System of Particles and Rotational Motion

Two circular discs of radius each 10 cm are joined at their centres by a rod of length 30 cm and mass 600 gm as shown in figure. If the mass of each disc is 600 gm and applied torque between two discs is 43 105 dyne.cm, the angular acceleration of the discs about the given axis AB is rad/s2. [figure]

1. 100
2. 22
3. 27
4. 11

The moment of inertia of a square loop made of four uniform solid cylinders, each having radius R and length L (R < L) about an axis passing through the mid points of opposite sides, is (Take the mass of the entire loop as M):

1. 34MR2 + 16ML2
2. 38MR2 + 712ML2
3. 34MR2 + 712ML2
4. 38MR2 + 16ML2

A solid sphere of mass 5 kg and radius 10 cm is kept in contact with another solid sphere of mass 10 kg and radius 20 cm. The moment of inertia of this pair of spheres about the tangent passing through the point of contact is kg m2.

1. 0.18
2. 0.72
3. 0.36
4. 0.63

The moment of inertia of a circular ring of mass M and diameter r about a tangential axis lying in the plane of the ring is :

1. 38Mr2
2. 2Mr2
3. 12Mr2
4. 32Mr2