Chapter 11 – Rotational Mechanics

ABC is an equilateral triangle with O as its centre. vector F1,F2 and F3 three forces acting along the sides AB, BC and AC respectively. If the total torque about O is zero then the magnitude of vector F3 is ABC is an equilateral triangle with O as its centre. vector F1 BC and AC [...]

A rod PQ of mass M and length L is hinged at end P. The rod is kept horizontal by a massless string tied to point Q as shown in figure. When string is cut, the initial angular acceleration of the rod is A rod PQ of mass M and length L is hinged at [...]

A solid cylinder of mass 50 kg and radius 0.5 m is free to rotate about horizontal axis. A massless string is wound round the cylinder with one end attached to it and other hanging freely. Tension in the string required to produce an angular acceleration of 2 revolutions s^−2 is :- A disc of [...]

An automobile moves on a road with a speed of 54 km/h^−1. The radius of its wheel is 0.45 m and the moment of inertia of the wheel about its axis of rotation is 3 kg/m^2. If the vehicle is brought to rest in 15 s, the magnitude of average torque transmitted by its brakes [...]

A solid sphere is in rolling motion. In rolling motion a body prossesses translational kinetic energy (Kt) as well as rotational kinetic energy (Kr) simultaneously. The ratio Kt: (Kt + Kr) for the sphere is The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from [...]

A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has speed of 20 cm/s. How much work is needed to stop it ? A disc of radius 2 m and mass 100 kg rolls on a horizontal floor. Its centre of mass has speed of [...]

A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere? The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing [...]

Two bodies have their moments of inertia I and 2I respectively about their axis of rotation. If their kinetic energies of rotation are equal, their angular momenta will be in the ratio. their angular momenta will be in the ratio. Two bodies have their moments of inertia I and 2I respectively about their axis of [...]

The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of the disc and normal to the disc is : The moment of inertia of a uniform circular disc of radius R and mass M about an axis passing from the edge of [...]

The ratio of the radii of gyration of a circular disc to that of a circular ring, each of same mass and radius, around their respective axis is : around their respective axis is : each of same mass and radius The ratio of the radii of gyration of a circular disc to that of [...]