Where do you find the time, Mike? - I had just pulled the physics book down off the shelf and figured out the exact same thing. You keep beating me to the punch.
If Ip is the Inertia through the point of contact (i.e. the instaneous axis of rotation) then the parallel axis theorem tells us that
Ip = Icm + m r^2
Where Icm is the rotational inertia of the wheel through the axle,
m is the mass of the translating body, and
r is the distance from the axle to the point of contact.
And simply, KE = 1/2 Ip w^2.
I simply tried to add Icm + m, forgetting the r^2. (fortunately, I'd just happened to have picked r=1.08, so my error wasn't too large!
)
Thanks for the catch, it's nice to be kept honest.
