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Velocity Definition

The term speed and Velocity gives a sense of understanding of an object and how rapid or slow it is moving. We encounter a situation where we must judge which object is moving rapidly or slowly. It becomes easy to say when the object is heading in the same direction. However, the case of judging becomes tough when the direction of motion is in the opposite direction. To overcome this situation, the idea of Velocity helps a lot.

Velocity Definition


Velocity is the rate of change of the object's position concerning a frame of reference and time. The definition might seem complex, but Velocity is understood as speeding in a specific direction for a common purpose. The Velocity has been categorized as the vector quantity. Those quantities with direction and magnitude (speed) are being said as Velocity. It is referred to as an accelerating body if there is variation in the Velocity or the direction.

The Velocity has SI unit = meter per second

Initial and Final Velocity

The initial Velocity shows that when a body travels when gravity exerts a force on the body. The final Velocity determines the direction and speed of the traveling object when it achieves maximum Acceleration.

Methods to Determine the Final Velocity

Determination of final Velocity is easy and needs a basic concept with little concept of physics.

  • Find out the body's actual Velocity and divide by the time. It is time the object moves a given distance to the total distance. The equation will turn out to be V = d/t. The V denotes Velocity, t denotes time, and d denotes the distance.
  • Find out the body's Acceleration.
    1. Divide the body's mass by force and multiply the result by time. It is the time taken by the body to accelerate. For example, the if the body mass is 20 kg and has a force of 10 N exerted on it, then the resulting Acceleration comes out to be 2 m/s.

Add the quantity that resulted from steps 1 and Step 2 to determine the final Velocity. Let's say the initial Velocity was 4 m/s, your body acceleration was 3 m/s, your object acceleration was 4 m/s, and the final Velocity was 7 m/s.

Constant Velocity

It is the simplest form of motion. We observe constant motion when a body slides on a horizontal and low-friction surface.

Velocity Definition

The above graph represents displacement versus time, and an object travels uniformly. The straight line which has emerged can be expressed algebraically:

x= x0 + vt

In the equation,

X not = displacement at a time t

T = time t

V = Constant Velocity of the object

Velocity Definition

Unit of the Velocity

m/s = SI unit of the Velocity

Dimension = L/T

Relation between Speed and Velocity

Velocity Definition

Speed and Velocity are not similar, and they are confusing to the students. Differences exist between the speed and the Velocity. Speeds only indicate how the object/ body is moving, but the Velocity, along with speed, also indicates the direction of the body traveling. Speed is termed as the function of the distance covered/travelled, and Velocity is termed as the function of displacement.

  • Instantaneous Velocity: It is the object's Velocity at a given time.
  • Average Velocity: It is the total displacement divided by the total time, and it is represented as Velocity Definition ?x denotes the total displacement of the object and ?tdenotes the time.
  • Average Velocity: It is always equal to or less than the average speed. The reason is that displacement cannot be greater than the distance covered, but the distance covered can be greater than the displacement.

Examples of Velocity

Question: Ritik goes to the office in the government's car every evening. His office is 8 km from his residence, and he takes 15 mins to travel, but when he sees the speedometer of the car. It shows ununiform reading always. So how will he know the actual Velocity?

Answer: The average Velocity of the Ritik vehicle can be determined by:

For the understanding, let us assume that the car is travelling in a straight path and will change the time units to hours.

15 mins = 0.25 hrs

We know the formula for the determination of average Velocity

Velocity Definition

= 8 kilo meter/ 0.25 hrs

= 32 kilometers/hr

We can observe that the car may change its speed; it travels an equal amount of distance in the same amount of time, but the average Velocity will remain constant.

Dissimilarities Between Speed and Velocity


  • It is a quantitative value and shows how an object moves rapidly.
  • It comes under the scalar quantity
  • It is the rate of change in length/distance
  • The speed of the object cannot be a negative value
  • It indicates the body's rapidity and is considered a prime indicator.
  • It has been defined as the path covered by the body in the unit of time.


  • Velocity indicates the direction of movement of the body.
  • It is under the category of a vector quantity
  • Rate of change of displacement
  • It is very much possible the Velocity of the object can become zero.
  • Velocity indicates position and rapidity, which is a prime indicator.
  • It can be defined as the displacement of the body with unit time.

Relation Between the Velocity and the Acceleration

Basis Acceleration Velocity
Definition The change in Velocity (Final Velocity - Initial Velocity) with respect to time is referred to as Acceleration. Velocity is the given speed of the object and indicates the position of the object.
Calculation Velocity Displacement
Nature of the Quantities Vector Vector
Formula Change in Velocity/ Time dv/ dt Displacement/ Time
Units Meter/ second2 Meter/ second

Frequently Asked Questions

Question: Can we add the vectors algebraically?

Answer: Addition of the vector is impossible because they have the directions along with the magnitude. The sum cannot be performed on the directions algebraically.

Question: Define the instantaneous speed.

Answer: The speed of the object at a particular moment is called Instantaneous speed.

Question: Determine the Acceleration and Velocity of the round object when it is thrown in the air.

Answer: The Acceleration and Velocity of the object will increase if it is thrown in the air.

Numerical Questions

Question: A bullock cart has covered a 100 m path in 10 seconds. Determine the Velocity of the object.

Answer: We know that

Distance covered: 100 meters

Time: 10 seconds

Velocity = Displacement/ time

= 100/ 10

= 10 m/s

The Velocity of the bullock cart is ten m/s.

Question: A horse is moving towards the north at the Velocity of 5m/s, and it has taken 200 seconds to reach its destination. Determine the path covered by the horse.

Answer: We have been asked to find displacement.

The quantities given to us are

The Velocity of the horse = 5m/s

Time is taken by the horse = 200 m/s

We know the formula of the Velocity,

Velocity = Displacement/ Time

Velocity x time = Displacement

5 x 200 = 1000 m.

The distance covered by the horse is 1000 meters.

Question: Ram goes to school with a velocity of 4 m/s, and the distance between the school and his home is 400m. Determine how much Ram will take to reach the school.

Answer: The given quantities are:

Velocity of the Ram = 4 m/s

Displacement = 400m

We know the formula

Velocity = Displacement / Time

Time = Displacement/ Velocity

Time = 400 / 4

Time = 100 sec.

The time taken by the Ram is 100 seconds.

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