It may be defined as the rate of change of angular displacement with the respect to time. It is usually expressed by the Greek letter ω (omega). Mathematically, angular velocity,
ω = dθ /dt
Since it has magnitude and direction, therefore, it is a vector quantity. It may be represented by a vector.
Note: If the direction of the angular displacement is constant, then the rate of change of magnitude of the angular displacement with respect to time is termed angular speed.
It may be defined as the rate of change of angular velocity with respect to time. It is usually expressed by the Greek letter α (alpha). Mathematically, angular acceleration,
α = dω /dt =(d/dt)x(dθ/dt)=d2θ/dt2
It is also a vector quantity, but its direction may not be sure as that of angular displacement and angular velocity.