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Physics LibreTexts

Appendix A: Units

Units Used in Physics (Fundamental units in bold)

Quantity Common Symbol Unit Unit in Terms of Base SI Units
Acceleration $$\vec{a}$$ m/s2 m/s2
Amount of substance n mole mol
Angle $$\theta, \phi$$ radian (rad)  
Angular acceleration $$\vec{\alpha}$$ rad/s2 s-2
Angular frequency $$\omega$$ rad/s s-1
Angular momentum $$\vec{L}$$ kg • m/s2 kg • m/s2
Angular velocity $$\vec{\omega}$$ rad/s s-1
Area A m2 m2
Atomic number Z    
Capacitance C farad (F) A2 • s4/kg • m2
Charge q, Q, e coulomb (C) A • s
Charge density:      
Line $$\lambda$$ C/m A• s/m
Surface $$\sigma$$ C/m2 A• s/m2
Volume $$\rho$$ C/m3 A• s/m3
Conductivity $$\sigma$$ $$\frac{1}{\Omega \cdotp m}$$ A2 • s3/kg • m3
Current I ampere A
Current density $$\vec{J}$$ A/m2 A/m2
Density $$\rho$$ kg/m3 kg/m3
Dielectric constant $$\kappa$$    
Electric dipole moment $$\vec{p}$$ C• m A• s • m
Electric field $$\vec{E}$$ N/C kg • m/A • s3
Electric flux $$\Phi$$ N • m2/C kg • m3/A • s3
Electromotive force $$\varepsilon$$ volt (V) kg • m2/A • s3
Energy E, U, K joule (J) kg • m2/s2
Entropy S J/K kg • m2/s2 • K
Force $$\vec{F}$$ newton (N) kg • m/s2
Frequency f hertz (Hz) s-1
Heat Q joule (J) kg • m2/s2
Inductance L henry (H) kg • m2/A2 • s2
Length: \(\ell\), L meter m
Displacement $$\Delta x, \Delta \vec{r}$$    
Distance d, h    
Position x, y, z, \(\vec{r}\)    
Magnetic dipole moment $$\vec{\mu}$$ N • J/T A • m2
Magnetic field $$\vec{B}$$ tesla (T) = Wb/m2 kg/A • s2
Magnetic flux $$\Phi_{m}$$ weber (Wb) kg • m2/A • s2
Mass m, M kilogram kg
Molar specific heat C J/mol • K kg • m2/s• mol • K
Moment of inertia I kg • m2 kg • m2
Momentum $$\vec{p}$$ kg • m/s kg • m/s
Period T s s
Permeability of free space $$\mu_{0}$$ N/A2 = H/m kg • m/A2 • s2
Permittivity of free space $$\varepsilon_{0}$$ C2/N • m= F/m A2 • s4/kg • m3
Potential V volt (V) = J/C kg • m2/A2 • s3
Power P watt (W) = J/s kg • m2/s3
Pressure p pascal (Pa) = N/m2 kg/m • s3
Resistance R ohm (\(\Omega\)) = V/A kg • m2/A2 • s3
Specific heat c J/kg • K m2/s• K
Speed v m/s m/s
Temperature T kelvin K
Time t second s
Torque $$\vec{\tau}$$ N • m kg • m2/s2
Velocity $$\vec{v}$$ m/s m/s
Volume V m3 m3
Wavelength $$\lambda$$ m m
Work W joule (J) = N • m kg • m2/s2

Contributors

  • Samuel J. Ling (Truman State University), Jeff Sanny (Loyola Marymount University), and Bill Moebs with many contributing authors. This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).