Final answer:
The conservation of angular momentum indicates that the disk's rotation rate will increase as the mass moves toward the center. However, without explicit calculations based on the moment of inertia before and after the shift, we cannot determine the exact final rotation rate.
Step-by-step explanation:
The student's question regarding the final rotation rate of a disk involves the concept of the conservation of angular momentum. In this scenario, we have a disk of mass 2.0 kg and radius 60 cm, with a small mass of 0.05 kg attached at the edge rotating at 2.0 rev/s. As the small mass slides gradually to the center of the disk, the system's angular momentum is conserved. As a result, the final rotation rate will increase since the moment of inertia of the system decreases when the mass moves closer to the axis of rotation.
The possible answers provided refer to how the disk's rotation rate will change, with options suggesting it will either speed up or slow down. However, without additional details like the moment of inertia for both initial and final states, we cannot reliably determine the precise final rotation rate from the provided options. The conservation of angular momentum dictates that if the mass distribution of an object becomes more concentrated toward its axis of rotation, its rotation rate will increase to conserve angular momentum, but we would need to compute the moments of inertia and equate the initial and final angular momenta to find the exact answer.