# Physics Quantities and Units

SI Units

Developer's notes

• Radians have no units. A radian is a ratio of two lengths. So how should radians be displayed here?

SI Base Units

Quantity / Symbol / In other Symbols / Unit Name / SI
Unit / In other SI Units / In SI
Base Units
mass / m / - / kilogram / kg / - / kg
length, distance / l, d / - / meter / m / - / m
time / t / - / second / s / - / s
electric current / I / - / ampere / A / - / A
thermodynamic temperature / T / - / kelvin / K / - / K
amount of substance / n / - / mole / mol / - / mol
luminous intensity / I / - / candela / cd / - / cd
SI Supplementary Units
Quantity / Symbol / In other Symbols / Unit Name / SI
Unit / In other SI Units / In SI
Base Units
plane angle / - / radian / rad / - / -
SI Derived Units
Quantity / Symbol / In other Symbols / Unit Name / SI
Unit / In other SI Units / In SI
Base Units
area / A / - / square meter / - / - / m2
volume / V / - / cubic meter / - / - / m3
speed / s / d/t / meters per second / - / - / m/s
velocity / v / d/t / meters per second / - / - / m/s
acceleration / a / ∆v/t / meters per second squared / - / - / m/s2
force / F / ma / newton / N / - / kgm/s2
momentum / P / mv / momentum / - / - / kgm/s
rotational speed / radians per second / - / - / rad/s
rotational velocity /  / radians per second / - / - / rad/s
rotational inertia / I / ∑mr2 / ? / - / - / kgm2
angular acceleration /  / /t / radians per second squared / - / - / rad/s2
torque /  / I
(Fd?) / newton-meter / Nm / - / kgm2/s2
angular momentum / I
(mvr) / ? / - / - / kgm2rad/s
work
energy
potential energy
kinetic energy
quantity of heat / W
E
PE
KE
Q / Fd
Fd
(mv2)/2 / joule / J / Nm / kgm2/s2
power / P / W/t / watt / W / J/s / kgm2/s3
mass density /  / m/V / kilograms per cubic meter / - / - / kg/m3
pressure / p / F/A / pascal / Pa / N/m2 / kg/ms2
electric charge / q / - / coulomb / C / - / As
electric field / E / F/q
electric potential / V / IR
E/q / volt / V / A
electric resistance / R / V/I / ohm /  / V/A
electric power / P / IV / watt / W / AV
capacitance / C / - / farad / F / As/V
frequency / f / 1/t / hertz / Hz / - / s-1
magnetic field / B / F/p / Tesla / T

Physics symbols

• Base units are not italicized. kg (kilograms), m (meters), s (seconds)
• Quantities are italicized. m (mass),
• ? Vectors are boldface. F (force)
• SI derived units

Item / symbol / symbol description / type
meter / m / m / base unit
kilogram / kg / kg / base unit
second / s / s / base unit
ampere / A / uppercase a / base unit
temperature / K / base unit
mole / mol / base unit
candela / cd / base unit
velocity / v / italic v / quantity
mass / m / italic m / quantity
distance / d / italic v / quantity
tangential speed / v / quantity
rotational speed /  / lowercase Greek omega / quantity
radius / r / italic / quantity
revolution / rev
force / N / uppercase n / SI derived unit
joule / J / J / SI derived unit
watt / W / SI derived unit
pascal / Pa / SI derived unit
hertz / Hz / SI derived unit
coulomb / C / SI derived unit
volt / V / SI derived unit
ohm /  / uppercase Greek omega / SI derived unit
Farad / F / SI derived unit
tesla / T / SI derived unit
weber / Wb / SI derived unit
henry / H / SI derived unit
gravitational constant / G / constant
speed of light / c / constant
Avogadro's number / NA / constant
Gas constant / R / constant
Boltzmann's constant / k / constant
charge on electron / e / constant
Stefan-Boltzmann constant /  / lower case greek s / constant

Physical Constants

Quantity / Symbol / Number / SI Units / In SI
Base Units
gravity on Earth / g / 9.8 / m/s2 / m/s2
gravitational constant / G
average radius of Earth orbit / -

Extra. physics qty 03dk.doc11/31/19