1. Objective
SWBAT use distance-time graphs to determine an object’s speed.

2. “Service to others is the rent you pay for your room here on Earth
“Service to others is the rent you pay for your room here on Earth.” —Muhammad Ali

3. Distance-Time Graph

4. Velocity Velocity is speed in a specific direction.
When moving forward, velocity is positive.
When moving backward, velocity is negative.

5. Interpreting Distance-Time Graphs
From point A to point B…
Distance traveled = 8 m – 0 m = 8 m
Time = 4 s – 0 s = 4 s
 Object is moving forward at constant speed of 2 m/s

6. Interpreting Distance-Time Graphs
From point B to point C…
d = 8 m – 8 m = 0 m
t = 7 s – 4 s = 3 s
 Object is not moving.

7. Interpreting Distance-Time Graphs
From point C to point D…
d = 0 m – 8 m = — 8 m
t = 10 s – 7 s = 3 s
 Object is moving backwards.

8. Note!
The slope of a line segment = speed of the object during that time.

9. Check For Understanding
When the line on a distance-time graph has a negative slope, the object is…
Moving forward.
Moving backward.
Not moving.

10. What was the speed from 0 seconds to 5 seconds?
During which time interval was this person moving the fastest?
During which time interval was this person not moving?

11. Check For Understanding
When the line on a distance-time graph is flat, the object is…
Moving forward.
Moving backward.
Not moving.

12. What is Student A’s speed?
What is Student B’s speed?
Who is moving faster?

13. Check For Understanding
When the line on a distance-time graph has a positive slope, the object is…
Moving forward.
Moving backward.
Not moving.

14. Challenge Question
Are either of these students ever accelerating? How can you tell?

15. Challenge Question
No. The slope of each line does not change, so their speeds are staying the same the entire time. The speeds do not increase or decrease.

16. What acceleration would look like…