Difference Between Average Velocity and Instantaneous Velocity (With Table)

The velocity of any object is defined as the rate of change in the position of the object concerning time along with its direction. Average velocity is the displacement of the object to time, it is also called the change in the location of the object divided by the time frame. Instantaneous velocity is the rate of displacement or rate of change in position to time at a particular point.

Average Velocity vs Instantaneous Velocity

The difference between Average Velocity and Instantaneous Velocity is that they differ in their formula, their approach towards acceleration, and their quantities. They have various similarities as well as differences. Both average velocity and instantaneous velocity are vector quantities and have the same SI units.

Average Velocity is the ratio of displacement to the time taken for that displacement to occur. It is a vector quantity. The only difference between an average speed and average velocity is that average speed is calculated by dividing the rate of distance traveled by time, whereas average velocity is calculated by dividing the rate of displacement by time elapsed.

Instantaneous velocity is defined as velocity or displacement at an instant of time. Average velocity and instantaneous velocity will approach unity when the velocity is constant or the acceleration is zero. It is a vector quantity and its SI unit is meter per second which is the same as average velocity.

Comparison Table Between Average Velocity and Instantaneous Velocity

Parameters of ComparisonAverage VelocityInstantaneous Velocity
Definition Average velocity is defined as the rate of displacement or change in the location of the object to time. Instantaneous velocity is defined as the displacement as an instant of time.
SI Unitmeter per second is the SI unit of average velocity.meter per second is the SI unit of instantaneous velocity.
QuantityAverage velocity is a vector quantity, as it includes both magnitude and direction.Instantaneous velocity is also a vector quantity.
FormulaAverage velocity is calculated by dividing the rate of displacement by time elapsed. Instantaneous velocity is calculated by dividing displacement by time at that instant or particular point of time.
SimilarityWhen velocity is constant both average velocity and instantaneous velocity are equal.When acceleration is zero both average velocity and instantaneous velocity are equal.

What is Average Velocity?

Average velocity is a quantity that is proposed concerning time. It is the rate of change in location or displacement at a particular period between the positions of the object being displaced. It is calculated as the rate of displacement divided by time elapsed. It is a vector quantity. Its SI unit is a meter per second.

Average velocity included both magnitude and direction, unlike average speed which includes only the magnitude. The varying velocity of an object helps in determining the overall journey of the object using average velocity. It can be derived as total displacement divided by the total time taken.

Average velocity can be found using a total velocity divided by time. When the object has varying velocity throughout its journey then average velocity can be calculated as the sum of all its displacements divided by the sum of time taken. It is also called Average Linear Velocity.

When an object is moving in a straight line towards a particular direction, its average velocity can be found using average linear velocity, whereas when an object revolves around a circular direction and reaches a particular point, it is called Average Angular Velocity.

What is Instantaneous Velocity?

Instantaneous velocity is the quantity that describes the speed of an object along with its direction between two points. It is the velocity between two points at an instant of time. It has a limit that the time between the two pints or the time elapsed during the displacement approaches zero.

Instantaneous velocity has the SI unit as a meter per second or CGS unit as length per time. It is a vector quantity that describes both the magnitude and speed of an object with time. Instantaneous velocity can be negative or positive, whereas Instantaneous speed is always positive which is found using instantaneous velocity.

Instantaneous velocity can be expressed using graphs and slopes. It is equal to average velocity when either the velocity is constant over time or the acceleration is zero at that instant of time. It is the velocity at an instant of time, a graph that represents velocity at every instant of time is also known as instantaneous velocity.

A graph plotted with the position of the location of the object versus the time frame, such that the slope thus occurred is the tangent line and thus the resulting velocity is said to be Instantaneous velocity. Instantaneous velocity and instantaneous speed are the same except they differ in their vector and scalar quantities.

Main Differences Between Average Velocity and Instantaneous Velocity

  1. Average velocity is the rate of displacement divided by time elapsed, whereas Instantaneous velocity is the velocity at an instant of a time frame of an object.
  2. Average velocity is equal to instantaneous velocity when the time approaches zero, whereas Instantaneous velocity is equal to average velocity when the acceleration is zero.
  3. Average velocity is a vector quantity. Instantaneous velocity is also a vector quantity.
  4. Average velocity has a unit as a meter per second, whereas Instantaneous velocity has a unit as length per time.
  5. Average velocity can be plotted in a graph, whereas Instantaneous velocity can be derived from the plot of an average velocity over various periods.

Conclusion

Average velocity is the velocity of an object between two points at a particular time. Instantaneous velocity is the displacement between two points of an object at an instant of time. They have the same quantities as vectors and the same units. Both Average velocity and Instantaneous velocity are plotted and explained through graphs and slopes.

Average Velocity can be also known as Average Linear velocity when the object moves in a linear direction and Average Angular Velocity if the object moves in a circular path, whereas such variations aren’t present in Instantaneous velocity. Instantaneous speed can be obtained using Instantaneous velocity.

References

  1. https://www.sciencedirect.com/science/article/pii/0009250970850126
  2. https://www.jstor.org/stable/30043691
x
2D vs 3D