Moment of Inertia
Moment of Inertia: Overview
This topic covers concepts, such as, Theorem of Parallel Axes, Theorem of Perpendicular Axes, Radius of Gyration & Moment of Inertia of Hollow Cylinder etc.
Important Questions on Moment of Inertia
How to calculate the moment of inertia from any axis?

From a triangular lamina of side a and mass , a small triangular Lamina made by joining mid-points of sides of triangular lamina is cut. If Moment of Inertia of complete Lamina about COM is and Moment of Inertia of remaining Lamina about centroid is , then find the value of .

A half section of pipe of mass and radius rests on a rough horizontal surface. Now a vertical force is applied as shown. Assuming that the section rolls without sliding. Then [Centre of mass of half ring is below the centre]

There is a uniform solid hemisphere. On its upper plane and axis are drawn which are mutually perpendicular to the upper plane and passing through the centre . If moment of inertia of the hemisphere about and -axis are and respectively then:

Four point masses each of mass are arranged in the plane. The moment of inertia of this array of masses about -axis is


A solid sphere, a thin ring and a cylinder of same mass and radius, held at rest are released simultaneously to roll down on an inclined plane. Which one will reach the bottom first?

Point masses and are lying at the points and , respectively. The moment of inertia of this system about the -axis will be,

Four similar point masses (each of mass ) are placed on the circumference of a disk of mass and radius . The moment of inertia of the system about the normal axis through the center will be,

On the marks of and of a light meter scale, two weights, and , respectively, are placed. The moment of inertia (in ) about the vertical axis through the mark will be,


M.O.I. of a disc is minimum about an axis

The parallel axis theorem uses the _____ of the distance.

Four hollow spheres, each with a mass of and a radius are connected with massless rods to form a square with side of length 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 for the two cases.

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

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

A solid cylinder is made of radius R and height 3R having mass density . Now two half spheres of radius R are removed from both ends. The moment of inertia of remaining portion about axis ZZ' can be calculated as . Find K.

A uniform thin bar of mass and length meter is bent to make an equilateral hexagon. The moment of inertia about an axis passing through the centre of mass and perpendicular to the plane of hexagon is ________

A closed cylindrical container is partially filled with water. As the container rotates in a horizontal plane about a perpendicular, its moment of inertia

The inductance in a coil plays the same role as
