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.

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 3.14159E-3 (as in FORTRAN) or 3.14159*10^-3 (with * signifying multiplication, and ^ signifying exponentiation; note in using the FORTRAN-like 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^n1*[unit]2^n2*...*[unit]3^n3/ [unit]4^n4*[unit]5^n5*...*[unit]6^n6

where [unit]i is any of the unit abbreviations listed below, and the ni 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
light-year	light year	length	1 light-year = 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	kilo-Hertz	frequency	1 kHz = 1000 Hz = 10^3 s^-1
MHz	mega-Hertz	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	micro-Newton	force	1 microN = 10^-6 N = 10^-6 kg*m/s^2
uN	micro-Newton	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	kilo-Joule	energy	1 kJ = 1000 J = 10^3 kg*m^2/s^2
lbf	foot-pound	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	kilo-Watt	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	kilo-Pascal	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 = 1.60E-19 J = 1.60E-9 kg*m^2/s^2
kWh	kilo-Watt 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	light-year
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
kilo-ohm	kohm
Misc
Amperes	amp
Moles	mol
Degrees Centrigrade	degC
Degrees Fahrenheit	degF
Degrees Kelvin	degK
Angle degrees	deg
Angle radians	rad