Cambridge International AS & A Level · P3 · structured
Whole cycles and useful repetition
AS practical 4: time cycles and decide what repeats mean · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 8
- Topics
- 3
- Answer
- Complete
Constructed times for 15 complete oscillations are 22.1, 22.5 and 22.3 s. Determine T and its half-range uncertainty. Describe a reference/counting method and explain why timing 15 cycles helps. Name a useful non-timing repeat and a systematic error that averaging will not remove.
- (a)
Calculate mean, half-range, T and Delta T.
4 marks - (b)
Explain timing reference and advantage.
2 marks - (c)
Explain purposeful repetition and its limit.
2 marks
Ready to self-mark?Reveal the detailed answer guide
(a)
Calculate mean, half-range, T and Delta T.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
22.3 s, 0.2 s, 1.4867 s, 0.0133 s before rounding.
(b)
Explain timing reference and advantage.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
Same-direction crossing; time 15 whole cycles; reduced relative reaction uncertainty.
(c)
Explain purposeful repetition and its limit.
Identify what the question is testing, organise the response into distinct mark-earning points, and make every conclusion traceable to a physical principle or to the evidence supplied.
- 1
Reposition/rotate diameter measurements; averaging does not remove zero error.
Complete marking guidance
Use these worked steps alongside the part-by-part answers. They explain the method and mark allocation; they do not add extra marks.
- Mean=22.3 s and half-range=0.2 s: 2 marks.
- T=22.3/15=1.4867 s, Delta T=0.2/15=0.0133 s: 2 marks; accept consistent reporting such as 1.487 ± 0.013 s.
- Same mark and direction, with zero at start and 15 whole cycles: 1 mark.
- Reaction-time contribution per cycle is reduced by division by 15: 1 mark.
- One purposeful non-timing repeat and one persistent systematic error: 2 marks.
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