What is the difference between speed and velocity?

Expert Answers
trophyhunter1 eNotes educator| Certified Educator

The speed of an object can be calculated if you know the distance that was traveled divided by the time it took to get there. Units can be miles per hour or kilometer per hour for example. However, velocity is the measurement of the rate and direction of change of a given object in motion. For instance, if a person is running 2 miles per hour, that is her speed. However, if she is running 2 miles per hour southwest, that is her velocity.

sultlete | Student

In expansion to the above responses (and just to make clarification), Speed is known as a Scalar and is dependant only on Magnitude (in m/s using SI units, not m/s^2, that is accelaration, its different), but doesn't necessarily use symbol (a) because (a) is also used as universal constant for acceleration. Speed can be determined by the equation S=d/t; i.e, Speed equals the distance over time.

Velocity on the other hand is a Vector which relies on both Magnitude and direction.
As an example to differentiate the two, speed would be 100 km/h, whilst velocity would be 100 km/h North.
The direction in velocity is directly linked to displacement, or how far from where you originally started. So, if you were to travel 50 kilometres one way (east) your displacement would be 50 kilometers East, but if you were to travel 50 kilometres one way and 50 kilometers back, your displacement would be 0 kilometres because you would be back in your original position (this is important in relative motion)
Velocity is usually measured in m/s with direction, but can also use m/s^2 when using velocity to determine acceleration because Acceration (a)= [final velocity in m/s(Vf) - initial velocity in m/s (Vi)] / change in time in seconds(Delta t). After substituting, you get an acceleration in m/s^2.

Make sense? Message if you have any more queries.

shizza123 | Student

Speed: Rapidity of movement or action. Velocity: The speed of something in a given direction.


lovelysarkar | Student

difference between speed nd velocity are as folows:-


  • the distance travelled by a movin object in one second
  • it is a scalar quantity
  • it tells does not about direction
  • the speed is always positive
  • in one round in a circular path,the average speed is not zero


  • the distance travelled by a moving body in one second in a particular direction
  • it is a vector quantity
  • it tells us about direction too
  • the velocity can be positive or negetive
  • in a round in a circular path the velocity of tha moving object is zero
janeausten11 | Student

Speed (a) -> m/s^2 (meters per second squared)

Velocity (v) -> m/s (meters per second)

sk8danaj | Student

the difference between speed and velocity is there is a direction assosiated with velocity. speed is distance tracelled per unit of time whilst velocity is distance travelled per unit of time in a given direction.

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