Who this is for: Cambridge IGCSE Physics (0625) students who want motion — speed, velocity, acceleration and motion graphs — to become a reliable source of marks instead of formulas they apply without understanding what the graph shows.
What query it owns: how to understand and revise motion in Cambridge IGCSE Physics.
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 is the foundation of the Motion, Forces and Energy unit in Cambridge IGCSE Physics (0625). Examiners test speed, velocity, acceleration, distance–time graphs and velocity–time graphs in almost every paper cycle. Students who memorise equations without linking them to what the graph describes lose method marks quickly. This guide explains the core relationships, how to read each graph type, and where to practise each skill.

Key takeaways

• Speed = distance ÷ time (scalar); velocity = displacement ÷ time (vector, includes direction).
• Acceleration = change in velocity ÷ time; units m/s².
• Distance–time graph: gradient = speed; horizontal line = stationary.
• Velocity–time graph: gradient = acceleration; area under graph = distance travelled.
• Uniform acceleration: use v = u + at, s = ut + ½at², v² = u² + 2as — only after identifying u, v, a, s, t from the question.

What is motion in Cambridge IGCSE Physics?

Motion describes how objects move and how their position changes over time. Cambridge IGCSE Physics (0625) covers average and constant speed, acceleration, interpreting and sketching motion graphs, and solving problems with the equations of motion for uniform acceleration. Questions range from straightforward calculations to graph interpretation and describing motion from a story or diagram.

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

The core ideas you must master

Idea	What it means	How the exam uses it
Average speed	Total distance ÷ total time	”Work out average speed for the journey.”
Acceleration	Rate of change of velocity	”Calculate the acceleration.”
d–t graph gradient	Speed at that point	”Find the speed at t = 3 s.”
v–t graph gradient	Acceleration	”State the acceleration from the graph.”
v–t graph area	Distance travelled	”Find the distance in the first 5 s.”

Distance–time vs velocity–time graphs

Feature	Distance–time	Velocity–time
Gradient means	Speed	Acceleration
Horizontal line	Stationary (not moving)	Constant velocity
Steeper line	Faster speed	Greater acceleration
Area under graph	Not used for distance	Distance travelled
Curved line	Changing speed	Changing acceleration

How to solve motion problems — step by step

1. List known quantities with units — convert to m, s, m/s before substituting.
2. Identify the graph type if a diagram is given — d–t or v–t?
3. Choose the method — gradient, area, or equations of motion for uniform acceleration.
4. Substitute into the correct equation; show rearrangement for method marks.
5. State the answer with unit and sensible direction if velocity or displacement.

Test yourself with the free Motion quiz once you have worked through graph and equation practice.

Graph reading vs equation use: which approach does the question want?

Situation	What to do	Typical signal words
Read speed from d–t graph	Find gradient at that point	”Use the graph to find the speed at 4 s.”
Distance from v–t graph	Find area under graph	”Find the distance travelled in the first 6 s.”
Uniform acceleration calculation	Use v = u + at or s = ut + ½at²	”The car accelerates from rest at 2 m/s².”
Describe motion from graph	Link shape to story	”Describe the motion between A and B.”
Average speed	Total distance ÷ total time	”Work out the average speed for the whole trip.”

Motion in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical motion stem
Calculate / Work out	Numerical answer with method	”Calculate the acceleration of the object.”
State	Short factual answer	”State what the gradient of a v–t graph represents.”
Describe	Motion in words from graph or scenario	”Describe the motion from t = 0 to t = 5 s.”
Sketch	Draw graph shape with labels	”Sketch a v–t graph for constant acceleration.”
Use the graph	Read gradient or area	”Use the graph to find the distance travelled.”

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

1. “A car travels 150 m in 10 s at constant speed. Calculate its speed.” Speed = 150 ÷ 10 = 15 m/s. Reward: correct division with unit.
2. “A object accelerates uniformly from 5 m/s to 25 m/s in 4 s. Calculate the acceleration.” a = (v − u) ÷ t = (25 − 5) ÷ 4 = 5 m/s². Reward: change in velocity ÷ time.
3. “On a velocity–time graph, the line from t = 0 to t = 4 s forms a triangle with the axes (maximum velocity 8 m/s). Find the distance travelled.” Area = ½ × base × height = ½ × 4 × 8 = 16 m. Reward: area under v–t graph identified.

When you can recognise the wording instantly, work the full set on the Motion quiz and link back to Physical Quantities and Measurement Techniques for unit checks.

How motion connects to the rest of the syllabus

Motion feeds directly into Mass and Weight and forces (F = ma). Graph skills reappear in electricity and thermal physics. Physical Quantities and Measurement Techniques provides the scalar/vector foundation. The Cambridge IGCSE Physics resource hub links every Motion, Forces and Energy subtopic.

Common mistakes students make

• Using distance–time gradient as acceleration (it gives speed).
• Using area under d–t graph for distance (area under v–t gives distance).
• Averaging two speeds for average speed instead of total distance ÷ total time.
• Forgetting direction when describing velocity or displacement.
• Substituting into v = u + at without checking uniform acceleration applies.

When you need more support

If motion graphs or acceleration calculations keep costing marks, work through the Motion quiz, then get focused help from a Cambridge IGCSE Physics tutor.

Frequently asked questions

Is motion hard in Cambridge IGCSE Physics? The equations are few — marks are lost from misreading graphs and confusing d–t with v–t.

What is the difference between speed and velocity? Speed is scalar (magnitude only); velocity is vector (magnitude and direction).

How do you find distance from a v–t graph? Find the area under the graph — triangle, rectangle or trapezium as appropriate.

How do I revise motion effectively? Practise one d–t and one v–t question daily, learn what gradient and area mean on each, then take the Motion quiz.

Ready to master Cambridge IGCSE Physics motion?

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

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