Practice question
Question
A torque of 20Nm acts on a wheel with moment of inertia 10kg m2 starting from rest. What is its angular speed after 4s?
Explanation
α = τI = 2010 = 2rad/s2. ω = ω0+αt = 0+2×4 = 8rad/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 8 rad/s. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.