Graphs of Motion

Uniform velocity

Motion at a constant speed in a fixed direction, shown as a straight line on a distance–time graph.

EnglishUniform velocity
Bahasa MelayuHalaju seragam
中文匀速

How it is used

A car travelling at a steady 8 m/s in a straight line has uniform velocity. On a distance–time graph this is a straight sloping line, and in 10 s it covers 8 × 10 = 80 m.

Where it shows up in SPM

In Graphs of Motion (Form 5). It shows as a straight line on a distance–time graph, or a flat horizontal line on a speed–time graph.

Paper 2 questions ask you to identify the stage of uniform velocity and confirm the acceleration there is zero.

Don't confuse it with

AccelerationUniform velocity means the speed does not change, so the acceleration is zero; any non-zero acceleration means the velocity is not uniform.
Average speedUniform velocity is the actual speed at every instant of that stage; average speed is a summary over a whole journey that need not be uniform.

Open the chapter: Graphs of Motion →

Frequently asked questions

How do I spot uniform velocity on a graph?

On a distance–time graph, look for a straight sloping line, a constant gradient means a constant speed. On a speed–time graph, look for a flat horizontal line, showing the speed stays fixed while time passes.

Is uniform velocity the same as uniform speed?

In SPM motion-graph work they are treated the same: a constant speed along a straight path. Strictly, velocity also fixes the direction, but the graphs you meet here move in one straight line, so a steady gradient captures both.

Related terms

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