A solid disk, which has a radius of 0.070 m and a mass of 0.88 kg, is rotating with an angular frequency of 12 rad/s about an axis perpendicular to its center. A thin ring, which has a radius of 0.040 m and a mass of 1.8 kg, is dropped straight down onto the disk so that they are concentric and rotating together. (Note: The ring is not rotating before the collision.)
a. What is the moment of inertia of the disk before the collision?
b. What is the moment of inertia of the disk and ring system after the collision?
c. What is the angular frequency of the system after the collision? Assume that the system is isolated so that angular momentum is conserved.