JEE Main | 2018Rotational MotionEasy

Question

Seven identical circular planar disks, each of mass M and radius R are welded symmetrically as shown. The moment of inertia of the arrangement about the axis normal to the plane and passing
through the point P is :
 

Options

A.

552MR2

B.

732MR2

C.

1812MR2

D.

192MR2

Solution


I0 = Icm + md2
=7MR22+ 6(M×(2R)2) = 55MR22
Ip = I0 + md2 
=55MR22+7M (3R)2=1812MR2

Create a free account to view solution

View Solution Free
Topic: Rotational Motion·Practice all Rotational Motion questions

More Rotational Motion Questions

Off two eggs which identical sizes, shapes and weights, one is raw and the other is half - billed. The ratio between the...A solid sphere of mass M, radius R and having moment of inertia about an axis passing through the centre of mass as I, i...In the adjoining figure along which axis the moment of inertia of the triangular lamina will be maximum- [Given that AB ...A disc of radius R/2 is cut from a uniform disc of radius R as shown in the figure. The mass of the disc (with cavity) i...Two bodies A and B having same angular momentum and IA > IB, then the relation between (K.E.)A and (K.E.)B will be : ...