The angular momentum L = I ω for a disk with I = 0.09 kg·m^2 and ω = 20 rad/s. What is L?

• A. 0.9 kg·m^2/s
• B. 1.0 kg·m^2/s
• C. 1.8 kg·m^2/s
• D. 2.7 kg·m^2/s

Answer: (C)

Angular momentum of a rotating object is found from L = I ω, the product of its moment of inertia and its angular velocity. With I = 0.09 kg·m^2 and ω = 20 rad/s, multiply: L = 0.09 × 20 = 1.8 kg·m^2/s. The units work out as kg·m^2/s, confirming the result. So the angular momentum is 1.8 kg·m^2/s.