Units
The answers you enter as the solutions to your WebWork problem sets must conform to the following conventions, in order to be interpreted and graded correctly.
Contents
Problems requiring a numerical answer
Most answers consist of a numerical value followed by an abbreviation for the appropriate units of the physical quantity.
If no MathQuill pallet is present a space must separate the numerical value from the units, as in for example 1.234 m
.
If a MathQuill pallet is being used then a double quote (which invokes text or tT mode) must separate the value from the units: for example 9.18 "m/s^2
Numerical values
The numerical value may be written as a floating point decimal, for example 0.00314159
, or in scientific notation as either 3.14159E3
(as in FORTRAN) or 3.14159*10^3
(with *
signifying multiplication, and ^
signifying exponentiation; note in using the FORTRANlike notation, you must use capital "E" and not small "e"). In place of a specific number for the numerical part of an answer, you may also use algebraic expressions. For example, (6+4)/2
is the same as writing 5
. To see the syntax required for such expressions, as well as to see which special functions and numerical constants are recognized, see the section on Available_Functions. Note that trigonometric functions assume the argument is expressed in radians and not degrees.
Units
The units may be any compound expression of the form:[unit]_{1}^n_{1}*[unit]_{2}^n_{2}*...*[unit]_{3}^n_{3}/ [unit]_{4}^n_{4}*[unit]_{5}^n_{5}*...*[unit]_{6}^n_{6}
where [unit]_{i}
is any of the unit abbreviations listed below, and the n_{i}
are positive or negative integers. The string of units before the /
denote the numerator of the compound expression, while those following the /
denote the denominator of the compound expression. There may be only one /
in a given compound unit expression and no spaces are allowed within the units expression.
The abbreviations for units that are recognized by WebWork are:
abbrev.  unit name  dimension  equivalence in fundamental units 
FUNDAMENTAL MKS UNITS  
kg

kilograms  mass  
m

meters  length  
s

seconds  time  
OTHER BASIC UNITS  
deg

degree  angle  1 deg = pi/180 rad

rad

radian  angle  1 rad = 180/pi deg

ms

millisecond  time  1 ms = 0.001 s

min

minute  time  1 min = 60 s

hr

hour  time  1 hr = 60 min = 3600 s

day

day  time  1 day = 24 hr = 8.64E4 s

yr

year  time  1 yr = 365.25 day = 3.15576E7 s

km

kilometer  length  1 km = 1000 m

cm

centimeter  length  1 cm = 0.01 m

mm

millimeter  length  1 mm = 0.001 m

micron

micrometer  length  1 micron = 10^6 m

um

micrometer  length  1 um = 10^6 m

nm

nanometer  length  1 nm = 10^9 m

A

Angstrom  length  1 A = 10^10 m

in

inch  length  1 in = 0.0254 m

ft

feet  length  1 ft = 12 in = 0.3048 m

mi

mile  length  1 mi = 5280 ft = 1609.344 m

lightyear

light year  length  1 lightyear = 9.46E15 m

L

liter  volume  1 L = 10^3 m^3

ml

milliliter  volume  1 ml = 10^3 L = cm^3

cc

cubic centimeter  volume  1 cc = 10^3 L = cm^3

knots

nautical miles per hour  velocity  1 knots = (1852/3600) m/s

g

gram  mass  1 g = 10^3 kg

slug

slug  mass  1 slug = 14.6 kg

Hz

Hertz  frequency  1 Hz = 1 s^1

kHz

kiloHertz  frequency  1 kHz = 1000 Hz = 10^3 s^1

MHz

megaHertz  frequency  1 MHz = 10^6 Hz = 10^6 s^1

rev

revolutions  period  1 rev = 2pi rad

cycles

cycles  period  1 cycles = 1 rev = 2pi rad

degK

degrees Kelvin  temperature 

degC

degrees Centigrade  temperature 

degF

degrees Fahrenheit  temperature 

COMPOUND UNITS  
N

Newton  force  1 N = 1 kg*m/s^2

microN

microNewton  force  1 microN = 10^6 N = 10^6 kg*m/s^2

uN

microNewton  force  1 uN = 10^6 N = 10^6 kg*m/s^2

J

Joule  energy  1 J = 1 N*m = 1 kg*m^2/s^2

kJ

kiloJoule  energy  1 kJ = 1000 J = 10^3 kg*m^2/s^2

lbf

footpound  energy  1 lbf = 1.355 N*m = 1.355 kg*m^2/s^2

W

Watt  power  1 W = 1 J/s = 1 kg*m^2/s^3

kW

kiloWatt  power  1 kW = 1000 W = 10^3 kg*m^2/s^3

dyne

dyne  force  1 dyne = 10^5 N = 10^5 kg*m/s^2

erg

erg  energy  1 erg= 10^7 J = 10^7 kg*m^2/s^2

lb

pound  force  1 lb = 4.45 N = 4.45 kg*m/s^2

ton

ton  force  1 ton = 2000 lb = 8900 kg*m/s^2

Pa

Pascal  pressure  1 Pa = 1 N/m^2 = 1 kg/m*s^2

kPa

kiloPascal  pressure  1 kPa = 1000 Pa = 10^3 kg/m*s^2

atm

atmosphere  pressure  1 atm = 14.7 lb/in^2 = 1.01E5 Pa = 1.01E5 kg/m*s^2

cal

calorie  energy  1 cal = 4.19 J = 4.19 kg*m^2/s^2

kcal

kilocalorie  energy  1 kcal = 1000 cal = 4190 kg*m/s^2

eV

electron volt  energy  1 eV = 1.60E19 J = 1.60E9 kg*m^2/s^2

kWh

kiloWatt hour  energy  1 kWh = 3.6E6 J = 3.6E6 kg*m^2/s^2

Units Available in WeBWorK
Some WeBWorK problems ask for answers with units. Below is a list of basic units and how they need to be abbreviated in WeBWorK answers. In some problems, you may need to combine units (e.g, velocity might be in ft/s
for feet per second).
Units need to come at the end of the answer blank . If MathQuill (the vertical math pallet on the side of the page) is being used then the unit should be preceded by a double quote  e.g. 9.81 "m/s^2 which invokes text mode (tT) for the units. This prevents MathQuill from rewriting the units in two dimensional typeset form. Before MathQuill was in use the units had to be preceded by a space (in most cases).
Unit  Abbreviation 

Time  
Seconds  s 
Minutes  min 
Hours  hr 
Days  day 
Years  yr 
Milliseconds  ms 
Distance  
Feet  ft 
Inches  in 
Miles  mi 
Meters  m 
Centimeters  cm 
Millimeters  mm 
Kilometers  km 
Angstroms  A 
Light years  lightyear 
Mass  
Grams  g 
Kilograms  kg 
Slugs  slug 
Volume  
Liters  L 
Cubic Centimeters  cc 
Milliliters  ml 
Force  
Newtons  N 
Dynes  dyne 
Pounds  lb 
Tons  ton 
Work/Energy  
Joules  J 
kilo Joule  kJ 
ergs  erg 
foot pounds  lbf 
calories  cal 
kilo calories  kcal 
electron volts  eV 
kilo Watt hours  kWh 
Electric  
Charge Coulombs  C 
Voltage Volts  V 
milivolts  mV 
kilovolts  kV 
megavolts  MV 
Capacitance Farad  F 
milifarad  mF 
microfarad  uF 
Resistance ohms  ohm 
kiloohm  kohm 
Misc  
Amperes  amp 
Moles  mol 
Degrees Centrigrade  degC 
Degrees Fahrenheit  degF 
Degrees Kelvin  degK 
Angle degrees  deg 
Angle radians  rad 