Topic 1.3: Position-Time Graphs
Name: _______________________________ Date: _______________
Before We Start: Yesterday's Recap
Yesterday we learned average velocity and average speed. Without looking back: what's the one key difference between what each formula uses (displacement vs. distance)?
Today's New Concepts
AP CED Alignment: Unit 1, Topic 1.C
Position-Time Graph
- A graph plotting an object's position on the vertical axis against time on the horizontal axis
- Shows the complete story of where an object was at every moment during the interval shown
- The SLOPE of the graph at any point equals the object's velocity at that point
- A straight-line section means constant velocity; a curved section means the velocity is changing (more on this in Week 2)
Reading the Graph
- Steeper slope → faster speed
- Flatter slope → slower speed
- Perfectly flat (zero slope) → object is at rest
- Negative slope → object is moving back toward its starting position
- A slope that changes sign (positive to negative, or vice versa) → the object reversed direction
Worked Example (plot these points yourself):
| Time (s) | Position (m) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 4 |
| 3 | 4 |
| 4 | 2 |
This data describes: moving away from the start at a steady pace for 2 seconds, stopping for 1 second, then moving back toward the start for the last second.
Keep This Sheet!
These sheets build into your semester study guide. Keep them in order in a binder or folder — you'll want to flip back through them before quizzes, unit tests, and when AP exam review starts in the spring.