Moment of Inertia and Axes Theorems

IMPORTANT

Moment of Inertia and Axes Theorems: Overview

This topic covers concepts such as Moment of Inertia of Ring, Moment of Inertia of Uniform Rod, Moment of Inertia of Circular Disc, Moment of Inertia of Cylinder, Moment of Inertia of a Spherical Shell, Moment of Inertia of Sphere, etc.

Important Questions on Moment of Inertia and Axes Theorems

EASY
IMPORTANT

Find the moment of inertia of a uniform annular disc of mass 100 gm having an inner radius 10 cm and outer radius 20 cm about an axis passing through its centre and perpendicular to its plane.

MEDIUM
IMPORTANT

Derive an expression for the moment of inertia of an annular disc having mass M  about an axis passing through it centre and perpendicular to it

MEDIUM
IMPORTANT

Calculate the moment of inertia of an annular disc about an axis which lies in the plane of the disc and tangential to the outer circle. The mass of the disc is M and its inner radius is R2 and outer radiusR1 .

MEDIUM
IMPORTANT

The moment of inertia of an annular disc of mass M, outer and inner radii R and r, about its diameter is :

HARD
IMPORTANT

Four hollow spheres, each with a mass of 1 kg and a radius R=10cm, are connected with massless rods to form a square with side of length L=50 cm, In case-1, the masses rotate about an axis that bisects two sides of the square. In case- 2, the masses rotate about an axis that passes through the diagonal of the square, as shown in the figure. Compute the ratio of the moments of inertia I1/I2, for the two cases.

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EASY
IMPORTANT

The distance in the parallel axis theorem is multiplied by _____.

MEDIUM
IMPORTANT

The moment of inertia of a hollow cubical box of mass M and side length a, about an axis passing through centres of two opposite faces, is equal to xMa218. The value of x is

MEDIUM
IMPORTANT

The moment of inertia of a hollow cubical box of mass M and side length a, about an axis passing through centres of two opposite faces, is equal to xMa218. The value of x is

HARD
IMPORTANT

A circular disc A of radius r is made from an iron plate of thickness t and another circular disc B of radius 4 r is made from an iron plate of thickness t 4. What is the relation between the moments of inertia of IA and IB?

EASY
IMPORTANT

The moment of inertia of a thin rod of length L and mass M about an axis passing through a point at a distance L3 from one of its ends and perpendicular to the rod is,

EASY
IMPORTANT

A thin wire of length L and uniform linear mass density ρ is bent into a circular loop with centre O as shown. The moment of inertia of the loop about the axis XX' will be,

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MEDIUM
IMPORTANT

Three solid spheres of mass M and radius R are shown in the figure. The moment of inertia of the system about xx' axis will be,

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EASY
IMPORTANT

The moment of inertia of a circular ring about an axis passing through its centre and perpendicular to its plane is 200 g cm2. If the radius of the ring is 5 cm, find the mass of the ring.

HARD
IMPORTANT

A lamina is made by removing a small disc of diameter 2R from a bigger disc of uniform mass density and radius 2R, as shown in the figure. The moment of inertia of this lamina about axes perpendicular to the plane of the lamina and passing through the points O and P is IO and IP​ respectively. If the ratio IPIO=mn, where m and n are the smallest integers, then what is the value of m+n?

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MEDIUM
IMPORTANT

A uniform cylinder has a radius R and length L. If the moment of inertia of this cylinder about an axis passing through its centre and normal to its circular face is equal to the moment of inertia of the same cylinder about an axis passing through its centre and perpendicular to its length, then

HARD
IMPORTANT

A lamina is made by removing a small disc of diameter 2R from a bigger disc of uniform mass density and radius 2R, as shown in the figure.The moment of inertia of this lamina about axes passing though O and P is IO and IP​ respectively. Both of these axes are perpendicular to the plane of the lamina.The ratio IP / IO to the nearest integer is 

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MEDIUM
IMPORTANT

The moment of inertia of a solid sphere of mass M and radius R about a tangent to the sphere is _____MR2(Write the answer upto one decimal place).

HARD
IMPORTANT

State and prove principle of perpendicular axes.

HARD
IMPORTANT

State and prove principle of parallel axes.

HARD
IMPORTANT

A thin uniform rod of length 1 m and mass 1 kg is rotating about an axis passing through its centre and perpendicular to its length. Calculate the moment of inertia and radius of gyration of the rod about an axis passing through a point midway between the centre and its edge, perpendicular to its length.