Final angular velocity of a disk under torque

Practice question

Question

A disk with moment of inertia 1.5kg m2 rotates at 4rad/s. A torque of 6Nm acts for 3s. What is its final angular velocity?

Options

Choose one · Correct answer highlighted

12 rad/s 14 rad/s 16 rad/s Correct 18 rad/s

Explanation

α = τI = 61.5 = 4rad/s2. Δω = αt = 4×3 = 12rad/s. ω = ω0+Δω = 4+12 = 16rad/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 16 rad/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

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