Some general instructions for using CAPA:

With your internet browser (probably Netscape or Internet Explorer) go to the CAPA home page at http://capa.colorado.edu/CAPA/class.html
or click on the link to the CAPA home page in your course Web page.

Select your course (phys2020) from the menu.

Sign in with your student ID (9 digits, no spaces or dashes) and your CAPA ID (on your CAPA assignment).

To input your homework, select "Try current set".

Write your answers in the answer boxes, and press the "Submit all answers" button.

Important ! AVOID using the refresh/reload button of your Web browser (in the upper left corner)! Every time you hit reload/refresh, you use up one of your CAPA tries!

To enter answers with scientific notation, use the format

3.2E-8 (=3.2 x 10^-8 =3.2*10^-8)

5.5E+11 or 5.5E11 (=5.5x10¹¹) (=5.5*10^11).

Note: Please use no spaces either before or after the "E", for scientific notation (i.e. NOT 3.2 E -8).

CAPA usually wants 3 or more sig.figs. Don't enter an answer like "0.4". Enter it as "0.400" or "4.00E-2". CAPA thinks "200" has only 1 sig.fig. because it doesn't know whether you are rounding 199.99 to 200 or 245 to 200 . To make CAPA understand, write it as 200.0 or 200. (notice the extra decimal point) or 2.00E2.

Enter numerical answers without commas. (Example: 342000 J but NOT 342,000 J)

If CAPA thinks the units or the sig.figs. are wrong, it won't even look at your numerical answer. Do not interpret an "incorrect units" warning or an "adjust sig.figs." warning as an indication that the numerical answer is correct.

Many answers require units. Use the standard SI abbreviations for units (N for newtons, kg for kilograms). Leave a space between the number and the units.

Use * for multiply, / for divide, ^ = shift-6 for superscript, _ = shift-minus for subscript. Use these special symbols only when constructing units.

Examples: If answer is acceleration a = 4.53 m/s² , enter 4.53 m/s^2. The units of momentum are kg*m/s.

Always enter numerical answers as pure numbers, not expressions. For example, if the answer is 1/3, you must enter 0.333 or 0.3333, etc (NOT 1/3) If CAPA sees any punctuation marks, * =asterisk, /=slash, ^=caret, _=underscore ,=comma, it will interpret these as an attempt to create a unit and will give the "incorrect units" warning.

On some problems hints are given after incorrect attempts. The hint will always be given after an incorrect answer. So if the hint say "Units are rad/s", understand that it will always say this even if your units are correct. CAPA's hints are not "intelligent", I write them a week ahead of time, and it's the same hint for everyone who gets the problem wrong, so it may or may not have any relevance to you.

Here are a few more "frequently asked questions" about CAPA.