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General
Easy
Question
A disc of radius r is rotating about its centre with an angular speed 
. It is gently placed on a rough horizontal surface. After what time it will be in pure rolling ?
The correct answer is:
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Portion AB of the wedge shown in figure is rough and BC is smooth. A solid cylinder rolls without slipping from A to B. The ratio of translational kinetic energy to rotational kinetic energy, when the cylinder reaches point C is :
Portion AB of the wedge shown in figure is rough and BC is smooth. A solid cylinder rolls without slipping from A to B. The ratio of translational kinetic energy to rotational kinetic energy, when the cylinder reaches point C is :
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Inner and outer radii of a spool are r and R respectively. A thread is wound over its inner surface and placed over a rough horizontal surface. Thread is pulled by a force F as shown in fig. then in case of pure rolling
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A hinged construction consists of three rhombs with the ratio of sides 5:3:2. Vertex A3 moves in the horizontal direction at a velocity v. Velocity of A2 is
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A particle starts from the point (0m, 8m) and moves with uniform velocity of 
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A uniform rod is fixed to a rotating turntable so that its lower end is on the axis of the turntable and it makes an angle of 20° to the vertical. (The rod is thus rotating with uniform angular velocity about a vertical axis passing through one end.) If the turntable is rotating clockwise as seen from above.
Is there a torque acting on it, and if so in what direction?
A uniform rod is fixed to a rotating turntable so that its lower end is on the axis of the turntable and it makes an angle of 20° to the vertical. (The rod is thus rotating with uniform angular velocity about a vertical axis passing through one end.) If the turntable is rotating clockwise as seen from above.
Is there a torque acting on it, and if so in what direction?
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A uniform rod is fixed to a rotating turntable so that its lower end is on the axis of the turntable and it makes an angle of 20° to the vertical. (The rod is thus rotating with uniform angular velocity about a vertical axis passing through one end.) If the turntable is rotating clockwise as seen from above.
What is the direction of the rod's angular momentum vector (calculated about its lower end)?
A uniform rod is fixed to a rotating turntable so that its lower end is on the axis of the turntable and it makes an angle of 20° to the vertical. (The rod is thus rotating with uniform angular velocity about a vertical axis passing through one end.) If the turntable is rotating clockwise as seen from above.
What is the direction of the rod's angular momentum vector (calculated about its lower end)?
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A child with mass m is standing at the edge of a disc with moment of inertia I, radius R, and initial angular velocity 
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A child with mass m is standing at the edge of a disc with moment of inertia I, radius R, and initial angular velocity . See figure given below. The child jumps off the edge of the disc with tangential velocity v with respect to the ground. The new angular velocity of the disc is
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A man is sitting in a smooth groove on a horizontal circular table at the edge by holding a rope joined to the centre. The moment of inertia of table is I. Mass of man = M. Man now pulls the rope so that he comes to the centre. The angular velocity of the table :
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A small bead of mass m moving with velocity v gets threaded on a stationary semicircular ring of mass m and radius R kept on a horizontal table. The ring can freely rotate about its centre. The bead comes to rest relative to the ring. What will be the final angular velocity of the system?
A small bead of mass m moving with velocity v gets threaded on a stationary semicircular ring of mass m and radius R kept on a horizontal table. The ring can freely rotate about its centre. The bead comes to rest relative to the ring. What will be the final angular velocity of the system?
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A block of mass m is attached to a pulley disc of equal mass m, radius r by means of a slack string as shown. The pulley is hinged about its centre on a horizontal table and the block is projected with an initial velocity of 5 m/s. Its velocity when the string becomes taut will be
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A solid cone hangs from a frictionless pivot at the origin O, as shown. If 
and
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A solid cone hangs from a frictionless pivot at the origin O, as shown. If and are unit vectors, and a, b, and c are positive constants, which of the following forces F applied to the rim of the cone at a point P results in a torque t on the cone with a negative component t Z ?
Physics-General
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A sphere is placed rotating with its centre initially at rest in a corner as shown in figure (A) & (B). Coefficient of friction between all surfaces and the sphere is 
. Find the ratio of the frictional force 
by ground in situations (A) & (B).
A sphere is placed rotating with its centre initially at rest in a corner as shown in figure (A) & (B). Coefficient of friction between all surfaces and the sphere is . Find the ratio of the frictional force by ground in situations (A) & (B).
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For the pivoted slender rod of length l as shown in figure, the angular velocity as the bar reaches the vertical position after being released in the horizontal position is
For the pivoted slender rod of length l as shown in figure, the angular velocity as the bar reaches the vertical position after being released in the horizontal position is
Physics-General
