Calculate speed and specify velocity direction
Connect distance per time to speed and include direction when describing velocity.
Section 1.2 · Motion
Exam scope and assessment notes
Core and Extended · Physics 0972, 2026–2028, section 1.2. Core includes speed, velocity direction, distance–time and speed–time interpretation, straight distance–time gradients, speed–time areas and near-Earth free-fall acceleration. Numerical acceleration and the resistance/terminal-velocity explanation are Supplement requirements, taught in separately labelled Extended lessons. Written practice is self-checked; cumulative assessment, supervised practical experience and human subject-teacher review remain pending. Cambridge states that IGCSE 0972 has the same subject content as IGCSE 0625, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Convert metres, kilometres, seconds and minutes.
- Rearrange a simple equation.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Four minutes is how many seconds?
What you will learn
- Use speed = distance/time with consistent units.
- Distinguish a speed from a directed velocity.
Calculate a rate
Speed is distance travelled per unit time. For a constant-speed journey of 120 m in 15 s, speed is 120/15 = 8 m/s. The unit describes the rate: eight metres are travelled in each second of this motion. Rearranging v = s/t gives s = vt and t = s/v.
Before substituting, make the distance and time units match the requested rate. A distance of 1.2 km is 1200 m and four minutes are 240 s, so the rate is 5 m/s. A speed written in km/h is divided by 3.6 to express the same rate in m/s.
Velocity includes a direction
Velocity is speed in a given direction. Speed 8 m/s can accompany velocity 8 m/s east or 8 m/s west. Those velocities differ despite identical speed magnitudes. A change of direction changes velocity, even if an object's speed remains constant.
When motion includes turns or stops, a single distance/time result is an average speed. Do not assume it was the speed at every instant. The distance travelled is the whole path; a return to the starting point does not erase that distance or imply that the average speed was zero.
Pause and explain
Which statement specifies a velocity?
Worked example
A cyclist covers 1.2 km east at constant speed in four minutes. Find the speed and velocity.
Show the worked solution
- Convert distance to 1200 m and time to 240 s.
- Speed = 1200/240 = 5 m/s.
- Velocity is 5 m/s east.
Answer Speed 5 m/s; velocity 5 m/s east.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A cyclist covers 1200 m east in 240 s at constant speed. Find speed and velocity.
Give me a hint
Calculate the magnitude first, then add the direction.
Compare my reasoning
- Use v = s/t.
- 1200/240 = 5 m/s.
- Velocity is 5 m/s east.
5 m/s; 5 m/s east.
Look for these in your work
- Divide distance by time.
- Supply velocity direction.
A vehicle moves 72 km/h west. Find its velocity in m/s and distance travelled in 15 s at that constant rate.
Give me a hint
Convert km/h before using seconds.
Compare my reasoning
- 72/3.6 = 20 m/s.
- Velocity is 20 m/s west.
- Distance = 20 × 15 = 300 m.
20 m/s west; 300 m.
Look for these in your work
- Convert the rate.
- Use distance = speed × time.
Two cars move at 12 m/s, one north and one east. Are their speeds and velocities equal?
Give me a hint
Direction changes a velocity but not its speed magnitude.
Compare my reasoning
- Both magnitudes are 12 m/s.
- Their directions differ.
- Speeds are equal; velocities are different.
Equal speeds, different velocities.
Look for these in your work
- Compare magnitudes.
- Compare directions separately.
Common mistakes
- Include direction when a velocity is requested.
- Minutes are not seconds.
- An average rate does not prove constant motion.
What can you explain now?
A train moves 72 km/h east. Express its velocity in m/s.
Compare with the explanation
20 m/s east.
72/3.6 = 20; retain the direction.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Convert a speed into m/s, then write two different velocities with that same magnitude.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.