A-LevelPhysicsForces, density and pressureOct/Nov 2017Paper 1 Q121 Mark
The diagram shows a solid cube with weight W and sides of length L. It is supported at rest by a frictionless spindle that passes through the centres of two opposite vertical faces. One of these faces is shaded. [Figure showing a cube with spindle through its centre] The spindle is now removed and replaced at a distance L/4 to the right of its original position. [Figure showing the cube with the spindle moved L/4 to the right] When viewing the shaded face, what is the torque of the couple that will now be needed to keep the cube at rest?
AW L / 4 anticlockwise
BW L / 4 clockwise
CW L / 2 anticlockwise
DW L / 2 clockwise
✓ Correct Answer
The correct answer is B: W L / 4 clockwise
📋 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.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep