Question

$3
2. What didn't Manu and Myna have a
choice about?​

Answer 1

Answer:

According to perpendicular axis theorem, IZ=IX+IY

We know that IX=IY due to the geometrical symmetry of  

the disc, where IX and IY are M.I. of the disc  about an axis passing through its diameter.

⇒ IZ=IX+IY ⇒IX=IY=2IZ

Where, IZ=ML of the disc about Z−axis passing through  

its Centre perpendicular to its plane =mr2/2

∴M.I. about diameter =IX=IY = 41MR2