Chapter 1, Section 1
Speed and Motion
Recognizing Motion
1. What’s happening to the distance
between the bus and the light
posts as the bus is moving?
2. Which of the two objects is a
reference point? So what is a
reference point?
3. What reference points do you see
when you walk to school or class?
Calculating Speed
• What is the average speed
limit on the freeway?
• What are the two parts of a
speed measurement?
dis tan ce
»Speed =
time
Calculating Speed
Speed =
dis tan ce
time
time = 0 s
t = 15 s
distance = 0 m
d = 30 m
What is the dog’s speed?
30m/15s = 2m/s
Making a Speed Graph
X (Time in sec) Y (Distance in
meters)
0
0
1
5
2
20
3
45
4
80
5
125
Speed
140
Distance (m)
120
100
80
John
60
40
20
0
0
1
2
3
Time(s)
4
5
Slope = RISE/RUN
ONLY for straight parts of a graph!
140
Distance (m)
120
100
80
John
60
RISE
40
20
RUN
0
0
1
2
3
Time(s)
4
5
Constant Speed
1. If a ship traveling in the
ocean keeps the same speed
for several hours, it is going
at a _________ speed.
2. A horse ran 21 meters in 3
seconds, what was it’s speed?
• 21 m ÷ 3 s = 7m/s
Average Speed
• When a bicyclist is racing up
and down mountains, his
speed _______.
• You can use the ________
speed to describe the motion
of that bicyclist at every
point during the race.
Average Speed
• Average Speed =
total distance ÷ total time
• If a cyclist travels 32 km in
the first 2 hours and 13 km
in the last 1 hour, what was
his average speed?
– 32km + 13km = 45km
– 2h + 1h = 3h
– 45km ÷ 3h = 15km/h
Velocity
• Velocity always includes
speed and ___________.
• Which is an example of
velocity?
• Wind at 30mi/hr heading east
• Car traveling 65mi/hr
Exploring Motion Graphs
1. Is this
graph
showing a
constant
speed?
2.What is the
total time &
distance?
Exploring Motion Graphs
1. What
happened
during the
6th to 8th
minutes?
2.What effect did that have
on the average speed?
Exploring Motion Graphs
1. What is the
difference
between the
jogger’s
speed on the
third day and
the first
day?
2.What is the total distance & time?
Solving Speed Problems
• Use the Speed Triangle
s
d
t
• Figure out if you must find speed, time
or distance from the problem.
• Cover up the letter you are trying to
find to see what you must do.
Speed, Time, Distance Practice
Problems
1. Which has a greater speed, a hawk that
travels 600m in 60s, or an eagle flying
60m in 5s?
2. How long would it take to travel 30
meters if you were running at a speed of
2 meters/second?
3. If your average speed in a car was 45
miles/hour, how far would you get if you
drove for 4 hours?
Draw 3 Motion Graphs
1. Label the x and y-axis with time
and distance.
2. The first graph should represent
slow motion.
3. The second graph should
represent a faster motion.
4. The third graph should represent
an even faster motion.
Balloon Demonstration
1. Blow up the balloon and hold firmly
shut.
2. Describe the motion of the balloon
right now.
3. What could you do to make the
balloon move?
4. Release the balloon and describe
when the balloon changes its speed
or direction.