# A horizontal plane supports a fixed vertical cylinder of radius and a particle is attached to the cylinder by a horizontal thread as shown in Fig. The particle initially rest on a horizontal plane. A horizontal velocity is imparted to the particle, normal to the threading during subsequent motion.Point out the false statement a) Angular momentum of particle about remains constant b) Angular momentum about remains constant c) Momentum and kinetic energy both remain constant d) Kinetic energy remains constant

## Question ID - 100655 :- A horizontal plane supports a fixed vertical cylinder of radius and a particle is attached to the cylinder by a horizontal thread as shown in Fig. The particle initially rest on a horizontal plane. A horizontal velocity is imparted to the particle, normal to the threading during subsequent motion.Point out the false statement a) Angular momentum of particle about remains constant b) Angular momentum about remains constant c) Momentum and kinetic energy both remain constant d) Kinetic energy remains constant

3537

 (a,b,c) Weight of the particle is balanced by normal reaction of the floor. Hence, the resultant force acting on the particle is provided by the tension in the thread The line of acting of this tension passes through Hence, the tension produces a momentabout . It means, angular momentum about does not remain conserved. The tension always produces a moment about . Magnitude of this moment is equal to in an anticlockwise direction. Hence, options (a), (b) and (c) are incorrect. Since neither external work is done on the particle nor energy is lost against friction, therefore KE of the ball remains constant. Hence, option (d) is correct
 A uniform chain of length and mass is lying on a smooth table and one–third of its length is hanging vertically down over the edge of the table. If is the acceleration due to gravity, the work required to pull the hanging part on to the table is a) b) c) d)  