Motion analysis
What is average velocity?
Average velocity describes how quickly an object changes position over an elapsed time interval. It is a vector quantity, so its sign represents direction.
Formula
Average velocity formula
Average velocityv̄ = Δx ÷ Δt
- v̄ is average velocity.
- Δx is displacement.
- Δt is elapsed time.
Worked example
Calculate velocity from displacement
- Displacement is 120 metres.
- Elapsed time is 10 seconds.
- Apply v̄ = 120 ÷ 10.
- Average velocity is 12 m/s.
Important distinction
Average velocity versus average speed
Average velocity uses net displacement, while average speed uses total distance. An object can return to its starting position and have zero average velocity even though its average speed is greater than zero.
Direction
Why average velocity can be negative
The sign depends on the coordinate direction selected for the motion. A negative value indicates that net displacement occurred in the negative direction.
Applications
Where average velocity is used
- Linear motion experiments.
- Position-time graph analysis.
- Vehicle and transport studies.
- Projectile and free-fall problems.
- Introductory kinematics calculations.
Related tools
Continue your motion analysis
Use the Acceleration Calculator to calculate changes in velocity over time.
Use the Rate of Change Calculator for general change-over-time analysis.
Interpretation limits
Assumptions and limitations
Average velocity is based on net displacement divided by elapsed time. It does not describe the complete path, instantaneous velocity, acceleration, or variations that occur during the interval.
Direction must be represented consistently with signs or coordinates. A round trip can have zero average velocity even when the object travelled a substantial total distance.
Questions and answers
Average velocity FAQ
What formula does the average velocity calculator use?
It uses average velocity equals displacement divided by elapsed time: v̄ = Δx ÷ Δt.
What is the difference between average velocity and average speed?
Average velocity uses displacement and includes direction, while average speed uses total distance travelled and has no direction.
Can average velocity be negative?
Yes. A negative average velocity means the net displacement is in the selected negative direction.
Can average velocity be zero?
Yes. Average velocity is zero when final position equals initial position, even if the object travelled some distance.