There are three very important things to remember about velocity time graphs.

1. The distance travelled is the area under the graph.

2. The gradient is equal to the acceleration. If the graph is sloping up – the gradient is positive – there is acceleration. If the gradient is negative – the graph is sloping down – there is deceleration - the acceleration is negative.

3. The average speed is equal to the total distance (the area under the graph) divided by the total time.

4. If the speed is constant the graph is horizontal (the gradient is zero).

The above graph shows the motion of a car. The car travels with constant velocityfor the first second.

The area under the graph is a trapezium. The distance travelled is equal to the area.

Between 1 and 5 seconds it decelerates :

There is deceleration of