# 1.9.3 Video task: graphing the journey

Now watch the video ‘Single-track minders’. There are four activities associated with the video sequence. Try the appropriate activity when you are asked to stop the tape. You should tackle Activities 25 and 26 at the end of the video.

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Now watch the video**.

Video, Click to watch part one

#### Transcript: Single-track minders - Part 1

## Activity 23: Graphing the journey

On a sheet of graph paper, plot a distance-time graph for the journey from Bridgnorth to Kidderminster. (Note that the graph shown on the video is actually a position-time graph, because actual places rather than distances from a single place are shown on the vertical axis.) The map shown on the video is repeated in Figure 54. Note down briefly what information you will need to plot the graph.

Work out the highest and lowest speeds reached on the journey. In what sections of the line do they occur?

What is the average speed for the complete journey?

Make some notes to explain how you made these calculations.

### Discussion

The highest speed is reached on the section between Hampton Loade and Highley. This is where the slope of the distance-time graph is steepest. The 3.3 km section was covered in 7 minutes. So the average speed is 3.3/7=0.47 km per minute, or about 28 km per hour.

The graph indicates that the lowest speed occurs on the section between Bewdley and Kidderminster. Here, the slope of the graph is least. The train covers the 4.5 km in 20 minutes, an average speed of 4.5/20=0.225 km per minute, or 13.5 km per hour.

The complete journey of 24.5 km is covered in 70 minutes. So the average speed is 24.5/70=0.35 km per minute, or 21 km per hour.