Physical Quantities

Physical Quantities

	Quantity	Definition	Formula	Units	Dimensions
	Length or Distance	fundamental	d	m (meter)	L (Length)
	Time	fundamental	t	s (second)	T (Time)
	Mass	fundamental	m	kg (kilogram)	M (Mass)
	Area	distance2	A = d2	m2	L2
	Volume	distance3	V = d3	m3	L3
	Density	mass / volume	d = m/V	kg/m3	M/L3
	Velocity	distance / time	v = d/t	m/s c (speed of light)	L/T
	Acceleration	velocity / time	a = v/t	m/s2	L/T2
	Momentum	mass × velocity	p = m·v	kg·m/s	ML/T
	Force   Weight	mass × acceleration mass × acceleration of gravity	F = m·a W = m·g	N (newton) = kg·m/s2	ML/T2
	Pressure or Stress	force / area	p = F/A	Pa (pascal) = N/m2 = kg/(m·s2)	M/LT2
	Energy or Work   Kinetic Energy   Potential Energy	force × distance mass × velocity2 / 2 mass × acceleration of gravity × height	E = F·d KE = m·v2/2 PE = m·g·h	J (joule) = N·m = kg·m2/s2	ML2/T2
	Power	energy / time	P = E/t	W (watt) = J/s = kg·m2/s3	ML2/T3
	Impulse	force × time	I = F·t	N·s = kg·m/s	ML/T
	Action	energy × time momentum × distance	S = E·t S = p·d	J·s = kg·m2/s h (quantum of action)	ML2/T
	Angle	fundamental	θ	° (degree), rad (radian), rev 360° = 2π rad = 1 rev	dimensionless
	Cycles	fundamental	n	cyc (cycles)	dimensionless
	Frequency	cycles / time	f = n/t	Hz (hertz) = cyc/s = 1/s	1/T
	Angular Velocity	angle / time	ω = θ/t	rad/s = 1/s	1/T
	Angular Acceleration	angular velocity / time	α = ω/t	rad/s2 = 1/s2	1/T2
	Moment of Inertia	mass × radius2	I = m·r2	kg·m2	ML2
	Angular Momentum	radius × momentum moment of inertia × angular velocity	L = r·p L = I·ω	J·s = kg·m2/s ћ (quantum of angular momentum)	ML2/T
	Torque or Moment	radius × force moment of inertia × angular acceleration	τ = r·F τ = I·α	N·m = kg·m2/s2	ML2/T2
	Temperature	fundamental	T	°C (celsius), K (kelvin)	K (Temp.)
	Heat	heat energy	Q	J (joule) = kg·m2/s2	ML2/T2
	Entropy	heat / temperature	S = Q/T	J/K	ML2/T2K
	Electric Charge +/-	fundamental	q	C (coulomb) e (elementary charge)	Q (Charge)
	Current	charge / time	i = q/t	A (amp) = C/s	Q/T
	Voltage or Potential	energy / charge	V = E/q	V (volt) = J/C	ML2/QT2
	Resistance	voltage / current	R = V/i	Ω (ohm) = V/A	ML2/Q2T
	Capacitance	charge / voltage	C = q/V	F (farad) = C/V	Q2T2/ML2
	Inductance	voltage / (current / time)	L = V/(i/t)	H (henry) = V·s/A	ML2/Q2
	Electric Field	voltage / distance force / charge	E = V/d E = F/q	V/m = N/C	ML/QT2
	Electric Flux	electric field × area	ΦE = E·A	V·m = N·m2/C	ML3/QT2
	Magnetic Field	force / (charge × velocity)	B = F/(q·v)	T (tesla) = Wb/m2 = N·s/(C·m)	M/QT
	Magnetic Flux	magnetic field × area	ΦM = B·A	Wb (weber) = V·s = J·s/C	ML2/QT

Note: Other conventions define different quantities to be fundamental.

Mass, energy, momentum, angular momentum, and charge are conserved, which means the total amount does not change in an isolated system.