# What is the difference between AVERAGE and INSTANT speed?explain briefly

pacorz | High School Teacher | (Level 3) Educator

Posted on

Instantaneous speed is the exact speed that a body is moving at, at a given instant in time. It is a true measure of the body's motion for that point in time.

An average speed tells you how much distance a body covers during a certain time span, but it does not tell you much about the actual motion that occurred.

For example, a person is driving and they look down at their speedometer and see that they are traveling at 120 km/hr. That is an instantaneous speed. It tells us that, at least at one point during the trip, they were driving quite fast.

Now suppose the same person drives at 120 km/hr for one hour, then hits heavy traffic and drives at 20 km/ hr for another hour. The average speed for this trip would be 70 km/hr.  If you only know their average speed, you would think that the person is quite a slow driver, but that would not be true.

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kavya--kammana | Student, Grade 12 | (Level 1) Valedictorian

Posted on

Average speed is the speed averaged over a span of time. Usually the total distance covered divided by the total time span.

Instantaneous speed would be the speed any any given instant within that span of time, measured with a realtime speedometer.