Student Login

Home›Chapters›Rotational Motion PYQs›Moment of Inertia & Radius of Gyration›Question 109

MHT CET 2023 (10 May, Shift 1) · Moment of Inertia & Radius of Gyration

Moment of Inertia & Radius of Gyration question from MHT CET 2023 (10 May, Shift 1)

Q109MHT CET 2023 · 10 MAY · SHIFT 1Difficult

Moment of Inertia & Radius of Gyration

Seven identical discs each of mass $M$ and radius $R$ are arranged in a hexagonal plane pattern so as to touch each neighbour disc as shown in the figure. The moment of inertia of the system of seven discs about an axis passing through the centre of central disc and normal to the plane of all discs is

Show answer and solution

Answer: (d)

Central disc: $\frac{MR^2}{2}$ .
Each outer disc centre is $2R$ away: $\frac{MR^2}{2} + 4MR^2 = \frac{9}{2}MR^2$ .
$I = \frac{1}{2}MR^2 + 6 \times \frac{9}{2}MR^2 = \frac{55}{2}MR^2$
So the answer is (d).

Report a mistake

More questions on Moment of Inertia & Radius of Gyration

A uniform solid cylinder with radius R and length L has moment of inertia I 1, about the…JEE Main 2023 (24 Jan, Shift 2)
The ratio of the radius of gyration of a thin uniform disc about an axis passing through…NEET 2022 (Phase 1)
Four identical discs each of mass ' M ' and diameter ' a ' are arranged in a small plane…JEE Main 2022 (28 Jul, Shift 1)
Four particles with a mass of 1 kg, 2 kg, 3 kg and 4 kg are situated at the corners of a…JEE Main 2022 (30 Jun, Shift 1)
Match List-I with List-II Choose the correct answer from the options given below: List-I…JEE Main 2022 (28 Jun, Shift 1)
The radius of gyration of a cylindrical rod about an axis of rotation perpendicular to…JEE Main 2022 (26 Jul, Shift 2)
Moment of Inertia (M.I.) of four bodies having same mass 'M' and radius '2R' are as…JEE Main 2022 (25 Jun, Shift 2)
The moment of inertia of a uniform thin rod about a perpendicular axis passing through…JEE Main 2022 (29 Jun, Shift 2)