Gradients of Curves

You can estimate the gradient of a curve at a given point by drawing a tangent to the curve at that point
This distance-time graph shows a runner accelerating at the start of a race
Always draw a large triangle to make your estimate as accurate as possible
Pay attention to the scale when you calculate the gradient

To work the average rate of change between two points draw a straight line between these points on the graph and find its gradient
This is the same as working out
- Change in voltage / change in time
You need to find the point on the curve with the same gradient
That means you need to find a tangent to the curve that is parallel to the first line
Slide a transparent ruler across the graph until it just touches the curve
You can show how you got your answer by drawing the tangent to the curve at this point