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S3 Science: Forces, Motion, Speed-Time Graphs and Net Force (Paper 1: basics)
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S3 Science: Forces, Motion, Speed-Time Graphs and Net Force (Paper 1: basics)
This first paper builds three foundations: the speed formula, unit conversion and direction in net force.
Direct answers Check the units before writing the answer, since most errors happen at that step.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: S3 Science: Forces, Motion, Speed-Time Graphs and Net Force |
| Level | S3 Science |
02 Questions (10 items)
- FoundationA student runs 100 metres in 20 seconds. What is the average speed?
- FoundationA bus covers 60 kilometres in 1.5 hours. What is its average speed?
- FoundationWalking at 4 m/s for 12 seconds, how far do you travel?
- IntermediateHow long does it take to run 240 metres at 6 m/s?
- IntermediateHow many m/s is 36 km/h?
- IntermediateHow many km/h is 15 m/s?
- ChallengeOn a distance-time graph, what quantity grows when the line is steeper?
- ChallengeAn object feels 10 N to the right and 4 N to the left. What is the net force?
- ChallengeTwo 5 N forces act on one object in opposite directions. How does it move?
- Error redoA student works out that 120 metres in 30 seconds is 4 km/h. What is the correct answer?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | 5 m/s | Speed is distance over time, so 100 divided by 20 gives 5 in metres per second. |
| 2 | 40 km/h | Hours and kilometres already match, so dividing 60 by 1.5 gives 40. |
| 3 | 48 m | Distance is speed multiplied by time, so 4 times 12 is 48 metres. |
| 4 | 40 seconds | Time is distance over speed, so 240 divided by 6 gives 40 seconds. |
| 5 | 10 m/s | Converting from km/h to m/s means dividing by 3.6, so 36 gives 10. |
| 6 | 54 km/h | Converting from m/s to km/h means multiplying by 3.6, so 15 gives 54. |
| 7 | The speed | The slope of a distance-time graph is the speed, so a steeper line covers more distance in the same time. |
| 8 | 6 N to the right | Opposite forces subtract, so 10 minus 4 leaves 6 in the direction of the larger force. |
| 9 | It stays at rest or keeps a constant velocity | The net force is zero, so by Newton first law the state of motion does not change. |
| 10 | 4 m/s, which is 14.4 km/h | Metres over seconds gives metres per second only, and changing to km/h needs another factor of 3.6. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
Three basics: speed is distance over time with consistent units, net force is what remains after combining all forces, and the slope of a distance-time graph is the speed.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.