1. Distance & Displacement

2. Distance Distance (d) – how far an object travels
Does not depend on direction
Imagine an ant crawling along a ruler
What distance did the ant travel?
d = 3 cm cm 1 2 3 4 5 6 7 8 9 10

3. Distance
Imagine our ant crawling again, now what distance did the ant crawl?
d = 3 cm
Did the direction change the answer? No cm 1 2 3 4 5 6 7 8 9 10

4. Distance Let’s follow the ant again
What distance did the ant travel this time?
d = 7 cm cm 1 2 3 4 5 6 7 8 9 10

5. Displacement
Displacement (Δx) – shortest path between point A (initial) and point B (final)
Does depend on direction
(need + and -, or N, S, W, E)

6. Displacement Let’s visit the ant again What is the ant’s distance?
3 cm
What is the ant’s displacement?
+3 cm (the positive means forward direction) cm 1 2 3 4 5 6 7 8 9 10 + -

7. Displacement Distance? Displacement?
Find the ant’s distance and displacement
Distance?
3 cm
Displacement?
-3 cm (the negative means backward direction) cm 1 2 3 4 5 6 7 8 9 10 + -

8. Displacement Distance? Displacement?
Find the ant’s distance and displacement
Distance?
7 cm
Displacement?
+3 cm cm 1 2 3 4 5 6 7 8 9 10 + -

9. Distance vs. Displacement
An athlete runs around a track three times that is a 100 meters long, then stops. What is the athlete’s distance and displacement?
Distance =
Displacement =
300 m
0 m

10. Example
What is the distance traveled?
d = 17 m
8 m
6 m
2 m
1 m

11. Example
What is the displacement?
8 m
6 m
2 m
1 m

12. Example
A turtle crawls 5 m North, then 3 m East, and then 2 m South. What is his distance traveled and displacement?
5 m
3 m
2 m
Distance =
Displacement = ?
10 m