FRQ — System of Particles and Rotational Motion

Long answer·Hard exam skill (4/5)·No calculator

Difficulty guide

The label describes the problem, not your ability.

1/5 - Foundational

Warm-up setup; checks one basic idea.

2/5 - Routine exam skill

Normal syllabus skill; usually one main rule or interpretation.

3/5 - Standard multi-step

Exam-style problem with multiple steps or a common trap.

4/5 - Hard exam skill

High-end exam problem; combines methods carefully.

5/5 - Challenge

Stretch problem beyond normal exam pressure.

Question

A body initially at rest explodes into two fragments. A

1\text{ kg}

fragment moves east at

6\text{ m s}^{-1}

and a

2\text{ kg}

fragment moves west at

3\text{ m s}^{-1}

. External force during the explosion may be neglected.

Total: 3 marks

(a) Find the total momentum after the explosion. (1 mark)

(b) Find the centre-of-mass velocity after the explosion. (1 mark)

Your response (optional — you can also work on paper)

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