Some combinations of SI units are given special names. 2 as the energy unit. The SI convention is that if there is no number in front of the unit, then the unit is written as a full word. Panel 7 Now test yourself on the SI special names. Do Quiz 3 .
Some quantities have no dimensions.
For example, the sine of an angle is defined as the ratio of the lengths of two particular sides of a triangle. That's the reason for cycles being written in parentheses above. Now try Quiz 4 . Try NOT to look at the table while you do it. We've now done all the basics so let's get into some fine points.