Action has the dimension length squared mass per time. The SI composite unit of action is the kilogram meter squared per second.

Maple knows the units of action listed in the following table.

An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI- indicate that the unit takes only positive and negative SI prefixes, respectively.  Refer to a unit in the Units package by indexing the name or symbol with the context, for example, planck[standard]; by using an abbreviation, for example, h_bar; or, if the context is indicated as the default, by using only the unit name or symbol, for example, planck.

The units of action are defined as follows.

A standard planck is defined as a joule second.

An atomic planck is defined as $\frac{h}{2\mathrm{\pi }}$ standard planck where h is the Planck constant.

$\mathrm{convert}\left('\mathrm{planck}'\,'\mathrm{dimensions}'\,'\mathrm{base}'=\mathrm{true}\right)$

$\frac{{\mathrm{length}}^2\mathrm{mass}}{\mathrm{time}}$

$\mathrm{convert}\left(1\,'\mathrm{units}'\,\frac{{'m'}^2'g'}{'s'}\,'\mathrm{planck}'\right)$

$\frac{1}{1000}$

$\mathrm{convert}\left(1\,'\mathrm{units}'\,\frac{{'m'}^2'g'}{'s'}\,'\mathrm{planck}\left[\mathrm{Atomic}\right]'\right)$

$9.482521724\times {10}^{30}$