Instantaneous Speed Formula

Define Instantaneous Speed

When we consider how fast or slow a body moves, we encounter the concept of velocity. We somehow associate body displacement with time spent in such displacement. This type of relationship is manifested as instantaneous speed. We will learn about instantaneous speed and the instantaneous speed formula in this chapter.


What is Speed?

Let’s know what speed is! Speed is defined as the rate at which an object's position changes over time. An object's speed can change as it moves. The speed of an object at a given point in time is referred to as its instantaneous speed. If the position is a function of time, the speed is determined by the change in position as time passes.

As the change in time becomes small, the instantaneous speed can be found. Finding the limit of the position function as the change in time approaches zero is required to calculate the instantaneous speed.


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Instantaneous Speed

It is the rate at which an object's distance changes with respect to time. The speed unit is metres per second (m/s).


Formula of Instantaneous Speed

Instantaneous speed (v) = distance/ time

v = limit as change in time approaches zero (change in position/ change in time)

The instantaneous speed is never less than or equal to zero. A scalar quantity is instantaneous speed. The instantaneous speed of uniform motion is constant. In other words, the magnitude of instantaneous velocity can be defined as at any given time is the magnitude of instantaneous speed at that time. As the time interval becomes very small, instantaneous speed becomes a limit of average speed.


How Do You Measure Instantaneous Speed?

Instantaneous Speed (v) = Distance/ Time


Instantaneous vs. Average

When a cop pulls you over for speeding, she measures your car's instantaneous speed, or the speed at a specific point in time as it speeds down the road. 'Instantaneous' is derived from the word 'instant,' which refers to a single moment.

This differs from your trip's average speed, which takes into account how long it took to complete the entire journey as well as the distance travelled. Be cautious: measuring average speed assumes you moved at roughly the same speed throughout the trip.

To compute instantaneous speed, divide a portion of the total distance travelled by time.


Difference Between Instantaneous Speed and Instantaneous Velocity


Instantaneous Speed

Instantaneous Velocity

The magnitude of instantaneous speed is known to be equal to the magnitude of instantaneous velocity.

The change in position that occurs at a small change in time is referred to as instantaneous velocity.

The quantity of instantaneous speed is a scalar quantity.

A vector quantity is instantaneous velocity.

FAQs (Frequently Asked Questions)

1. What is Instantaneous Speed Class 11?

Answer: The instantaneous velocity of an object describes how fast it moves at different points in time within a given time interval. The magnitude of velocity is instantaneous speed. The magnitude of the instantaneous velocity at that instant is equal to the instantaneous speed.

2. How Do I Calculate Instantaneous Speed?

Answer: The absolute value of instantaneous velocity is used to calculate instantaneous speed, which is always positive. The average speed is calculated by dividing the total distance travelled by the time elapsed. The slope of a position-versus-time graph at a given time represents instantaneous velocity at that point.

3. What is Instantaneous Speed of a Vehicle?

Answer: What you see on a car's speedometer is the speed at that particular instant or moment – the instantaneous speed. It's the current speed. Measuring the rate of rotation of the wheels is one method for determining this instantaneous speed.