Question

Moment of inertia of a uniform circular disc about a diameter is I. Its moment of inertia about an axis perpendicular to its plane and passing through a point on its rim will be

• A. 5I
• B. 3I
• C. 6I
• D. 4I

Answer 1

Answer: (C)

6I

Answer 2

Moment of inertia of uniform circular disc about diameter = I According to theorem of perpendicular axes. Moment of inertia of disc about axis = $2I=\frac{1}{2}mr^2$ Applying theorem of parallel axes Moment of inertia of disc about the given axis = 2I + mr$^2$ = 2I + 4I = 6I.