§§ Velocity: The rate of displacement (or) displacement per unit time is called velocity.
\(\therefore\)Velocity \(
\left( {\mathop v\limits^ \to } \right)\, = \,\frac{{Displacement}}
{{time}} = \frac{{\overrightarrow S }}
{t}
\)
* velocity is a vector quantity.
units: CGS Unit : cm/s, SI unit: m/s,
Note:* The velocity of a body can be zero, negative or positive.
* The numerical value of velocity of a body can be equal to speed only if the body is moving along a straight line in the same direction.
* The velocity of a body can never be greater than the speed of that body.
§§ Uniform velocity: If a body travels equal displacements in equal intervals of time then the body is said to be travelling with uniform velocity.
§§ Non - uniform (or) variable velocity: If a body covers cover unequal displacements in equal intervals of time then it is said to be travelling with variable velocity.
AVERAGE VELOCITY:
For a particle in motion (uniform or non- uniform), the ratio of total displacement to the total time interval is called Average velocity.
\(
\text{Average velocity } = \frac{{\text{Total displacement}}}
{{\text{Total time}}}
\)
Suppose a particle displaces from P1 to P2 , in a time interval \(\Delta t\). If x1 is initial position and x2 is final position then
Average velocity = (v)\(
= \frac{{x_2 - x_1 }}
{{\Delta t}}
\) .