1. 2.3 Position-Time Graphs Essential Questions
What information do position-time graphs provide?
How can you use a position-time graph to interpret an object’s position or displacement?
What are the purposes of equivalent representations of an object’s motion?
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Position-Time Graphs

2. 2.3 Position-Time Graph Vocabulary Review New Intersection
instantaneous position
Vocabulary
Position-Time Graphs
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3. 2.3 Position-Time Graphs 1. Finding Positions
a. In a position-time graph, the time data is plotted on a horizontal axis and the position data is plotted on a vertical axis.
b. Graphs of an object’s position and time contain useful information about an object’s position at various times.
c. The symbol x represents the instantaneous position of the object—the position at a particular instant.
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Position-Time Graphs

4. 2.3 Position-Time Graphs Example 1 Problem 1 When did the runner
reach 20 m beyond the
starting point?
Where was she after
4.5 s?

5. 2.3 Position-Time Graph Practice Problem 11
The graph in Figure 12 represents
the motion of a car moving along a
straight highway.
Describe in words the car’s motion.
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Position-Time Graphs

6. 2.3 Position-Time Graph Practice Problem 12
Draw a particle model motion
diagram that corresponds to the
graph.

7. 2.3 Position-Time Graph Practice Problem 13
Answer the questions about the car’s
motion. Assume that the positive
x-direction is east of the origin and the
negative x-direction is west of the origin.
At what time was the car’s position
25.0 m east of the origin?
Where was the car at time t = 1.0 s?
What was the displacement of the car
between time t = 1.0 s and t = 3.0 s?

8. 2.3 Position-Time Graph Practice Problem 14
The graph in Figure 13 represents the motion of
two pedestrians who are walking along a straight
sidewalk in a city. Describe in words the motion
of the pedestrians. Assume that the positive
direction is east of the origin.

9. 2.3 Position-Time Graph 2. Multiple Objects on a Position-Time Graph
a. The motion of more than one object can be graphed on a single position-time graph.
b. When two lines intersect, the objects are in the same place at the same time.
Position-Time Graphs
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10. 2.3 Position-Time Graph Practice Problem 20
Juanita goes for a walk. Later her
friend Heather starts to walk after
her. Their motions are represented
by the position-time graph in Figure 15.
How long had Juanita been walking
when Heather started her walk?
Will Heather catch up to Juanita?
How can you tell?
What was Juanita’s position at
t = 0.2 hr?
At what time was Heather 5.0 km
from the start?

11. 2.3 Position-Time Graph
Assignment: p. 45 #21-25 p. 55 #59, 60, 65, 66 Need graph paper

12. 2.3 Position-Time Graph