If the body of rotates about the rotation axis as in, changing the angular position of the reference line from 81 to 82; the body undergoes an angular displacement.
If a body is in transnational motion along an x axis. its displacements either positive or negative, depending on whether the body is moving in the positive or negative direction of the axis. Similarly, the angular displacement of a rotating body is either positive or negative, according to the following rule.
angular displacement in the counterclockwise direction is positive, and one in the clockwise direction is negative.
The phrase clocks are negative can help you remember this rule.