Motion Diagrams
Sometimes we
want to look at
an object at one
point in time –
that means its
position (x).
Example 1:
A stationary pool ball on a surface.
• Any object that is at
rest for an instant,
occupies only a
single position and is
indicated with a
single dot:
• If the object stands still for several beats or
seconds, indicate it with several dots one
above another:
This object is not moving for
3 beats of the Metronome or
2 time intervals.
• If the object stands still for a long time place
a circle around one dot:
Motion Diagrams of Moving Objects
Sometimes we want to observe
the movement of objects. We
call this change in position rx.
rx = Xf - Xi
Example 2: How does a motion diagram show a
skateboarder moving down a sidewalk at a
constant speed?
1st There is equal distance between each point.
2nd This makes each arrow the same length.
3rd The arrows point in the direction that the skater
is moving.
What will the motion
diagram look like for this
X vs t graph?
Draw it above the line
provided!
Example 3: The Tortoise and the
Jack-a-lope were having a race.
Make an x-t graph of the motion diagram.
Since the arrows for the rabbit are 4
times longer than those of the tortoise,
the rabbit runs four times faster than
the tortoise.
Dot Alignment
What does it mean when 2 dots line up in
the same position on the x axis?
Dot Alignment
It means that the Jackalope reached that
position after one time interval, and the
tortoise reached the same position after 4
time intervals have passed.
Written descriptions of Motion Diagrams include
some or all of the following:
1)
2)
3)
4)
5)
6)
7)
Starting Position (Initial Position)
Ending Position (Final Position)
Distance Traveled
Number of Intervals (seconds, min., hours)
Number of Beats (metronome)
Velocity or Speed Comparison
Direction of Motion
What info does
this diagram
give us?
Give a Written Description
What information can we get from this this Diagram?
Give a Written Description
What info does this diagram give us?
0
-50 meters
Give a Written Description
30 m
What info does
this diagram
give us?
Give a Verbal Description
Compare the Motion of A & B
with a written description and a
Motion Diagram
A.
30 meters
B.
25 meters
Brad’s Car
Mike’s Car
a) Brad and Mike decide to race their cars.
They start the race at Mike’s house, which
is 200m down the street from Brad’s
house. Draw a motion diagram for the two
cars when they are both at the starting
line, ready to begin the race.
X
Brad’s Car
Mike’s Car
b) Mike drives his car with a constant speed
of 20 m/s and Brad drives his car at a
constant speed of 25 m/s. Draw a motion
diagram for both cars when they are
moving toward Brad’s house (X).
X
Brad’s Car
Mike’s Car
c) When Brad reaches his house he does
not wait for Mike, but turns around and
drives back to Mike’s house. Draw a
motion diagram for the case where Brad
drives toward Mike’s house, while Mike is
still driving toward Brad’s house.
X
Brad’s Car
Mike’s Car
c) When Brad reaches his house he does
not wait for Mike, but turns around and
drives back to Mike’s house. Draw a
motion diagram for the case where Brad
drives toward Mike’s house, while Mike is
still driving toward Brad’s house.
X
A dog sees a squirrel. From the motion
diagram below, tell what movements
the dog’s uses to try to catch the
squirrel.
5
10
15
20
25 meters
Make an x vs t graph of Angela’s Motion
Make an x vs t graph of Angela’s Motion
Draw a motion diagram of the graph below.
t (hour)
v=
3000 -1000
250
Motion Diagram:
=250 m / min
12 - 4
m 60 min 1 km
min 1 hour 1000 m
=15 km / h
• Calculate the slope of the line.
• Make a motion diagram of the graph.
Draw a motion diagram for these
two objects (A & B).