Graphs of Motion:
P-T, V-T, and A-T
SEPTEMBER 12-15, 2014
What do we already know about
graphing motion?
We know how to draw and interpret position vs time (P-T) graphs
 Straight
lines = Constant velocity / NO acceleration
Positive slope
v=+
Negative slope:
v=-
Zero slope:
v=0
What do we already know about
graphing motion?
We know how to draw and interpret position vs time (P-T) graphs
 Curved
v=+
a=+
lines = Accelerated motion
v=a=+
v=+
a=-
v=a=-
Your motion graph
Take a minute a look at your graph of motion … do you still think it is
correct?
If not, fix it!
V-T graphs
What do you think these mean?
Think, Pair, Share
Rules for V-T graphs
• Horizontal lines: a = 0
v = +, a = 0
v = +, a = +
v = +, a = -
• Positive slopes: a = +
• Negative slopes: a = • Lines above the x
axis: v = +
v = -, a = 0
v = -, a = +
v = -, a = -
• Lines below the x
axis: v = -
Test your Understanding
Think about your answer, wait until I tell you, then show me the
answer by holding up the correct number of fingers.
Which runner(s) have
the greatest speed?
1) A
2) C
3) B & D
4) E
Test your Understanding
Think about your answer, wait until I tell you, then show me the
answer by holding up the correct number of fingers.
Which runners are
slowing down?
1) A
2) C
3) B & D
4) E
5) None of them
Test your Understanding
Think about your answer, wait until I tell you, then show me the
answer by holding up the correct number of fingers.
Which runners are
changing direction?
1) A
2) C
3) D
4) E
5) None of them
You Do: Interpreting V-T Graphs
Use the graph of the motion of a
toy train, below, to answer the
questions.
1) When is the train’s speed constant?
From B-C, from D-E, and from F-G
2) When was the train’s velocity
positive?
Always!
3) When is the train’s acceleration
positive?
From A-B, from C-D, and from G-H
4) When did the train slow down?
From E-F
Putting it all together:
Creating V-T and A-T graphs
To create a V-T graph, I will first
determine the v and a of each
segment of the graph.
v=+
a=-
v=0
a=0
v=+
a=0
v=0
a=0
v=+
a=+
v=+
a=+
v=+
a=0
v=a=0
v=a=0
v=+
a=-
Putting it all
together:
Creating V-T and
A-T graphs
v=+
a=-
v=0
a=0
a=+
a=0
a=-
v=+
a=0
v=0
a=0
v=+
a=+
v=+
a=+
v=+
a=0
v=a=0
v=a=0
v=+
a=-
Creating V-T and A-T graphs:
Testing your understanding
Study the problem, then when I say, show “thumbs up” or “thumbs down” to indicate
whether the graph has been drawn correctly.
Creating V-T and A-T graphs:
Testing your understanding
Study the problem, then when I say, show “thumbs up” or “thumbs down” to indicate
whether the graph has been drawn correctly.
Creating V-T and A-T graphs:
You Do
Draw the corresponding V-T and A-T
Homework
HW sheet, HW Quiz next class
Closure
What were our objectives & how did we meet them?
How did what we did today reflect our unit goal?
How did we utilize our LP trait of communicators?
What was our primary ‘way of knowing’ used today?
Exit Ticket
Complete motion graphs classwork sheet