Velocity

Velocity of a body is the distance travelled by it per unit time in a particular direction. In other words, velocity is the speed of the body in a definite direction. Velocity = Displacement/Time

Average velocity
It is defined as the total displacement of a body divided by the total time taken to cover that displacement. i.e. Average velocity = total displacement/total time If x, and x₂ are the positions of an object at times t, and t₂, then the average velocity from t, to t₂ is given by Average velocity = X2 - X1/T2 - T1 = Δx / Δt Where X is 'Displacement' and T is 'Time'.

When the velocity of a body moving in a straight line is changing continuously at a uniform rate, then the average velocity is given by the arithmetic mean of initial and final velocities for a given period of time. Average velocity = initial velocity + final velocity / 2

Uniform velocity
A body is said to have uniform velocity, if it covers equal distance in equal intervals of time in a particular direction, no matter how small these time intervals may be. An object travelling with uniform velocity is said to have uniform motion along a straight line.

Example - A car moving along a straight line with a constant speed is said to have uniform velocity.

Non-uniform Velocity
A body is said to have variable velocity if

It has non-uniform speed or


 * Its direction of motion keeps on changing or

Both its speed and direction changes with time.

An object travelling with non-uniform velocity is said to have non-uniform motion.

Ex. A) a person running on a circular track. B) a car moving on a crowded road.

Instantaneous Velocity
The velocity of an object at a particular instant or at a particular point of its path is called instantaneous velocity i.e., the instantaneous velocity of the object can be defined as the average velocity over an infinitesimally small time interval.