A wheel of radius 0.20 m rotates freely about its centre. A string wrapped around its rim is pulled tangentially with a force of 10 N, producing an angular acceleration of 2 rad/s². Find the moment of inertia of the wheel in kg m².

Question

G1 Physics · Accepted Answer

The applied torque is τ = Fr, because the force is tangential. Given F = 10 N, r = 0.20 m. Thus τ = 10×0.20 = 2 N m. Using rotational dynamics, τ = Iα. Therefore, I = τ/α = 2/2 = 1 kg m². Answer: 1.