Question

The densitis of two solid spheres A and B of the same radii R very with radial distance `r as p_A(r ) = k ((r )/(R )) and p_B(r ) = k((r )/(R )^5,` respectively, where k is a constant . The moments of inertia of the inividual spheres about axes passing throgh their centres are `I_A and I_B` respectively. if `(I_B)/(I_A) = (n)/(10),` the value of n is

Answer 1

Correct Answer - 6
`I=int2/3rho4pir^(2)r^(2)dr`
`I_(A)propint(r)(r^(2))(r^(2))dr`
`I_(B)propint(r^(5))(r^(2))(r^(2))dr`
`:. (I_(B))/(I_(A))=6/10`