2. Describing a journey made by
an object is very boring if you
just use words. As with much
of science, graphs are more
revealing.
Plotting distance against time
can tell you a lot about a
journey.
4. Time always runs
horizontally (the
x-axis). The arrow
shows the
direction of time.
The further to the
right, the longer
time from the
start.
5. Distance runs
vertically (the
y-axis). The
higher up the
graph we go,
the further we
are from the
start.
6. If something is not
moving, a horizontal line is
drawn on a distance-time
graph.
Time is increasing to the
right, but its distance does
not change.
This graph shows an
object that is stationary.
7. If something is moving
at a steady speed, it
means we expect the
same increase in
distance in a given
time.
Time is increasing to
the right, and distance
is increasing steadily
with time.
9. Both the lines below
show that each object
moved the same
distance, but the
steeper yellow line got
there before the other
one.
What does this
indicate?
10. A steeper slope
indicates a larger
distance moved in
a given time. In
other words,
higher speed.
This is shown in
yellowyellow.
11. YellowYellow: speed =
distance / time =
30 m / 10 s = 33
m/sm/s
BlueBlue: speed =
distance / time =
20 m / 20 s = 11
m/sm/s
12. For the first
part of the
journey shown
by the graph
below, the
object moved
at a steady
(slow) speed.
13. Then the object
suddenly increased its
speed, covering a much
larger distance in the
same time.
The speed increased in
the second part of the
journey.
14. The line below is
curving upwards.
This shows an
increase in speed,
since the slope is
getting steeper
over time.
15. In other
words, in a
given time, the
distance the
object moves
is larger.
It is
accelerating.
16. There are three parts
to the journey shown
here… Where is the
graph showing motion
that is:
Stopped?
Moving at a quick
constant speed?
Traveling at a slow
constant speed?
A
B
C
17. The graph below shows several stages of motion:
Stage 1: 100 m in 10 s.
Stage 2:Stage 2: 50 m in 10 s.
Stage 3: 150 m in 20 s.
Calculate the speeds of
each stage, indicated by
the colors.
18. The graph below shows several stages of
motion: Stage 1: speed = distance /
time = 100 m / 10 s = 10
m/s
Stage 2:Stage 2: speed = distance /
time = 50 m / 10 s = 5 m/s5 m/s
Stage 3: speed = distance /
time = 150 m / 20 s = 7.5
m/s.
19. The graph below shows several stages of
motion:
Stage 1: constant speed at
a relatively high rate
Stage 2:Stage 2: constant speed at
a relatively slow rate
Stage 3: constant speed at
a “medium” rate (between
the others)
20. The graph below shows several stages of
motion:
The slope of the line
(its steepness)
indicates rate of
change of position.
Speed can be
estimated by the
slope of the line…
faster, slower, etc.
21. Distance vs. time graphs also indicate the
position of the object.
Stage 1 & Stage 2:Stage 2: object is
moving away from the
starting point
Stage 3: object is moving
back toward the starting
point (it comes back to zero)
22. The steeper the line on a distance vs.
time graph, the faster the object’s
speed.
A curved line indicates a change in
speed (accelerating or decelerating).
23. Lines pointing up indicate moving
away from the starting location.
Lines pointing down indicate moving
back towards the starting location.
24. Let’s see how much this makes
sense to you…
This is not for a grade, just to let me
know how much of this and what
parts of it you “get.”
25. To learn about speed vs. time
graphs, visit this link:
http://www.gcse.com/fm/stg.htm