Question

The two spheres, one of which is hollow and other
solid, have identical masses and moment of inertia
about their respective diameters. The ratio of their
radii is given by
(1) 5:7
(2) 3:5
(3) 13:15
(4) 3:7​

Answer 1

QUESTION:-

The two spheres, one of which is hollow and other

solid, have identical masses and moment of inertia

about their respective diameters. The ratio of their

radii is given by

(1) 5:7

(2) 3:5

(3) 13:15

(4) 3:7

SOLUTION:

2mr(1)^2/3[equation 1]

the moment of inertia of solid sphere along diameter is =2mr(2)^2/5 [equation 2]

Given that both the moment of inertia are equal. on equating equation 1 and 2, we get

r(1)^2/r(2)^2 = 3/5

hence r(1)/r(2) = √3/√5.