Well, in the detailed answer Krotov has ignored Kinetic energy due to rotational motion completely.His final equation is
mv^2/2 = mV^2/2 - mgr(1-cosx).
Anyways, moment of inertia of solid cylinder and disk are same
Homework Statement
I have attatched both the problems. The figure is essentially the same.
Homework Equations
1. Energy conservation
2.mgcosx - N = mv^2/r , where N is zero in limiting case.
The Attempt at a Solution
I solved the whole question and got the answer given in irodov(0.33...