Question

Two uniform solid spheres, A and B have the same mass. The radius of sphere B is twice that of sphere A. The axis of rotation passes through the center of each sphere. Which one of the following statements concerning the moments of inertia of these spheres is true?

a. The moment of inertia of A is one-fourth that of B
b. The moment of inertia of A is one-half that of B
c. The moment of inertia of A is 5/4 that of B
d. The moment of inertia of A is 5/8 that of B
e. The two spheres have equal moments of inertia

Answer 1

I = 2/5 M R^2 for solid sphere

IA = 2/5 M R^2

IB = 2/5 M (2 R)^2

IB / IA = 4

a. Sphere A has 1/4 the inertia of sphere B.