Editing Angular displacement (section)

== Example ==
In the example illustrated to the right (or above in some mobile versions), a particle or body P is at a fixed distance ''r'' from the origin, ''O'', rotating counterclockwise. It becomes important to then represent the position of particle P in terms of its polar coordinates (''r'', ''θ'').  In this particular example, the value of ''θ'' is changing, while the value of the radius remains the same.  (In rectangular coordinates (''x'', ''y'') both ''x'' and ''y'' vary with time.) As the particle moves along the circle, it travels an [[Arc (geometry)|arc length]] ''s'', which becomes related to the angular position through the relationship:
:<math>s = r\theta .</math>