Physics · 2019
JEE Main · 10 April 2019, Shift 1 · Q7
A thin disc of mass M and radius R has mass per unit area σ( r )= kr^2 where r is the distance from its centre. Its moment of inertia about an axis…
A thin disc of mass $\displaystyle M$ and radius $\displaystyle R$ has mass per unit area $\displaystyle \sigma(\mathrm{r})=\mathrm{kr}^2$ where r is the distance from its centre. Its moment of inertia about an axis going through its centre of mass and perpendicular to its plane is :
Official answer
(2)
$\displaystyle \frac{2 \mathrm{MR}^2}{3}$
More from Rotational Motion
- The moment of inertia of a circular ring of mass M and diameter r about a tangential axis lying in the plane of the ring is:2025
- A solid sphere of mass M and radius R is divided into two unequal parts. The first part has a mass of (7 M)/8 and is converted into a uniform disc of…2019
- A string is wrapped around the rim of a wheel of moment of inertia 0.40 kgm^2 and radius 10 cm. The wheel is free to rotate about its axis. Initially…2024
- An object of mass 8 kg is hanging from one end of a uniform rod CD of mass 2 kg and length 1 m pivoted at its end C on a vertical wall as shown in…2023
- A solid sphere (A) of mass 5 m and a spherical shell (B) of mass m, both having same radius, are placed on a rough surface. When a force of same…2026
- A solid spherical ball is rolling on a frictionless horizontal plane surface about its axis of symmetry. The ratio of rotational kinetic energy of…2022
- A ring and a solid sphere roll down the same inclined plane without slipping. They start from rest. The radii of both bodies are identical and the…2024
- Moment of inertia of a square plate of side l about the axis passing through one of the corner and perpendicular to the plane of square plate is…2021
JEE Main 2019 Physics question, with the answer from NTA’s final answer key. Where our answers come from.