Key Concepts
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When is an object in motion?
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How do you know an object’s
speed and velocity?
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How can you graph motion?
 Motion
 Average
speed
 Reference point  Instantaneous
speed
 International
system of units  Velocity
 Meter
 slope
 Speed
Pace
Distance
Slow
5m
Slow
Medium
5s
5m
Medium
Fast
Fast
Time
5s
5m
5s
Q: What is the relationship
between the distance you walk,
the time it takes you to walk, and
your walking speed?
A: The faster you walk, the less time it takes to
move a certain distance. The faster you walk,
the farther you will travel in a given time. If you
walk a longer distance in a given amount of
time, you are walking faster.
Q: How do you know if an object is moving?
A: An object is in motion if its distance from
another object is changing.
Q:What is a reference point?
A:A reference point is a place or object used for
comparison to determine if something is in
motion.
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What kinds of objects make good reference
points?
What happens if your reference point is
moving?
Come up with some examples of moving
reference points
Examples: 2 buses or trains moving past each
other.
Q: Are you moving as you sit and read a book?
A: It depends on your reference point
If your chair is your reference point – No
If the sun is your reference point – Yes
(at 30km/s)
Q: Why might ancient astronomers have been
convinced that the sun, planets, and stars
revolve around the Earth?
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Calculating Speed - Speed is a type of rate

Speed of an object is the distance the object travels per
unit of time
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The speed equation:
Speed = Distance
Time
Examples:
1. A cyclist traveling 30 km in 1 hr has a speed of 30
km/hr
2. An ant that moves 2 cm in 1 second has a speed of
2cm/s
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Average Speed - divide the total distance by the total time
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Example: A cyclist travels 32 km during the first 2 hours, then 13
km the next hour.
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The average speed is total distance divided by total time
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Total distance = 32km +13km = 45 km
Total time = 2h + 1 h
=3h
Average speed = 45km = 15km/h
3h
Instantaneous speed - rate at which an object is moving at a
given instant in time
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1. It takes Dave 15 minutes to walks 1mile to
the bus stop. He then travels for 15 minutes
on the bus and travels 10 miles. Finally he
walks 1 mile that takes him 15 minutes to his
college class. What is Dave’s average speed?
Total distance = 1 + 10 +1 =12 miles
Total Time = 15min +15 min. + 15 min. =
45min.
S=d/t = 12mile/45 min = .27 mile/min
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What system do we use in science to
measure?
What is the SI unit of length?
What other SI units are used to measure
length?
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Use a conversion factor to convert from one
metric unit to another.
Conversion factors are fractions in which the
numerator and denominator represent equal
amounts in different units.
Ex: 1000mm
1m
Ex. How many millimeters are in 14.5 m
14.5m X 1000mm = 14.5X1000mm
1m
=14,500mm
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Dave traveled at .27 miles/min. What is his
speed in miles/hr?
.27 mile X 60 min = 16.0 mile/hr
min
1 hr
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Velocity – speed in a given direction
Why is it important to know an object’s speed
and direction?
Come up with examples of moving objects
where is it crucial to know their speed and
direction.
Ex. A hurricane is traveling 20km/hr
northward
◦ What is this object’s speed?
◦ What is the direction of this object’s motion
You can show the motion of an object on a
line graph by plotting distance vs time
Distance vs Time
5
Distance
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4
3
2
1
0
1
2
Time
3
4
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Steepness of a line is slope
Tells how fast one variable
changes in relationship to another
– rate of change (speed!!!)
The steeper the slope the faster
the speed
A constant slope= motion at a
constant speed
15
Distance

10
5
0
1
2
3
Time
4
5
Distance
Vertical difference between 2 point = Rise
Horizontal difference between 2 points = Run
Slope = Rise
Run
Ex. Rise = 400 m and Run= 2minutes
Slope= 400m/2 minutes = 200m/min
600
400
200
0
0
2
Time
7
6
Distance
5
4
3
2
1
0
1
2
3
4
5
6
7
Time
8
9
10