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.
A space *must* separate the numerical value from the
units, as in for example `1.234 m` .
### 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 Accepted math 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` |
`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` |
## Multiple choice problems
Some problems require you to enter all of several possible choices that are
correct, for example `ACEG` . In this case, enter the letters
corresponding to the choices in one string *without* any spaces
separating the letters. ## Problems requiring a symbolic functional expression for the answer
Follow the conventions explained in the WebWork
section on Accepted math functions.
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