1. When sliding down to a height h, superimpose the change in velocity in the vertical direction over this period of time with the initial velocity vector, and then superimpose this relative velocity with the vector of the implicit velocity (inclined plane velocity)
2. This moment of inertia is very basic.
3. (1) Find the definite integral.
(2) Use the answer above and come out with the kinetic energy theorem.
(3) Yes. According to the loop theorem (the chapter on curve integrals), it satisfies the conservative force condition.