# velocity

Velocity is a vector quantity specifying both the speed and direction of movement of an object in a given frame
of reference. The magnitude of velocity is the scalar quantity speed (*S*), related to distance (*s*) and time (*t*)
by the equation *S* = *s*/*t*; similarly velocity (**v**)
is related to distance and time by **v** = *ds*/*dt*.
Angular or rotational velocity is given by ω = *dθ/dt*.

## angular velocity

Angular velocity is the rate at which a rotating object sweeps out an angle relative to a fixed point. Angular velocity may be measured in radians, degrees, or revolutions per unit time.

The average angular velocity *ω* of an object moving from angle *θ*_{1} to *θ*_{2} in time *t,* is (*θ*_{1} - *θ*_{2})/*t*.
Instantaneous angular veolcity is the value approached by *ω* as *t* tends to zero. The direction associated with the angular velocity
of an object is perpendicular to the plane of its motion. The speed *v* of an object at a distance *r* from a fixed point is directly proportional
to the magnitude *ω* of its angular velocity: *v* = *rω*.