Question

A disc of mass \(M\) and radius \(R\) has a concentric hole of radius \(R/2\). Its moment of inertia about an axis passing through its center and perpendicular to its plane is:

• A. \(\dfrac{15}{32}MR^2\)
• B. \(\dfrac{13}{32}MR^2\)
• C. \(\dfrac{5}{16}MR^2\)
• D. \(\dfrac{3}{8}MR^2\)

Hint:

For an annular disc: \[ I=\frac12 M(R_1^2+R_2^2) \] where: \[ R_1=\text{inner radius} \] \[ R_2=\text{outer radius} \] This formula is extremely important for rotational motion problems.

Answer 1

The Correct Option is B