Describing motion with Graphs
Position vs. Time Graphs
• x-axis: Time
• y-axis: Position
• slope = velocity (slope = “rise” / “run”)
• horizontal line: at rest
• straight line: constant velocity
– positive slope = positive velocity
– negative slope = negative velocity
• curved line: acceleration
Position vs. Time Graphs
Position vs. Time Position vs. Time
10 50
Position (m)
8 40
Position (m)
6 30
4
20
2
10
0
0
0 1 2 3 4 5
0 1 2 3 4 5
Time (s)
Time (s)
Position vs. Time Position vs. Time
50 50
40
Position (m)
Position (m) 30
30
20 10
10
-10 0 1 2 3 4 5
0
0 1 2 3 4 5 -30
Time (s) Time (s)
Determine the velocity from each of the above graphs.
Position vs. Time Graphs
Position vs. Time
125
Position (m)
100
75
50
25
0
0 1 2 3 4 5
Time (s)
What is happening to the velocity of an object whose position-time
graph looks like this? What is this object doing?
Velocity vs. Time Graphs
• x-axis: Time
• y-axis: velocity
• slope = acceleration (slope = “rise” /
“run”)
• horizontal line: constant velocity
• straight line: uniform acceleration
– positive slope = positive acceleration
– negative slope = negative acceleration
(deceleration)
• curved line: non-uniform acceleration
Velocity vs. Time Graphs
Velocity vs. Time Velocity vs. Time
10 50
Velocity (m/s)
8
Velocity (m/s)
40
6 30
4 20
2
10
0
0
0 1 2 3 4 5
0 1 2 3 4 5
Time (s)
Time (s)
Velocity vs. Time Velocity vs. Time
50 50
Velocity (m/s)
40
Velocity (m/s)
30
30
20 10
10
-10 0 1 2 3 4 5
0
0 1 2 3 4 5 -30
Time (s) Time (s)
Determine the acceleration from each of the above graphs.
Velocity vs. Time Graphs
Velocity vs. Time
125
Velocity (m/s)
100
75
50
25
0
0 1 2 3 4 5
Time (s)
What is happening to the acceleration of an object whose velocity-
time graph looks like this?