Question

5. The moment of inertia of a solid sphere about
an axis passing through its centre is 0.8kgm.
The moment of inertia of another solid sphere
whose mass is same as mass of first sphere,
but the density is 8 times density of first
sphere, about an axis passing through its
centre is
1) 0.1kgm? 2) 0.2 kgm?
3) 0.4 kgm? 4) 0.5 kgm?​

Answer 1

I1 = 2/5 M(R1)^2 = 0.8 kg-m

2/5 d.V1(R1) ^2 = 0.8

d.V

I2 = 2/5( 8.d) V2 (R2)^2

I1/I2 =( V1 R1^2 ) / (8V2.R2^2)

Taking radius = constant

So that V1 = V2

I1/I2 = 1/8

I1/8 = I2

I2 = 0.1 kg-m

Regards