1. Graphing Speed
Moving from Home

2. Graphing Variables – Recall
The Variables
The Graph
Dependent Variable
The dependent variable goes on the y-axis
The independent variable goes on the x-axis
Independent Variable

3. The Speed Graph Setup Distance is the dependent variable
The Variables
The Graph
Distance is the dependent variable
Time is the independent variable
Graph setup = Formula
Distance d
sp = t
Time

4. Speed & Slope (quick version)
Speed (d/t)= slope on a speed graph (rise/run)
Speed
Steeper slope = faster speed
Distance
Changing slope = changing speed
Zero slope = 0 speed
Lower slope = slower speed
Time

5. Speed Graphs & Slope (more)
dist t
Positive (+) slope
Forward motion (away from start) t
dist
Negative (-) slope
Backward motion (toward start) t
dist
Zero (0) slope (flat line)
No motion (speed = 0)

6. Speed Graphs & Slope (still more)
dist t
dist t
Straight lines
Constant speed (speed doesn’t change)
dist t
Lines curving upward
Acceleration (speeding up)
Slope is getting steeper (↑speed)
Lines curving to flat
Deceleration (slowing down)
Slope is getting lower (flatter)
dist t

7. Calculating Speed from Slope
rise
run
Speed =
distance
time
Rise–change in the graph on the vertical axis (Distance)
Run–change in the graph on the horizontal axis (Time)

8. Answers to Sample Questions
What is the speed of the object from 0 – 3 s?
What is the speed of the object from 3 – 6 s?
What is the speed of the object from 6 – 8 s?
Distance (rise)
( 6 – 0 m)
6 m
Speed (slope) = = = =
2 m/s
Time (run)
( 3 – 0 s)
3 s
Distance (rise)
( 6 – 6 m)
0 m
Speed (slope) = = = =
0 m/s
Time (run)
( 6 – 3 s)
3 s
Distance (rise)
(0 – 6 m)
6 m
Speed (slope) = = = =
2 m/s
Time (run)
(8 – 6 s)
2 s