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A uniform disc of mass M and radius R is released from rest in the shown position. PQ is a string, OP is a horizontal line, O is the centre of the disc and distance OP is R2. Then tension in the string just after the disc is released will be:

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Important Questions on Rotational Motion

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A cord is wound over a cylinder of radius r and moment of inertia I. A mass m is attached to the free end of the cord. The cylinder is free to rotate about its own horizontal axis. If mass m is released from rest, then the velocity of the mass after it had fallen through a distance h, will be
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A uniform square plate of mass m is supported, as shown. If the cable suddenly breaks, then the angular acceleration of the plate is

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A uniform circular disc A of radius r is made from a metal plate of thickness t and another uniform circular disc B of radius 4r is made from the same metal plate of thickness t/4. If equal torques act on the discs A and B, initially both being at rest. At a later instant, the angular speeds of a point on the rim of A and another point on the rim of B are ωA and ωB respectively. We have 
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Figure shows a uniform disc, with mass M=2.4 kg and radius R=20 cm, mounted on a fixed horizontal axle. A block of mass m=1.2 kg hangs from a massless cord that is wrapped around the rim of the disc. The tension in the cord is

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A uniform ladder of length 5 m is placed against the wall in vertical plane as shown in the figure. If coefficient of friction μ is the same for both the wall and the floor then minimum value of μ for it not to slip is 

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Physics
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A uniform rod of length 4L and mass M is suspended from a horizontal roof by two light strings of length L and 2L as shown. Then the tension in the left string of length L is

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A rod of mass m is supported by string AB and friction due to the wall. Then friction force on rod due to the wall is: (g=acceleration due to gravity)

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A rope is wound around a hollow cylinder of mass 3 kg and radius 40 cm. What is the angular acceleration of the cylinder if the rope is pulled with a force of 30 N?