Which of the following type of wheels of same mass and radius will have largest moment of inertia?

Which of the following type of wheels of same mass and radius will have largest moment of inertia?
  1. Ring
  2. Angular disc
  3. Solid disc
  4. Cylindrical disc

Solution

A wheel is rotated about its central axis, therefore we will compare all the moments of inertia of various shapes about their central axis.

Moment of Inertia of Ring of mass M and radius R about its central axis is MR2

Moment of inertia of solid disc of M and radius R about its central axis is MR22

Moment of inertia of the annular disc of mass M with outer radius R and inner outer radius r about its central axis is MR2+r22

Moment of inertia of the cylindrical disc or hollow cylinder of mass M with outer radius R and inner outer radius r about its central axis is MR2+r22

Hence, from the above expressions of moment of inertia of given shapes, it is clear that moment of inertia of ring is maximum for the given mass and same radius.

Asked in: AP EAMCET 2021 (19 Aug Shift 1)

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