Average Velocity

Edited By Vishal kumar | Updated on Sep 24, 2024 10:37 AM IST

Average Velocity: Introduction

Physics uses the fundamental quantities of speed and velocity to describe the motion of objects in terms of distance, time, and direction. The most interesting concepts in physics are speed and velocity. Both are unique in their own way. Speed and velocity are the terms with two distinct meanings.
The average speed of an object is computed by dividing the distance travelled by the time it takes, which is a pretty simple mathematical formula. Velocity, on the other hand, is more difficult to calculate mathematically and can be done in a variety of methods based on the information available about the object's motion. Average velocity is computed by dividing the change in position (r) by the change in time (t) in its simplest form.

JEE Main 2025: Physics Formula | Study Materials | High Scoring Topics | Preparation Guide

JEE Main 2025: Syllabus | Sample Papers | Mock Tests | PYQs | Study Plan 100 Days

NEET 2025: Syllabus | High Scoring Topics | PYQs

This Story also Contains

Average Velocity: Introduction
Speed Definition
Velocity Definition
Average Velocity
Difference Between Speed and Velocity

Average Velocity - Definition, Formula, Difference, FAQs

Also read -

Speed Definition

Speed:- Speed is a scalar quantity, thus it does not have a direction. It implies how quickly the body is moving. If the particle's speed is high, the particle is travelling quickly, and if it is low, the particle is moving slowly.

Velocity Definition

Velocity:- Velocity is a vector quantity, which means that it has both a magnitude and a direction. It indicates how quickly the body is moving or changing its position. The velocity vector's direction is simple to determine. It moves in the same direction as the moving object. Even if the item is slowing down and the magnitude of velocity is decreasing, the object's direction will remain the same.

Being a coherent derived unit whose quantity is measured in metres per second (m/s) in the SI (metric system). "10 m/s towards west" is a vector, but "10 m/s " is a scalar. The item has a changing velocity and is said to be undergoing acceleration if there is a change in speed, direction, or both.

Related Topics Link,

JEE Main Highest Scoring Chapters & Topics

Just Study 40% Syllabus and Score upto 100%

Download E-book

Average Speed

The distance traversed by a body in a given time interval divided by time is the average speed of that body in that time interval. So, if a particle travels a given distance s in time t1 to t2, the body's average speed is:

body's average speed

In general, the formula for calculating average speed is as follows:

formula for calculating average speed

The displacement of a body in a specific time interval divided by time gives the average velocity of the body in that time interval. So, if a particle moves AB in time t1 to t2, its average velocity is:

Also read :

In general, the formula for calculating average velocity is as follows:

formula for calculating average velocity

It's important to note that average speed and average velocity without direction is not the same thing. Changes in direction over time have a greater impact on speed and velocity, as we observed with displacement and distance in the previous section.

Average Speed and Average Velocity Similarities

Both are the average of a length divided by the amount of time spent. Both average speed and average velocity have the same SI unit as other standard units of measurement. The average speed and average velocity are calculated using the same formula.

v = D/t, s = d/t, with the exception that in the first case, the direction must be given.

Also check-

Difference Between Speed and Velocity

Speed	Velocity
Speed is the rate at which the body moves a given distance.	The velocity at which an object changes position in a given direction is known as velocity.
Scalar quantity	Vector quantity
It cannot be negative	It can be zero, negative, or positive.
Even if the object changes direction, the average speed will continue to count.	Because the object's velocity changes as the direction changes, it must only move in one direction.
Velocity isn't always the same as speed.	The average velocity of an object may change, yet it is always the same.
m/s is the unit of speed.	m/s is the unit of velocity.

NCERT Physics Notes :

Frequently Asked Questions (FAQs)

1. A Car goes 120 metres in 5 seconds eastbound on a straight route, then 60 metres in 1 second westbound. Calculate the average speed and velocity.

Total Distance = 120 m + 60 m = 180 m

Total Displacement = 120 m – 60 m = 60 m, towards east.

Time Taken = 5s + 1s= 6 s

Average speed = Distance / time taken

= 180 m / 6 s

= 30 m/s

Average velocity = Displacement / time taken

= 60 m / 6 s

= 10 m/s

2. A runner runs around a rectangle track that is 50 metres long and 20 metres wide. He runs twice around the rectangle track before returning to the starting position. Calculate his average speed and velocity if he takes 100 seconds to complete a lap around

The circumference of the rectangle, which is the distance travelled in one round = 2(50 m) + 2(20 m) = 100 meters + 40 meters = 140 meters.

Runs around rectangle twice = 2(140 m) = 280 m

Total Distance = 280 meter.

Total Displacement = 0 (because the runner came back to initial point)

Average speed = the distance / time taken

= 280 m / 100 s

= 2.8 m/s

Average velocity = displacement / time taken

= 0 / 100 s

= 0.

3. A train travels a certain distance d in a straight line at a constant speed of 60 km/h, and then travels another distance equal to 2d in the same direction at a constant speed of 80 km/h. What is the train's average speed for the entire journey?

The time t1 to cover distance d at a speed of 60 km/h is by t1 = d / 60

The time t2 to cover distance 2d at a speed of 80 km/h is t2 = 2d / 80

Average Speed = distance/time

= (d + 2d) / (d/60) + (2d/80)

= 3d / (80d + 2d×60)/ (60×80)

= 3 d/(200d/4800)

= 3d (4800)/200d

= 72 km/h

4. Is average velocity the same as average speed?

The answer is no, average velocity is not the same as average speed. Because Average Speed = Total Distance/Total Time, this is the case.

Total displacement/Total time Equals Average Velocity

For example, when moving around a circular track, average speed and average velocity are different, just as displacement and distance are.

5. What do you mean by velocity?

Velocity is a vector quantity, meaning it has both a magnitude and a direction. It indicates how fast the body is moving or changing position. The velocity vector's direction is simple to determine. It moves in the same direction as the moving object. Even if the item is slowing down and the magnitude of velocity is decreasing, the object's direction will remain the same.