Who this is for: Cambridge IGCSE Coordinated Science (0654) students who want motion — speed, acceleration and graph interpretation — to become a reliable source of marks instead of a formula sheet without meaning.
What query it owns: how to understand and revise motion in Cambridge IGCSE Coordinated Science.
Why this is safe: this page owns the motion revision-guide angle, while Tutopiya’s Motion subtopic page owns the learning resource and the free Motion quiz owns the practice.

Motion describes how objects move through space over time. Cambridge IGCSE Coordinated Science (0654) expects you to calculate speed, distinguish speed from velocity, define acceleration, and interpret distance–time and speed–time graphs. This guide links each concept to the calculation and graph skills examiners reward.

Key takeaways

• Speed = distance ÷ time; unit m/s (or km/h).
• Velocity is speed in a stated direction; it is a vector quantity.
• Acceleration = change in velocity ÷ time; unit m/s².
• On a distance–time graph, gradient = speed; horizontal line = stationary.
• On a speed–time graph, gradient = acceleration; area under graph = distance travelled.

What is motion in Cambridge IGCSE Coordinated Science?

When an object moves, we describe how fast (speed), in which direction (velocity), and whether it is speeding up or slowing down (acceleration). Uniform motion means constant speed; accelerated motion means speed changes. Graphs provide a visual summary — reading gradients and areas is a core exam skill.

You can read the full explanation, graphs and notes on Tutopiya’s Motion subtopic page before you attempt questions.

Core equations and definitions

Quantity	Equation / definition	Unit
Speed	distance ÷ time (v = s ÷ t)	m/s
Average speed	total distance ÷ total time	m/s
Acceleration	(final velocity − initial velocity) ÷ time (a = (v − u) ÷ t)	m/s²
Uniform acceleration	v = u + at	m/s

Distance–time vs speed–time graphs

Graph type	Gradient gives	Area under graph gives
Distance–time	Speed	—
Speed–time	Acceleration	Distance travelled

A flat (horizontal) section on a distance–time graph means the object is not moving. A straight line sloping upward on a speed–time graph means constant acceleration.

Motion in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical motion stem
Calculate	Use equation with values	”Calculate the speed of the car.”
Define	Give precise meaning	”Define acceleration.”
Describe the motion	Interpret a graph section	”Describe the motion between 2 s and 5 s.”
Determine from graph	Read gradient or area	”Determine the acceleration from the graph.”

Worked exam-style stems (how to answer the wording)

1. “A car travels 300 m in 20 s. Calculate its speed.” Speed = distance ÷ time = 300 ÷ 20 = 15 m/s. Mark-scheme reward: correct substitution and unit.
2. “Define acceleration.” Rate of change of velocity (or change in velocity per unit time). Reward: change in velocity + per unit time.
3. “State what the gradient of a distance–time graph represents.” Speed. Reward: speed (not velocity unless direction stated).

Test yourself with the Motion quiz once you can calculate speed and read both graph types.

How motion connects to the rest of Coordinated Science physics

Motion builds on Length And Time and leads into Forces — unbalanced forces cause acceleration. It also links to Work and Energy. The Cambridge IGCSE Coordinated Science resource hub links every Motion subtopic.

Common mistakes students make

• Using distance and displacement interchangeably without checking the question.
• Forgetting that acceleration can be negative (deceleration).
• Reading the distance–time gradient as acceleration (it is speed).
• Not converting km/h to m/s before substituting into equations.
• Confusing speed (scalar) with velocity (vector with direction).

When you need more support

If motion questions keep costing marks, work through the Motion quiz, then get focused help from a Cambridge IGCSE Coordinated Science tutor.

Frequently asked questions

Is motion hard in Coordinated Science? The equations are simple — the challenge is graph interpretation and unit conversion, both of which improve with practice.

What is the difference between speed and velocity? Speed is how fast; velocity is speed in a given direction.

What does the area under a speed–time graph represent? The distance travelled.

How do I revise motion effectively? Practise speed calculations, interpret both graph types, then take the Motion quiz.

Ready to master Cambridge IGCSE Coordinated Science motion?

Start with the Motion subtopic page, then book a free trial with a Cambridge IGCSE Coordinated Science specialist to turn motion skills into guaranteed marks.

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