Because motion is most commonly described with respect to time, graphs with time on the x-axis and either distance, displacement or velocity on the y-axis are useful in describing motion. Such graphs are rich with information about the motion of an object and you should become familiar with their interpretation as well as how to draw them.

1. Preliminary Physics
8.4 Moving About
Graphing Motion

2. Distance-Time Graphs
• The gradient of the
graph is speed
• A straight line means
constant speed
• A curve means that the
speed is changing and
the object is accelerating

3. Describe the motion of this
object.
What could it be?

4. Displacement-Time Graphs
• The gradient of the
graph is velocity,
• A straight line means
constant velocity,
• A curve means that the
velocity is changing and
the object is
accelerating,
• A positive gradient
(sloping to the right)
means positive velocity,
and
• A negative gradient
(sloping to the left)
means negative velocity.

5. Describe the motion of this
object.
What could it be?

6. Velocity-Time Graphs
• The gradient of the
graph is acceleration
• A straight line means
constant acceleration
• A positive gradient
means positive
acceleration
• A negative gradient
means negative
acceleration
• The area under the
graph is the
displacement
• An area above the x-axis
is positive displacement
• An area under the x-axis
is negative displacement

7. Describe the motion of this
object.
What could it be?

8. Describe the motion of this
object.
What could it be?

9. These graphs show how
distance, velocity and
acceleration all vary with
time for the same moving
object.

10. Example 1
a) Which runner won the
race?
b) Which runner stopped
for a rest?
c) How long was the
stop?
d) How long did Bob take
to complete the race?
e) Calculate Albert’s
average speed.

11. Example 2
a) During which section
did the bus have the
greatest positive
acceleration and what
was it?
b) During which section
did the bus have the
greatest negative
acceleration and what
was it?
c) How far did the bus
travel in 25 s?
Velocity(ms-1)

12. Example 3
For a ball dropped from a
height of 1.0 m, draw
a) a displacement- time
graph
b) a velocity-time graph
c) an acceleration-time
graph.