Two cylinders have the same mass and radius. One is hollow and

two-cylinders-have-the-same-mass-and-radius-one-is-hollow-and

Two cylinders have the same mass and radius. One is hollow and the other is solid. Which one will have the greater moment of inertia about the central axis?

A. Hollow cylinder

B. Solid cylinder

C. Same for both

D. Depends on length of cylinder

The question was asked in an online interview.

I need to ask this question from Moment of Inertia in chapter System of Particles and Rotational Motion of Physics – Class 11

Right choice is A. Hollow cylinder

Easy explanation: The hollow one will have greater density as both have the same mass and it has to be distributed uniformly. Thus, the summation of product of mass and perpendicular distance from the axis squared of each particle will be more for the hollow cylinder. And hence, it has more moment of inertia.