1. The problem statement, all variables and given/known data A uniform disk is set into rotation with an initial angular speed about its axis through its center. While still rotating at this speed, the disk is placed in contact with a horizontal surface and released. What is the angular speed of the disk once pure rolling takes place (in terms of omega final and initial)? 2. Relevant equations 1/2mv(int)^2 + 1/2Iw(int)^2 = 1/2mv(final)^2 + 1/2Iw(final)^2 Torque=d(L)/d(t) Normal Force=mg I=1/2mr^2 L=Iw 3. The attempt at a solution I knew that the only once a disk rolls without slipping does w=v/r I simplified the first equation as follows: v(int)^2 + 1/2r^2w(int)^2 = v(final)^2 + 1/2v(final)^2 v(int)^2 + 1/2r^2w(int)^2 = 3/2v(final)^2 I also knew that the only force acting on the disk was the surface. So I knew that Fr= d(L)/d(t) mgr=[w(final)I-w(int)I]/d(t) from there I got that g=[r(w(final)-w(int))]/2d(t) I really have no idea where to go from here though. Any push in the right direction would be appreciated! Thanks!