1: \label{Physical_Units}
2: \section*{Physical Units Accepted by LON-CAPA}
3: The following subsections show the physical units that LON-CAPA accepts.
4: The symbols must be used when entering the units, for example {}``35 kg''.
5:
6: Note that compound units are formed by using *, / and ^. For example, an acceleration might
7: be in terms of ``m/s^2'' or meters per second squared. This could also be expressed as``m/s/s''.
8: Units of Newton-meters (for torque) would be entered as ``N*m''. Parentheses may be used to guarantee
9: the correct sense of the unit. Kilometers per Ampere-hour could be written as ``km/(A*hr)'' or
10: ``km/A/hr'' but not ``km/A*hr''. The last option would be interpreted as kilometer times hours per Ampere.
11:
12: LON-CAPA will automatically perform some conversions between units of the same dimension
13: when units are provided for a problem.
14: You can provide an answer of ``1.45 km'' for a distance.
15: If the computer expects the answer in cm, it will convert your answer before comparing
16: against the numerical solution.
17:
18: Please note that if your units are inappropriate, the computer has no way of checking
19: the appropriateness of your answer. If units are required, only once appropriate
20: units are provided will the system check your numerical answer.
21:
22: \subsection*{Base Units}
23: \begin{verbatim}
24: # name symbol comment
25:
26: meter m # length
27: kilogram kg # mass
28: second s # time
29: ampere A # electric current
30: kelvin K # thermodynamic temperature
31: mole mol # amount of substance
32: candela cd # luminous intensity
33: decibel dB # log of pressure amplitude
34: \end{verbatim}
35: \subsection*{Prefixes}
36: \begin{verbatim}
37: # Prefix symbol factor
38:
39: yotta Y 10^{24}
40: zetta Z 10^{21}
41: exa E 10^{18}
42: peta P 10^{15}
43: tera T 10^{12}
44: giga G 10^9
45: mega M 10^6
46: kilo k 10^3
47: hecto h 10^2
48: deca D 10^1
49:
50: deci d 10^-1
51: centi c 10^-2
52: milli m 10^-3
53: micro u 10^-6
54: nano n 10^-9
55: pico p 10^{-12}
56: femto f 10^{-15}
57: atto a 10^{-18}
58: zepto z 10^{-21}
59: yocto y 10^{-24}
60: \end{verbatim}
61: \subsection*{Derived Units}
62: \begin{verbatim}
63: # Derived Unit
64: # name symbol comment
65:
66: gram g # mass
67: minute min # time
68: hour hr # time
69: hour h # time
70: day day # time
71: day days # time
72: year yr # time
73: pound lb # mass
74: ounce oz # mass
75: inch in # length
76: foot ft # length
77: mile mi # length
78: yard yd # length
79: nautical_mile n_mi # length, nautical mile (UK)
80: rood rood # area, rood
81: acre acre # area, acre
82: hertz Hz # frequency
83: litre L # volume
84: newton N # force
85: pound_force lbf # force
86: dyne dyn # force
87: pascal Pa # pressure, stress
88: bar bar # pressure
89: mmHg mmHg # pressure, millimeter of mercury
90: torr torr # pressure
91: atm atm # standard atmosphere
92: joule J # energy, work, heat
93: electronvolt eV # energy
94: calorie cal # energy
95: Btu Btu # energy
96: watt W # power, radiant flux
97: coulomb C # electric charge
98: volt V # electric potential, electromotive force
99: ohm ohm # electric resistance, use this in /ANS
100: ohm ohms # electric resistance
101: ohm Ohm # electric resistance
102: ohm Ohms # electric resistance
103: mho mho # electric conductance
104: mho mhos # electric conductance
105: mho Mho # electric conductance
106: mho Mhos # electric conductance
107: siemens S # electric conductance
108: farad F # electric capacitance
109: tesla T # magnetic flux density
110: weber Wb # magnetic flux
111: henry H # inductance
112: radian rad # plane angle
113: degree deg # plane angle (Pi rad=180 deg)
114: steradian sr # solid angle
115: lumen lm # luminous flux
116: lux lx # illuminance
117: becquerel Bq # activity (radioactive)
118: gray Gy # absorbed dose (of radiation)
119: sievert Sv # dose equivalent (dose equivalent index)
120: astroUnit AU # mean distance earth to sun
121: celcius degC # multiplicatively OK
122: farenheight degF # multiplicatively OK
123: molarity M # chemisty
124: amu amu # atomic mass unit
125: amu u # atomic mass unit
126: \end{verbatim}
127: \subsection*{Interpretation}
128: The coded units are interpreted in the order of basic unit,
129: derived unit, then prefix. For example, ``T'' will be matched against
130: ``tesla'' instead of considered the prefix ``T''. Another example is that
131: ``min'' will match
132: ``minutes'' instead of treated as a combination of the prefix ``m'' and units.
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