Verified Solution • 2025–26 Session moderate

QAIPMT-2010-Ph-1980: NEET 2010 Physics - Class 11 AIPMT-2010-Ph-1980 Solution: From a circular disc of radius R and mass 9M, a small disc of…

From a circular disc of radius R and mass 9M, a small disc of mass M and radius

R/3

is removed concentrically. The moment of inertia of the remaining disc about an axis perpendicular to the plane of the disc and passing through its centre is

Multiple Choice Options

A $\frac{40}{9}MR^2$
B $MR^2$
C $4MR^2$
D $\frac{4}{9}MR^2$

Step-by-Step Verified Solution

Mass of the disc = 9M Mass of removed portion of disc = M The moment of inertia of the complete disc about an axis passing through its centre O and perpendicular to its plane is I 1 = 9 2 M R 2 Now, the moment of inertia of the disc with removed portion I 2 = 1 2 M ( R 3 ) 2 = 1 18 M R 2 Therefore, moment of inertia of the remaining portion of disc about O is I = I 1 _ I 2 = 9 2 M R 2 _ M R 2 18 = 40 M R 2 9

Related Learning Resources & Exam Preparation

NEET PYQ Question Bank

Browse year-wise authentic previous years' questions with solutions

Authentic CBT Mock Tests

Simulate official exam environment with live timer and percentile scoring