FRQ — System of Particles and Rotational Motion

Case study·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 uniform disc turntable of mass

3\text{ kg}

and radius

0.40\text{ m}

carries a

1\text{ kg}

small object stuck at its rim. The system rotates about the symmetry axis of the disc. A torque of

0.80\text{ N m}

is then applied.

Total: 5 marks

(a) Find the moment of inertia of the disc alone. (1 mark)

(b) Find the total moment of inertia of the disc-object system. (1 mark)

(d) Find the angular acceleration produced by the torque. (1 mark)

(e) Find the rotational kinetic energy when $\omega=5\text{ rad s}^{-1}$ . (1 mark)

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

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