--- loncom/html/adm/help/tex/Physical_Units.tex 2003/01/24 22:32:08 1.1
+++ loncom/html/adm/help/tex/Physical_Units.tex 2006/09/13 22:01:11 1.4
@@ -2,6 +2,23 @@
\section*{Physical Units Accepted by LON-CAPA}
The following subsections show the physical units that LON-CAPA accepts.
The symbols must be used when entering the units, for example {}``35 kg''.
+
+Note that compound units are formed by using *, / and ^. For example, an acceleration might
+be in terms of ``m/s^2'' or meters per second squared. This could also be expressed as``m/s/s''.
+Units of Newton-meters (for torque) would be entered as ``N*m''. Parentheses may be used to guarantee
+the correct sense of the unit. Kilometers per Ampere-hour could be written as ``km/(A*hr)'' or
+``km/A/hr'' but not ``km/A*hr''. The last option would be interpreted as kilometer times hours per Ampere.
+
+LON-CAPA will automatically perform some conversions between units of the same dimension
+when units are provided for a problem.
+You can provide an answer of ``1.45 km'' for a distance.
+ If the computer expects the answer in cm, it will convert your answer before comparing
+against the numerical solution.
+
+Please note that if your units are inappropriate, the computer has no way of checking
+the appropriateness of your answer. If units are required, only once appropriate
+units are provided will the system check your numerical answer.
+
\subsection*{Base Units}
\begin{verbatim}
# name symbol comment
@@ -13,6 +30,7 @@ ampere A # electric curren
kelvin K # thermodynamic temperature
mole mol # amount of substance
candela cd # luminous intensity
+decibel dB # log of pressure amplitude
\end{verbatim}
\subsection*{Prefixes}
\begin{verbatim}
@@ -27,6 +45,7 @@ giga G 10^9
mega M 10^6
kilo k 10^3
hecto h 10^2
+deca D 10^1
deci d 10^-1
centi c 10^-2
@@ -45,9 +64,11 @@ yocto y 10^{-24}
# name symbol comment
gram g # mass
-hour hr # time
minute min # time
+hour hr # time
+hour h # time
day day # time
+day days # time
year yr # time
pound lb # mass
ounce oz # mass
@@ -79,6 +100,10 @@ ohm ohm # electric resist
ohm ohms # electric resistance
ohm Ohm # electric resistance
ohm Ohms # electric resistance
+mho mho # electric conductance
+mho mhos # electric conductance
+mho Mho # electric conductance
+mho Mhos # electric conductance
siemens S # electric conductance
farad F # electric capacitance
tesla T # magnetic flux density
@@ -93,6 +118,11 @@ becquerel Bq # activity (radio
gray Gy # absorbed dose (of radiation)
sievert Sv # dose equivalent (dose equivalent index)
astroUnit AU # mean distance earth to sun
+celcius degC # multiplicatively OK
+farenheight degF # multiplicatively OK
+molarity M # chemisty
+amu amu # atomic mass unit
+amu u # atomic mass unit
\end{verbatim}
\subsection*{Interpretation}
The coded units are interpreted in the order of basic unit,