For 9 apply conservation of energy
little weak at rotation can you send the solution please @Achyut_2020
Now solve it put v=wR/2
As work done by friction and normal force will be zero
If not understood ,let me know
Question 9 is a ncert question or sl arora book question if you have it you can check it
Question 8 Option A
You can place region 1 in region 2 moment of inertia of systen still wont same.
Regarding question 9 it came in IITJEE.
I gave given this paper but this question is a ncert question so i don't remember ncert but students who follow ncert remember these questions
Got it .Thanks guys.