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The angular velocity ω and the angular acceleration α are plotted with time as shown. Which of the following options are incorrect?

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Important Questions on Rotational Dynamics

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A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic energy of the particle becomes equal to 8×10-4 J by the end of the second revolution after the beginning of the motion?
MEDIUM

One end of a rod of length L=1 m is fixed to a point on the circumference of a wheel of radius R=13 m. The other end is sliding freely along a straight channel passing through the center O of the wheel as shown in the figure below. The wheel is rotating with a constant angular velocity ω (in radian per second) about O.

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The speed of the sliding end P when θ=60° is

EASY
In a uniform circular motion r,V and ω stands for radius vector, linear velocity and angular velocity respectively. Then which of the following is true?
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A rod of length 50 cm is pivoted at one end. It is raised such that it makes an angle of 30o from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad s-1 ) will be g=10 ms-2

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MEDIUM
A uniform solid sphere of radius R and radius of gyration K about an axis passing through the centre of mass, is rolling without slipping. Then the fraction of total energy associated with its rotation will be
MEDIUM
A tube of length 50 cm is filled completely with an incompressible liquid of mass 250 g and closed at both ends. The tube is then rotated in horizontal plane about one of its ends with a uniform angular velocity xF rad s-1. If F be the force exerted by the liquid at the other end then the value of x will be _____ .
EASY
What is the value of tangential acceleration in U.C.M. ?
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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-1. How much work is needed to stop it?
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The angular speed of truck wheel is increased from 900 rpm to 2460 rpm in 26 seconds. The number of revolutions by the truck engine during this time is ______.

(Assuming the acceleration to be uniform).

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A solid disc of radius a and mass m rolls down without slipping on an inclined plane making an angle θ with the horizontal. The acceleration of the disc will be 2 bgsinθ, where b is _______.  (Round off to the nearest integer)

(g= acceleration due to gravity and θ= angle as shown in figure)

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EASY
A solid sphere of mass, m and radius, R is rotating about its diameter. A solid cylinder of the same mass and same radius is also rotating about its geometrical axis with an angular speed twice that of the sphere. The ratio of their kinetic energies of rotation EsphereEcylinder will be
MEDIUM
A uniform ring of radius R is moving on a horizontal surface with speed v, then climbs up a ramp of inclination 30° to a height h. There is no slipping in the entire motion. Then, h is
EASY
A solid sphere of mass 2 kg is rolling on a frictionless horizontal surface with velocity 6 m s-1. It collides on the free end of an ideal spring whose other end is fixed. The maximum compression produced in the spring will be (Force constant of the spring = 36 N m-1).
MEDIUM
A ball is spun with angular acceleration α=6t2-2t where t is in second and α is in rad s-2. At t=0, the ball has angular velocity of 10 rad s-1 and angular position of 4 rad. The most appropriate expression for the angular position of the ball is
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Two discs of same moment of inertia ( I )  are rotating in same sense about their regular axis passing through centre and perpendicular to the plane of disc with angular velocities ω1 and ω2. They are brought into contact face to face coinciding the axis of rotation. The expression for loss in energy during this process is
HARD
A uniformly thick wheel with moment of inertia I and radius R is free to rotate about its centre of mass (see fig). A massless string is wrapped over its rim and two blocks of masses m1 and m2m1>m2 are attached to the ends of the string. The system is released from rest. The angular speed of the wheel when m1 descends by a distance h is:

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MEDIUM
A stationary horizontal disc is free to rotate about its axis. When a torque is applied on it, its kinetic energy as a function of θ, where θ is the angle by which it has rotated, is given as kθ2. If its moment of inertia is I then the angular acceleration of the disc is:
HARD
A cylinder of mass, m is allowed to roll on a smooth horizontal table with a spring of spring constant, k attached to it so that it executes SHM about the equilibrium position. What is the time period, T of oscillations?
EASY
A rigid body is rotating with angular velocity ω about an axis of rotation. Let v be the linear velocity of particle which is at perpendicular distance r from the axis of rotation. Then the relation v=ωr implies that
MEDIUM

A ball is rolling without slipping in a spherical shallow bowl (radius R ) as shown in the figure and is executing simple harmonic motion. If the radius of the ball is doubled, then the time period of oscillation

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