MEDIUM
JEE Main/Advance
IMPORTANT
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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 ?

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Important Questions on Rotational Mechanics

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. 
HARD
JEE Main/Advance
IMPORTANT
A uniform round board of mass M and radius R is placed on a fixed smooth horizontal plane and is free to rotate about a fixed axis which passes through its centre. A man of mass m is standing on the point marked A on the circumference of the board. At first, the board and the man are at rest. The man starts moving along the rim of the board at constant speed v0 relative to the board. Find the angle of board’s rotation when the man passes his starting point on the disc first time.
MEDIUM
JEE Main/Advance
IMPORTANT

A point object of mass m moving horizontally hits the lower end of the uniform thin rod of length l and mass m and sticks to it. The rod is resting on a horizontal, frictionless surface and pivoted at the other end as shown in figure.

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Find out angular velocity of the system just after collision.

MEDIUM
JEE Main/Advance
IMPORTANT

The centre of mass of a uniform rod of length 10 meter is moving with a translational velocity of 50 m s-1 on a frictionless horizontal surface as shown in the figure and the rod rotates about its centre of mass with an angular velocity of 5 rad s-1. Find out velocities vA and vB.

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MEDIUM
JEE Main/Advance
IMPORTANT

A ring of radius 1 m performs combined translational and rotational motion on a frictionless horizontal surface with an angular velocity of 3 rad s-1 as shown in the figure. Find out velocity of its centre and point A, if the velocity of the lowest point vP is 1 m s-1.

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EASY
JEE Main/Advance
IMPORTANT

A plank is moving with a velocity of 4 m s-1. A disc of radius 1 m rolls without slipping on it with an angular velocity of 3 rad s-1 as shown in the figure. Find out the velocity of centre of the disc.

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MEDIUM
JEE Main/Advance
IMPORTANT

The end B of uniform rod AB which makes angle θ with the floor is being pulled with a velocity v0 as shown. Taking the length of the rod as l, calculate the following at the instant when θ= 37º

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 (a) The velocity of end A 

(b) The angular velocity of rod

(c) Velocity of CM of the rod.

HARD
JEE Main/Advance
IMPORTANT

A ball of radius R=10.0 cm rolls without slipping on a horizontal plane so that its centre moves with constant acceleration a=2.50 cm s-2; t=2.00 s after the beginning of motion, its position corresponds to that shown in the figure. Find: 

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(a) the velocities of the points A, B and O 

(b) the accelerations of these points.