Theory
Calculating the slope of a physics graph
The slope of a graph tells you how much the vertical quantity changes per horizontal step.
Read off two points that clearly lie on the line.
Use: slope = change in y : change in x.
- Read two pointsTake two clear points from the graph.
- Calculate the vertical changeWork out the intermediate step using the values from the problem.
- Calculate the horizontal changeWork out the intermediate step using the values from the problem.
- Divide the vertical change by the horizontal changeWork out the intermediate step using the values from the problem.
A straight graph passes through (2, 5) and (6, 17). Calculate the slope.
- Read two pointsPoint 1 = (2, 5). Point 2 = (6, 17).
- Calculate the vertical change17 - 5 = 12.
- Calculate the horizontal change6 - 2 = 4.
- Divide the vertical change by the horizontal change12 ÷ 4 = 3.