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Thinking About The Question

When am I changing velocity or accelerating?

Imagine you are a marine biologist and you want to track the movements of whales in the ocean. What information about the movements of the whale would you want to know? Where is the whale? What is the whale's position? How fast is the whale traveling? How does the motion of the whale relate to other moving objects? Think about other professions. A racecar driver wants to know how fast they can reach a certain speed? A baseball player wants to know how fast a pitcher throws a fastball. What information about the movements of other objects in motion are you interested in finding out about? Discuss these questions with your team and write down some of your examples and questions to share with the class.

There is technology that helps scientists to answer questions about motion. For example, many ships use sonar to find objects at the bottom of the ocean and to view objects, like whales, as the ship draws near them. A motion sensor (also called an ultrasonic detector) uses technology for a similar purpose. Refer to Technical Hints to learn how a motion sensor works. Observe the following graph. This graph is the movement of a car on a 4 meter straight race track as displayed by a motion sensor. What facts can you determine from the graph below about the motion of the car?

This graph shows the movement of a car on a 4 meter straight race track as displayed by a motion sensor. What facts can you determine from the graph about the motion of the car?