A-LevelPhysicsDynamicsOct/Nov 2020Paper 1 Q111 Mark
The diagram shows a 'ballistic pendulum'. [Figure 11.1] A pellet of mass m travelling at a speed u hits a stationary block of mass M. The pellet becomes embedded in the block and causes the block to move at a speed v immediately after the impact. When a pellet of mass 2m, travelling at a speed 2u, hits a block of mass 2M, what is the speed of the block immediately after the impact? (Neglect the small increase in the mass of the block as the pellet's mass is added during the collision.)
Av
Bv√2
C2v
D4v
✓ Correct Answer
The correct answer is C: 2v
📋 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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