Q.

From a circular of mass 'M' and radius 'R' an arc corresponding to a 90° sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is 'K' times 'MR2'. Then the value of 'K' is              [2021]
 

1 18  
2 34  
3 78  
4 14  

Ans.

(2)

Here: M is the mass and R is the radius of the ring.

Moment of inertia of a ring, I=MR2

If 90° sector is removed, the moment of inertia of the remaining part of the ring is

I=MR2-MR24  KMR2=34MR2

Here   K=34