Angular velocity : The time rate of angular displacement of a particle performing circular motion is called the angular velocity.
1. If the particle has an angular displacement \(δ\bar{θ}\) in a short time interval δt, its angular velocity
\(\bar{\omega}\) = \(\lim\limits_{δt \to θ} \) \(\frac{δ\bar{θ}}{δt}\) = \(\frac{d\bar{θ}}{dt}\)
2. \(\bar{\omega}\) is a vector along the axis of rotation, in the direction of \(d\bar{θ}\), given by the right hand thumb rule.
Right hand thumb rule : If the fingers of the right hand are curled in the sense of revolution of the particle, then the outstretched thumb gives the direction of the angular displacement.
[Note : Angular speed, ω = | \(\bar{\omega}\) | = \(\frac{d{θ}}{dt}\) is also called angular frequency. ]
