	M T−3
Radiant intensity	I	Power of emitted electromagnetic radiation per solid angle.	W sr−1	M L2 T−3	scalar
Reaction rate	r	Measure for speed of a chemical reaction.	mol m−3 s−1	N L−3 T−1	intensive
Speed	v	Rate of change of the position of an object.	m s−1	L T−1	scalar
Specific energy		Amount of energy present per unit mass.	J kg−1	L2 T−2	intensive
Specific heat capacity	c	Heat capacity per unit mass.	J kg−1 K−1	L2 T−2 Θ−1	intensive
Specific volume	v	The volume occupied by a unit mass of material (reciprocal of density).	m3 kg−1	L3 M−1	intensive
Spin	S	Intrinsic property of particles, roughly to be interpreted as the intrinsic angular momentum of the particle.	kg m2 s−1	M L2 T−1
Stress	σ	Amount of force exerted per surface area.	Pa	M L−1 T−2	2-tensor. (or scalar)
Surface tension	γ	Amount of work needed to change the surface of a liquid by a unit surface area.	N m−1 or J m−2	M T−2
Thermal conductivity	k	Measure for the ease with which a material conducts heat.	W m−1 K−1	M L T−3 Θ−1	intensive
Torque	τ	Product of a force and the perpendicular distance of the force from the point about which it is exerted.	N m	M L2 T−2	pseudovector
Velocity	v→	Speed of an object in a chosen direction.	m s−1	L T−1	vector
Volume	V	The three dimensional extent of an object.	m3	L3	extensive
Wavelength	λ	Distance between repeating units of a propagating wave.	m	L
Wavenumber	k	Reciprocal of the wavelength.	m−1	L−1
Weight	w	Amount of gravitation force exerted on an object.	newton (N = kg m s−2)	M L T−2
Work	W	Energy 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−2	scalar