PH02-01 Physics Coming soon
Distance-time graphs
PH02-01
This lesson is coming soon.
In this lesson
Draw a distance-time graph from a table of measurements, read what each part of the line says about the motion, and find the speed of the object from the gradient.
What it covers
- The axes: time along the bottom, distance up the side, each labelled QUANTITY, SYMBOL, UNIT in the physics style - time, t, seconds; distance, s, metres
- Plotting a distance-time graph from a table of measurements, choosing a scale that uses most of the grid, and drawing a straight line or a smooth curve through the points
- What each shape of line says about the motion: a straight sloping line is a steady speed, a horizontal line is stopped, a steeper line is faster, a curve is a speed that is changing
- Why the line can only ever go up or stay flat on a DISTANCE-time graph - distance already travelled does not un-travel
- The gradient IS the speed - not 'shows' the speed, not 'is related to' the speed; the number you get from the gradient, with its unit, is metres per second
- Taking the gradient as a change in distance divided by the matching change in time, drawn as a triangle ON the line, with the corners on gridlines
- Why the triangle must be big: a small triangle magnifies a reading error
- Taking the gradient of a section that does NOT start at the origin, so change-in-distance-over-change-in-time is forced rather than optional
- Reading a value off the graph at a gridline rather than eyeballing between gridlines
Key words
For: AQA GCSE 8463, Edexcel GCSE 1PH0, OCR GCSE J249
On the specification
| Board | Spec | Statement |
|---|---|---|
| AQA GCSE 8463 | 4.5.6.1.4a | The distance–time relationship |
| Edexcel GCSE 1PH0 | 2.7 | Analyse distance/time graphs including determination of speed from the gradient |
| OCR GCSE J249 | P2.1e | Relate changes and differences in motion to appropriate distance-time, and velocity-time graphs; interpret lines and slopes |
For teachers
This GCSE Physics lesson teaches distance-time graphs. By the end, students should be able to draw a distance-time graph from a table of measurements, read what each part of the line says about the motion, and find the speed of the object from the gradient. It works through three worked examples and the mistakes examiners report, and suits Foundation and Higher tier students.