Acceleration from Velocity-Time Graphs
Reading a velocity-time graph two ways: the gradient gives the acceleration, and the area under the line gives the distance travelled. A negative gradient shows slowing down.
What a learner can do afterwards
- Calculates acceleration as a gradient and quotes it in metres per second squared
- Finds distance travelled from the area under a velocity-time graph made of straight sections
- Sketches the distance-time graph and the velocity-time graph of the same journey and says how they differ
1 · Read
Acceleration tells you how fast velocity changes. A car going from rest to 20 metres per second in 5 seconds has acceleration 4 metres per second squared. Slowing down counts too, pointing the opposite way to the motion.
On a velocity-time graph, acceleration is the steepness of the line. A steep upward slope means big acceleration, a flat line means steady speed with zero acceleration, and a downward slope means the object is slowing down.
The area under the line equals the distance travelled. If the graph is made of straight sections, split the area into rectangles and triangles, work out each chunk, then add them up. Try it: 10 metres per second for 6 seconds is a rectangle of 60 metres.
Motion graphs come in pairs telling one story two ways. For steady speeding up, the distance-time graph curves upward while the velocity-time graph is a straight rising slope. Always finish by asking if your answer makes sense on the graph.
Read acceleration from the slope and distance from the area.
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.