Consider two uniform solid spheres where both have the same diameter, but one has twice the mass of the other. The ratio of the larger moment of inertia to that of the smaller moment of inertia is
A) 8.
B) 4.
C) 6.
D) 2.
E) 10.

Question

Quizplus · Accepted Answer

The moment of inertia (I) of a solid sphere about its axis is given by $I = \frac{2}{5}MR^2$, where M is the mass and R is the radius. Since both spheres have the same diameter (and thus the same radius), and one sphere has twice the mass of the other, the moment of inertia of the heavier sphere will be twice that of the lighter sphere, because the moment of inertia is directly proportional to the mass when the radius is constant.

Consider Two Uniform Solid Spheres Where Both Have the Same