• What kind of motion happens when an object rolls down a hill?

Distance, Speed and Time Graphs

The distance (position) vs. time graph

• Motion graphs are an important tool used to show the relationships between distance, speed, and time.

A runner can learn more about performance by studying data and graphs.

The distance vs. time graph

• Distance vs. time data tells you the runner’s distance at different points in time.

• The runner is at 50 meters after 10 sec., 100 meters after 20 sec. and 150 meters at 30 sec.

Graphs show relationships

• A good way to show a relationship between two variables is to use a graph.

• A graph makes it easy to see if changes in one variable cause changes in the other variable (the effect).

3.2 The distance vs. time graph

• To graph data, you put distance on the vertical (y) axis .

• Time goes on the horizontal (x) axis.

• Data are plotted between x and y axis.

Reading a graph

• A graph can give you an accurate answer even without doing the experiment.

• Students doing an experiment measured the speed of the car at 20, 40, 60, and 80 cm positions.

• They want to know the speed at 50 cm.

Slope

• You can use distance vs. time graphs to quickly compare the speeds of different objects.

A steeper line on a distance vs. time graph means a faster speed.

Distance vs. time graphs

• The distance vs. time graph has distance on the y-axis and time on the x-axis.

Which runner has the fastest constant speed?

Speed vs. time graphs

These graphs each show the same event.What differences do you notice?

Do these graphs display the same data?