12.1.2—The concept of angular speed

Angular speed ω is angular displacement per unit time: ω=∆θ/∆t, measured in rad s⁻¹.

For uniform rotation use a constant value; for changing rotation distinguish average from instantaneous angular speed.

A wheel turning through 12 rad in 3.0 s has average angular speed 4.0 rad s⁻¹.

Angular speed is not ordinary linear speed, and radians are treated as dimensionless in units but still encode rotation.