Cambridge International AS & A Level · P3 · structured
From limitation to justified modification
AS practical 9: repair the actual experiment · Original GioPhysics question with a detailed, mark-by-mark answer guide.
- Demand
- demanding
- Marks
- 7
- Topics
- 4
- Answer
- Complete
A spring's broad bottom coil is 4 cm in front of a fixed ruler; the instructions already say to wait for settling and view the scale at eye level. Constructed results are F=(2.00 ± 0.02) N and x=(0.025 ± 0.002) m. Identify and quantify the dominant uncertainty. Draw and describe one new feasible improvement, explain its effect, and reject one suggestion that merely repeats existing instructions.
- (a)
Identify and compare uncertainty contributions.
3 marks - (b)
Describe a new feasible repair clearly in words or a labelled sketch.
3 marks - (c)
Reject an already-provided instruction as an improvement.
1 mark
Ready to self-mark?Reveal the detailed answer guide
(a)
Identify and compare uncertainty contributions.
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
Extension endpoint ambiguity; 8% extension versus 1% force.
(b)
Describe a new feasible repair clearly in words or a labelled sketch.
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
Thin pointer and close fixed ruler, common read edge, constant/accounted pointer mass.
(c)
Reject an already-provided instruction as an improvement.
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
Settling or eye-level viewing alone adds nothing new here.
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.
- Specific extension ambiguity caused by broad displaced endpoint: one mark.
- 8% versus 1%, correctly compared: two marks.
- Labelled sketch or clear equivalent showing pointer and nearby ruler: one mark.
- Operating detail and causal benefit, with pointer mass noted: two marks.
- Identify already-provided settling/eye-level instruction as not a new modification: one mark.
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