2. [0/4 Points] PREVIOUS ANSWERS ASK YOUR TEACHER A disk with moment of inertia 11 rotates about a frictionless, vertical axle with angular speed all. A second disk, this one having moment at inertia [2 and initially not rotating, drops ontn the first disk (figure). Because of frittion between the surfaces, the two eventually reach the same angular speed (OF l Before After (a) Calculate wf. (Use the following as necessary: I1, [2, (9,.) (of: X (l3) Calculate the ratio of the nal to the initial rotational energy. (Use the following as necessary 11, 12, mi.) 3. [-/3 Points] DETAILS MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A student sits on a freely rotating stool holding two dumbbells, each of mass 2.97 kg (see figure below). When his arms are extended horizontally (Figure a), the dumbbells are 0.95 m from the axis of rotation and the student rotates with an angular speed of 0.745 rad/s. The moment of inertia of the student plus stool is 2.55 kg . m and is assumed to be constant. The student pulls the dumbbells inward horizontally to a position 0.292 m from the rotation axis (Figure b). w; a b (a) Find the new angular speed of the student. rad/s (b) Find the kinetic energy of the rotating system before and after he pulls the dumbbells inward. Kbefore = Kafter =