Instantaneous speed

Definition

Instantaneous speed is the magnitude of the instantaneous velocity. It represents how fast an object is moving at a specific moment in time.

5 Must Know Facts For Your Next Test

1. Instantaneous speed is a scalar quantity, meaning it has only magnitude and no direction.
2. It can be determined by taking the limit of the average speed as the time interval approaches zero.
3. Instantaneous speed is always non-negative since it measures the absolute value of velocity.
4. The unit of instantaneous speed in the SI system is meters per second (m/s).
5. In uniform motion, instantaneous speed equals average speed, but in non-uniform motion, they may differ.

Review Questions

• How does instantaneous speed differ from average speed?
• Why is instantaneous speed considered a scalar quantity?
• What happens to the instantaneous speed if an object maintains a uniform motion?

Related terms

Instantaneous Velocity:

The rate at which an object's position changes with respect to time at a specific instant; it includes both magnitude and direction.

Average Speed: The total distance traveled divided by the total time taken; it gives an overall measure of how fast something moves over a period.

Uniform Motion:

Motion at a constant speed in a straight line, where both instantaneous and average speeds are equal.