1. Making and Interpreting Distance – Time Graphs
Graphing Speed
Making and Interpreting
Distance – Time Graphs

2. GRAPHING SPEED DISTANCE-TIME GRAPHS Distance is plotted on
the vertical axis. D I S T A N C E
Time is plotted on the
horizontal axis.
TIME

3. CONSTANT SPEED If something is “constant” what does that mean?
It does not change
So…
what does the term constant speed mean?
Speed that does not change is constant speed.

4. GRAPHING CONSTANT SPEED
DISTANCE-TIME GRAPHS
straight
diagonal
line
t d
100 90 80 70 60 50 40 30 20 10 1 2 3 4 5 20 40 60 80
100 D I S T A N C E
(m)
TIME (sec)
Describe the shape of the line for constant speed

5. GRAPHING CONSTANT SPEED
DISTANCE-TIME GRAPHS
A has the >
slope therefore
it has the >
constant speed.
How do you know? A B C
t d
100 90 80 70 60 50 40 30 20 10 1 2 3 4 5 20 40 60 80
100 D I S T A N C E
(m)
TIME (sec)
Which object has the greatest constant speed?

6. GRAPHING AVERAGE SPEED
DISTANCE-TIME GRAPHS
A flat
horizontal
line means
motion
stopped.
What does this
part of the line
mean?
100 90 80 70 60 50 40 30 20 10
t d 1 2 3 4 5 10 30 40 80 D I S T A N C E
(m)
zigzag
TIME (sec)
Describe the shape of the line for average speed?

7. Average Speed Average speed is speed that changes or fluctuates.
Most moving objects travel at average speed,
they start from a stand still, begin slowly,
increase their speed, slow down, speed up,
and eventually slow to a stop.
On a distance-time graph average speed would
appear as a line that changes direction as it
goes across the graph. It would be described as
a zig-zag line.
A slanted line indicates that motion is occurring.
A flat horizontal line indicates that motion has
stopped but time continues.

8. Review
You will recall from a previous lesson that
Speed is calculated using the formula
s = d / t
What is the average speed of a 18 wheeler
driver who drives non-stop 1600 miles from
Houston to Los Angeles in 23 hours?
S = d / t
S = mi / 23 hrs.
S = m/hr.

9. Acceleration In order to understand acceleration you must
understand the difference in speed and velocity.
Speed is how long it takes a moving object to
travel a distance.
Velocity is speed in a given direction.
NOW, ACCELERATION IS THE RATE OF CHANGE
IN VELOCITY.
You must understand that if either speed or
direction changes, the object has undergone
acceleration.

10. I count 6 …. Let’s look at why this might be.
In this diagram, how many times will
the people experience acceleration
from where they are now to the end
of the ride?
Changes direction? 5 1
Speeds up 2
???
Speeds up 4
Is there any
other place
that its
velocity will
change? 3
Slowing down
is also considered
to be acceleration. 6
I count 6 …. Let’s look at why this might be.

11. Formula for CALCULATING ACCELERATION
final velocity - original velocity
time for change to occur
acc =
Vf - Vo
acc = t
At the top of the hill the roller coaster is moving 20 m/sec
and increases in speed to 40 m/sec at the bottom of the
hill. It takes 4 seconds to reach the bottom of the hill.
What is the roller’s coaster’s acceleration?
Vf_-_Vo
acc = t
40 m/s__-__20 m/s
acc =
4 sec
acc = 5 m/s/s

12. As it goes up the hill, it slows to 20 m/sec.
The total time from the bottom of the hill to
the top of the next hill is 5 seconds. What is
the acceleration of the roller coaster?
Vf__- Vo t
acc =
20 m/s_-_40 m/s
5 seconds
acc =
Notice that the answer
is a negative number.
This indicates that the
roller coaster slows down.
acc = - 4 m/s/s
Negative acceleration is also known as
__________________.
deceleration

13. CURVED GRAPHING ACCELERTION DISTANCE-TIME GRAPHS
100 90 80 70 60 50 40 30 20 10
t d 1 2 3 4 5 10 20 40 70
110 D I S T A N C E
(m)
CURVED
TIME (sec)
Describe the shape of a line showing acceleration.

14. Let’s check out the First Annual SHMS Snail Race results to see if you can interpret a distance time graph.
Graphing is something that you must learn how to do in order to be able to pass TAKS !

15. FIRST ANNUAL D C B A
SHMS Snail Races

16. INTERPRETING a c b d DISTANCE-TIME GRAPHS TIME (hr) SNAIL RACES
SHMS
SNAIL RACES
Results a c
100 90 80 70 60 50 40 30 20 10 b D I S T A N C E
(in) d
Pass out question
sheet for this slide.
TIME (hr)

17. Model Car
Races
Time
Total distance covered (meters)
(sec) A B C D 1 3 2 4
.25 6 8 .5 9 12 16 5 15 10 18 7 21 14 24 19 27 22 28 30 20 25 36
Construct a
distance –
time graph
for the values
in the data
table.
PASS OUT GRAPH
PAPER FOR THIS
EXERCISE.
NEATNESS
COUNTS !

18. Model Car Race Results GraphedI S T A N C E
(m)
TIME (sec)
Your graph should look similar to this.

19. We hope that you have been able to learn something from us.
The
End
We hope that you have been able to learn something from us.