Velocity

Velocity is simply defined as the displacement of the object as a function of time or we can say it is the rate at which the body travels or changes its position.

Velocity takes into account the displacement of the body, not the distance.

So Displacement is defined as the shortest distance between two points while the distance takes into account the total measurement.

For eg if we consider a circular field with a radius of 10cm and a boy covers it then if we need to find out the displacement then it will be the shortest distance Covered that is the distance travelled across yeh diameter which will be 20 cm while the distance will be the circumference of the circle. 

Velocity is the measure of displacement of the body in a given time and in a particular direction. The significance of direction while measuring the velocity is that it is a vector quantity and hence it takes into account both the magnitude as well as direction .

Difference between speed and velocity 

Speed is defined as the distance travelled by a body per unit time while velocity is the displacement of a body in a given time and direction.So we can say that these are some of the differences between speed and velocity-:

• Speed takes into account the distance travelled while velocity takes into account the displacement.
• Speed is not defined in terms of direction while velocity is always in a particular direction . For eg a car is travelling with 20m/s is the speed of the car while if one says that the car travels with a speed of 20m/s in the east direction or west direction then it is velocity if the car that is discussed.
• Speed is how fast you are travelling that is Distance covered within a particular time but velocity is the speed of the object or car in a particular direction.So we can say speed in a particular direction is velocity .So 

Speed =  Distance (m)/ Time (s)———–1

While ,

velocity = Displacement (m)/Time (s)——2

• In comparison of the two we can say that speed = Velocity if distance = displacement .
• Speed and velocity have the same SI unit but speed is a scalar while velocity is a vector.
• The magnitude part of velocity is speed in case yeh distance and displacement is same .

SI unit of velocity 

The SI unit of velocity is m/ s it is derived by substituting the SI unit of Displacement and time in the formula of Velocity that is as follows 

Velocity = Displacement ( m)/ Time( s)

V= D/T 

Where V = velocity , D= Displacement ,T = time . As the SI unit of displacement is Metre ( m) and the SI unit of time is Second (s) .

So, it comes out to be m/s.

The other units of velocity can be Kilometres per hour ( km/s) , Foot per second (Ft/s, fps ) or miles per hour ( mph, MPH ).

Types of velocity 

Velocity is basically of two types these are 

• Uniform velocity – when a body travels equal displacement in equal intervals of time in the same direction it is known as Uniform velocity.
• Non-uniform velocity- When a body travels unequal displacement in an equal interval of time it is known as Non-uniform velocity.

Some other types of velocity

• Relative velocity-There is also another type of velocity that is when the two objects are in motion and the velocity one object is found in relation to the other this is known as Relative velocity.It is used when we need to find the velocity of a moving body in relation to other moving body thus relative word is used. For example if a car is moving with a velocity of 20m/s in the east direction while the bus is moving in west direction with a speed of 25m/s then we need to find the relative velocity .
• Average Velocity – It is an average in terms of the displacement and the time . Average Velocity is the total displacement in a particular direction to the total time taken.
• Instantaneous velocity – as the word suggests it is the distance travelled by the body in a particular instant of time that is very small or we can say that it is velocity of an object at a specific point.
• Escape velocity -The minimum amount of Velocity that is required by an object to escape the gravitational force of the earth or any other planet is known as escape velocity.The value of escape velocity at Earth is 11.2km / s.

Conclusion 

Velocity is vector quantity it the measure of a sped of an object in a particular direction .By definition it is displacement of the object as a function of time or the change of position of object with time in a particular direction.The formula for calculation of velocity is V= Displacement / time and the SI  unit of velocity is m/s . Various other units like km/h or mph or fps can also be used.Based on whether the distance is covered in equal intervals of time and in the same direction the velocity can be uniform or non-uniform . Further other velocities like relative velocity and average Velocity are also used.