1. G Dear ©2010 – Not to be sold/Free to use
Stage 4
Year 9
Graphs of
Physical
Phenomena
Time and Distance
Graphs
Press Ctrl-A
G Dear ©2010 – Not to be sold/Free to use

2. Time-Distance Graphs Cars do not change speed instantly.
Cars change speed gradually.

3. Average speed over a distance.
Time-Distance Graphs
Average speed over a distance.
Time
Distance B D A T
Distance
Average Speed =
Time D
S = T 3

4. Average speed over a distance.
Time-Distance Graphs
Average speed over a distance. A |
1hr
2hr
3hr
4hr
5hr
6hr
7hr
8hr
9hr
10km-
20km-
30km-
40km-
50km-
55-45=
-10km
2hr B
7-5=
-10
S = 2
= -5 km/h 4

5. Instantaneous speed at a point.
Time-Distance Graphs
Instantaneous speed at a point.
Time
Distance D T
Distance
Instantaneous Speed =
Time D
S = T 5

6. Instantaneous speed at a point.
Time-Distance Graphs
Instantaneous speed at a point. |
1hr
2hr
3hr
4hr
5hr
6hr
7hr
8hr
9hr
10km-
20km-
30km-
40km-
50km-
25-55 =
-30km
8-6=
2hr
-30
S = 2
= -15 km/h 6