Warm-up
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Get your green folder
Open to notebook paper and label it “
Speed and Motion Notes”
Make sure your have something to
write with
Write the formula for speed at the top
of your new page
If you are out of paper add three
more pages of notebook paper to your
brads
Objective 6.8- Changes in
Force and Motion
•Calculate average speed using
distance and time measurements
Speed and Motion
Measuring Motion Notes
Directions
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As you go through the PowerPoint
take notes.
Be sure to include the subtitles for
each different section so your notes
are organized and understandable.
Only copy “Question” slides if you
feel they will be helpful to you as
review.
Measuring Distance
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How you measure distance will
depend on what you are doing.
Meter – international unit for
measuring distance.
1.
2.
3.
4.
1 mm
km – long distances
m – medium distances
cm – small length
mm – tiny length
= 50 m
Measuring Time
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The time used will also depend on
what you are doing.
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Driving is usually hours (hr)
Walking is minutes (m)
Racing could be in seconds (s)
Calculating Speed
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divide the distance by the time to figure
out how far you traveled in a single unit
of time.
Speed = Distance
Time
Speed (S) =
distance traveled (d)
the amount of time it took (t).
S = d/t
What is speed?
When you calculate average speed,
you are figuring out how far you go
for ONE unit of time (1 second; 1
minute; 1 hour).
50 km
10 km
If travel 10 km/hr that means it takes you ONE HOUR to go TEN km.
Units for speed
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The units depend, but will always be
a distance unit over a time unit
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Ex. Cars: mi./h (miles per hour)
Jets: km/h (kilometers per hour)
Snails: cm/s (centimeters per second)
Falling objects: m/s (meters per second)
Calculating speed
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S = d/t
If I travel 100 kilometer in one hour
then I have a speed of…
100 km/h
If I travel 1 meter in 1 second then
I have a speed of….
1 m/s
Average speed
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Speed is usually NOT CONSTANT
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Ex. Cars stop and go regularly
Runners go slower uphill than downhill
Average speed =
total distance traveled/total time it took.
Calculating Average Speed
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It took me 1 hour to go 40 km on the
highway. Then it took me 2 more hours to
go 20 km using the streets.
Total Distance:
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Total Time:
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40 km + 20 km = 60 km
1 h + 2 h = 3 hr
Ave. Speed:
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total d/total t = 60 km/3 h = 20 km/h
Total _ Dist .
Ave. _ Speed 
Total _ time
Question
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I ran 1000 m in 3 minutes. Then
ran another 1000 m uphill in 7
minutes. What is my average
speed?
A) 100
m/min
TotalDist.
= 1000
m + 1000 m = 2000 m
 B) 2000 m/min
TotalTime
3 min + 7 min = 10 min
C) 10=m/min
 D) 200 m/min
Ave speed = total dist/total time =
 E) 20 m/min
2000m/10 min = 200 m/min = D
Graphing Speed:
Distance vs. Time Graphs
Denver
Phoenix
Distance (km)
Different Slopes
8
7
6
5
4
3
2
1
0
Slope = Rise/Run
= 1 km/1 hr
= 1 km/hr
Slope = Rise/Run
= 0 km/1 hr
= 0 km/hr
Rise = 2 km
Rise = 0 km
Run = 1 hr
Run = 1 hr
Slope = Rise/Run
= 2 km/1 hr
= 2 km/hr
Rise = 1 km
Run = 1 hr
1
2
3
4
Time (hr)
5
6
7
Graphing Motion:
Speed vs. Time Graphs
14
Speed (m/s)
12
10
8
6
4
2
0
0
1
2
3
4
5
6
Time (s)
1)Speed is increasing with time = accelerating
2)Line is straight = acceleration is constant
Graphing Motion:
Distance vs. Time Graphs
35
Distance (m)
30
25
20
15
10
5
0
0
1
2
3
4
5
Time (s)
1)On Distance vs. Time graphs a curved line means the
object is accelerating.
2)Curved line also means your speed is increasing.
Remember slope = speed.
Question:
35
Distance (m)
30
25
20
15
10
5
0
0
1
2
3
4
5
Time (s)
The black and red lines represent
a objects that are
accelerating. Black is going a greater distance each second, so
it must be speeding up. Red is going less each second, so
1)Which
line
represents an object that is
must
be slowing
down
accelerating?
Remember: in distance vs. time graphs:
curved line = accelerating, flat line = constant speed