A object which is rotating around a horizontal axis is placed on a surface, and starts sliding (with kinetic friction). After some time, it starts rolling without sliding through the table.
The goal is to determine the disk's angular velocity once it starts rolling and the time it takes to do so.
(Notes: When the disk is rolling, we have that $v = w.r$. We can also assume that the kinetic friction has the same direction as the motion, and therefore contributes to the increase in velocity of the mass center over time.)
After-solving I noticed that the expression for $w$ doesn't depend on friction at all. Why is that?