HARD
JEE Main/Advance
IMPORTANT
Earn 100

A uniform thin rod of length L is hinged about one of its ends and is free to rotate about the hinge without friction. Neglect the effect of gravity.A force F is applied at a distance x from the hinge on the rod such that force is always perpendicular to the rod. Find the normal reaction at the hinge as function of x, at the initial instant when the angular velocity of rod is zero.

Question Image  

Important Questions on Rotational Mechanics

HARD
JEE Main/Advance
IMPORTANT

A solid cylinder of mass M=1 kg & radius R=0.5 m is pivoted at its centre & has three particles of mass m=0.1kg mounted at its perimeter in the vertical plane as shown in the figure. The system is initially at rest. Find the angular speed of the cylinder, when it has swung through 900 in anticlockwise direction. [Take g=10 m s-2]

Question Image

HARD
JEE Main/Advance
IMPORTANT

A rigid body is made of three identical uniform thin rods each of length L fastened together in the form of letter H. The body is free to rotate about a fixed horizontal axis AB that passes through one of the legs of the H. The body is allowed to fall from rest from a position in which the plane of H is horizontal. What is the angular speed of the body, when the plane of H is vertical. 

Question Image

MEDIUM
JEE Main/Advance
IMPORTANT

A uniform rod of mass m and length L lies radially on a disc rotating with angular speed ω in a horizontal plane about its axis. The rod does not slip on the disc and the centre of the rod is at a distance R from the centre of the disc. Find out the kinetic energy of the rod.

Question Image

MEDIUM
JEE Main/Advance
IMPORTANT

The moment of inertia of the pulley system as shown in figure is 3 kgm2 . Its radius is 1m. The system is released from rest ,find the linear velocity of the block when it has descended through 40 cm. (Assume that there is no slipping between string & pulley and string is light) [Take g=10 m s-2 ]

Question Image   

MEDIUM
JEE Main/Advance
IMPORTANT
A particle having mass 2 kg is moving with velocity (2i^+3j^) m s-1. Find angular momentum of the particle about origin when it is at (1, 1, 0). 
MEDIUM
JEE Main/Advance
IMPORTANT
A particle having mass 2 kg is moving along a straight line 3x + 4y = 5 with speed 8 m s-1. Find angular momentum of the particle about the origin, x & y are in meters. 
MEDIUM
JEE Main/Advance
IMPORTANT

Two beads (each of mass m) can move freely in a frictionless wire whose rotational inertia with respect to the vertical axis is I. The system is rotated with an angular velocity ω0 when the beads are at a distance r2 from the axis. What is the angular velocity of the system when the beads are at a distance r from the axis ?

Question Image  

MEDIUM
JEE Main/Advance
IMPORTANT
A system consists of two identical small balls of mass 2 kg each connected to the two ends of a 1 m long light rod. The system is rotating about a fixed axis through the centre of the rod and perpendicular to it at an angular speed of 9 rad s-1. An impulsive force of average magnitude 10 N acts on one of the masses in the direction of its velocity for 0.20 s. Calculate the new angular velocity of the system.