Because speed is a rate, it depends on the time interval of motion. Like distance, speed is a scalar because it has a magnitude but not a direction. Speed is the rate at which an object changes its location. In this section we will look at time, speed, and velocity to expand our understanding of motion.Ī description of how fast or slow an object moves is its speed. Questions such as, “How long does a foot race take?” and “What was the runner’s speed?” cannot be answered without an understanding of other concepts. There is more to motion than distance and displacement. After they share their ideas, follow up with questions that deepen their thought process, such as: Why do you think that? What is an example? How might apply these terms to motion that you see every day? Speed Ask them to speculate about ways that speed is different from velocity. Explain to students that velocity, like displacement, is a vector quantity. Tell students that they will learn about these differences as they read the section. Explain that these words are often used interchangeably in everyday life, but their scientific definitions are different.

Then ask them if they have heard the word velocity used. Before students read the section, ask them to give examples of ways they have heard the word speed used.

In this section, students will apply what they have learned about distance and displacement to the concepts of speed and velocity.

Velocity definition physics science