Ok, so:
I before collision = (1/2 m r^2 + 1/2 MR^2) + [(m+M) * (R+r)]
then
I after collision = (1/2 m r^2 + 1/2 MR^2) + [(m+M) * 0.034925 m]
which 0.034925 m is the center of mass of part a, am I right?
so KEafter collision = .5mv2^2 + .5Iw^2
and KEbefore collison = .5mv1^2 + .5Iw^2
then set it to equal:
.5mv2^2 + .5Iw^2 = .5mv1^2 + .5Iw^2 (why are they equal?)
with I = 1/2 m r^2 + 1/2 MR^2
Am I on the right track?
Thanks so much for your patience ;)