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IMPORTANT
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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 , where is the angle by which it has rotated, is given as . If its moment of inertia is then the angular acceleration of the disc is:
(a)
(b)
(c)
(d)

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Important Questions on Rotational Motion
MEDIUM
JEE Main
IMPORTANT
A ball is thrown vertically up (taken as ) from the ground. The correct momentum-height diagram is:

MEDIUM
JEE Main
IMPORTANT
The following bodies are made to roll up (without slipping) the same inclined plane from a horizontal plane: (i) a ring of radius (ii) a solid cylinder of radius and (iii) a solid sphere of radius If, in each case, the speed of the center of mass at the bottom of the incline is same, the ratio of the maximum heights they climb is:

MEDIUM
JEE Main
IMPORTANT
A thin smooth rod of length and mass is rotating freely with angular speed about an axis perpendicular to the rod and passing through center. Two beads of mass and negligible size are at the center of the rod initially. The beads of mass and negligible size are at the center of the rod initially. The beads are free to slide along the rod. The angular speed of the system, when the beads reach the opposite ends of the rod, will be:

MEDIUM
JEE Main
IMPORTANT
A wedge of mass lies on a frictionless plane. A particle of mass approaches the wedge with speed There is no friction between the particle and the plane or between the particle and the wedge. The maximum height climbed by the particle on the wedge is given by:

MEDIUM
JEE Main
IMPORTANT
Moment of inertia of a body about a given axis is Initially the body is at rest. In order to produce a rotational kinetic energy of the angular acceleration of must be applied about the axis for a duration of:

HARD
JEE Main
IMPORTANT
An -shaped object, made of thin rods of uniform mass density, is suspended with a string as shown in figure. If and the angle made by with downward vertical is then:


MEDIUM
JEE Main
IMPORTANT
A rod of length is pivoted at one end. It is raised such that it makes an angle of from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in ) will be

HARD
JEE Main
IMPORTANT
A thin circular plate of mass and radius has its density varying as with as constant and is the distance from its centre. The moment of Inertia of the circular plate about an axis perpendicular to the plate and passing through its edge is . The value of the coefficient is:
