A disc with moment of inertia I₁ = 40 kg.m² and angular velocity $\omega$₁ = 20 rad/s is dropped on to a stationary second disc along the axis of rotation.The second disc has moment of inertia I₂ = 60 kg.m².What is the angular velocity of the two discs? A)4 rad/s B)6 rad/s C)8 rad/s D)12 rad/s E)20 rad/s

Question

Quizplus · Accepted Answer

The conservation of angular momentum states that the initial angular momentum equals the final angular momentum. Thus, I₁ω₁ = (I₁ + I₂)ω_final. Solving for ω_final gives ω_final = (I₁ω₁) / (I₁ + I₂) = (40 * 20) / (40 + 60) = 8 rad/s.

A Disc with Moment of Inertia I1 = 40 Kg ω\omegaω

A Disc with Moment of Inertia I₁ = 40 Kg $\omega$