A-LevelPhysicsForces, density and pressureOct/Nov 2022Paper 1 Q131 Mark
A box of length 12cm and weight 0.43 N is placed on a horizontal table, with the greater part of its length overhanging the edge of the table. The edge of the table acts as a pivot. The centre of gravity of the box is at its geometric centre. To balance the box, a uniform sphere of diameter 2.4 cm is placed inside the box, touching one end, as shown. [Figure showing a box on a table with a sphere inside] Assume that the forces acting on the box are in the plane of the diagram. What is the minimum mass of the sphere that is needed to maintain the system in equilibrium?
A0.066 kg
B0.13 kg
C0.22 kg
D1.3 kg
✓ Correct Answer
The correct answer is B: 0.13 kg
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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