Distance-time and velocity-time graphs

In a nutshell

Both distance-time graphs and velocity-time graphs can be useful in finding out more about the motion of an object. In a distance-time graph, the distance travelled is plotted on the $y$ -axis and time is plotted on the $x$ -axis. Similarly, a velocity-time graph has velocity plotted on the $y$ -axis and time plotted on the $x$ -axis.

Distance/time graphs

In a distance-time graph, the gradient of the graph is the speed of the object. The features on the distance-time graph gives information about how the motion of the object is changing.

Physics; Motion and forces; KS4 Year 10; Distance-time and velocity-time graphs

A.	Distance
B.	Time

Feature	Description
1.	A straight line section means that the object is moving with a constant speed. Positive gradient indicates the object is moving away from the origin, while a negative gradient means it is travelling towards it. A steeper gradient means the object is moving faster.
2.	A flat section means the object has stopped moving.
3.	A curved section means that the object is changing speed. A steeping curve means the object is accelerating.
4.	A curve that is levelling off means the object is decelerating.

Velocity/time graphs

In a velocity-time graph, the gradient of the graph is the acceleration of the object. Acceleration is how quickly an object is speeding up, these graphs may be a bit more tricky to interpret.

Physics; Motion and forces; KS4 Year 10; Distance-time and velocity-time graphs

A.	Velocity
B.	Time

Feature	Description
1.	A straight line section with a positive gradient means that the object is constantly getting faster. It is undergoing constant acceleration.
2.	A curved section means that the object is changing acceleration.
3.	A flat section means that the object is moving at a constant velocity. In other words, the object is not changing speed or changing direction.
4.	A straight line section with a negative gradient means that the object is slowing down at a constant rate. The object is said to be decelerating or experiencing constant deceleration.

A very useful property of velocity-time graphs is that the area under the graph is the distance travelled by the object. To find the distance travelled over a specific time interval, the area under the graph can be calculated during that particular time interval.