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Graphs of Motion: P-T, V-T, and A-TSEPTEMBER 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 =
Positive slope Negative slope: Zero slope:
Constant velocity / NO acceleration
v = + v = - v = 0
What do we already know about graphing motion?
We know how to draw and interpret position vs time (P-T) graphs Curved lines =
Accelerated motion
v = +a = +
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?
v = +, a = 0 v = +, a = + v = +, a = -
v = -, a = 0 v = -, a = -v = -, a = +
Think, Pair, ShareRules for V-T graphs• Horizontal lines: • Positive slopes:
• Negative slopes:
• Lines above the x axis:
• Lines below the x axis:
a = 0a = +
a = -
v = +
v = -
Test your UnderstandingThink 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)A2)C3)B & D4)E
How do
you know?
Test your UnderstandingThink 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)A2)C3)B & D4)E5)None of them
How do
you know?
Test your UnderstandingThink 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)A2)C3)D4)E5)None of them
How do
you know?
You Do: Interpreting V-T GraphsUse the graph of the motion of a toy train, below, to answer the questions. 1)When is the train’s speed constant?
2)When was the train’s velocity positive?
3)When is the train’s acceleration positive?
4)When did the train slow down?
From B-C, from D-E, and from F-G
From A-B, from C-D, and from G-H
From E-F
Always!
Putting it all together: Creating V-T and A-T graphsTo create a V-T graph, I will first determine the v and a of each segment of the graph.
v = +a = 0
v = 0a = 0
v = -a = 0
v = +a = +
v = +a = -
v = +a = 0
v = 0a = 0
v = -a = 0
v = +a = +
v = +a = -
Putting it all together: Creating V-T and A-T graphs
v = +a = 0
v = 0a = 0
v = -a = 0
v = +a = +
v = +a = -
v = +a = 0
v = 0a = 0
v = -a = 0
v = +a = +
v = +a = -
a = 0a = +
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
ClosureWhat 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 TicketComplete motion graphs classwork sheet
