Student Exploration: Distance-Time and Velocity-Time Graphs
[NOTE TO TEACHERS AND STUDENTS: This lesson was designed as a follow-up to the Distance-Time Graphs Gizmo™. We recommend you complete that activity before this one.]
Vocabulary: displacement, distance traveled, slope, speed, velocity
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Dora runs one lap around the track, finishing where she started. Clark runs a 100-meter dash along the straight side of the track.
Which runner traveled a greater distance? Which runner had a greater change in position, start to finish? Gizmo Warm-upThe Distance-Time Graphs Gizmo shows a dynamic graph of the position of a runner over time. The Distance-Time and Velocity-Time Graphs Gizmo includes that same graph and adds two new ones: a velocity vs. time graph and a distance traveled vs. time graph. The graph shown below (and in the Gizmo) shows a runner’s position (or distance from the starting line) over time. This is most commonly called a position-time graph.
Check that the Number of Points is 2. Turn on Show graph and Show animation for both Runner 1 and Runner 2. Drag the points to create the graph shown to the right.Runner 1’s line (the red one) should have endpoints at (0, 0) and (4, 40).Runner 2’s line (the blue one) should have endpoints at (0, 40) and (4, 20). Click the green Start button on the stopwatch. Watch the two runners carefully. In what two ways are the runners’ motions different?.Activity A:
Get the Gizmo ready:
Click the red Reset button on the stopwatch.
Change the Number of Points to 5.
Turn off Show graph and Show animationfor Runner 2.
Speed is a measure of how fast an object moves, regardless of direction. Speed can never be negative. Velocity describes both speed and direction, and can be positive or negative.