Source: Speed Limit Sign,
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Speed is a type of rate. Have you ever been asked to define the term speed? If so, you would probably answer, "how fast an object is moving." More specifically, speed is the distance an object travels in a given amount of time.

If the speed of an object does not change during its motion, the object is traveling at a constant speed. Most objects do not move at a constant speed. Most moving objects change speed many times while in motion. The average speed of an object tells you the average rate at which it covers distance.

Let's pretend you went on a walk through your neighborhood. You walk 5 km to the neighborhood park, and it takes you 45 minutes. You stop and rest for 25 minutes at the park, and then you walk 5 km back home. It takes you 50 minutes to walk back home from the park.

What was your average speed? In the next section you will learn how to calculate average speed.