If a person sitting on a rotating stool with his hands outstretched, suddenly pulls his arms inside then his:

Two solid cylinders $\mathrm{P}$ and $\mathrm{Q}$  of same mass and same radius start rolling down a fixed inclined plane from the same height at the same time. Cylinder $\mathrm{P}$ has most of its mass concentrated near its surface, while $\mathrm{Q}$ has most its mass concentrated near the axis.

A boy is standing on a rotating table with dumbbells in his hand. He suddenly pulls the dumbbells towards his chest, the angular velocity of the table will:

A child is standing with folded hands at the centre of a platform rotating about its central axis. The kinetic energy of the system is $\mathrm{K}$. The child now stretches his arms so that moment of inertia of the system doubles. The kinetic energy of the system now is:

A thin circular ring of mass M and radius $\mathrm{r}$ is rotating about its axis with a constant angular velocity $\omega$. Two objects, each of mass $\mathrm{m}$, are attached gently to the opposite ends of the diameter of the ring. The wheel now rotates with an angular velocity

A thin ring of mass $2\mathrm{kg} , \mathrm{radius} 0.5 \mathrm{m}$ is rolling without slipping on a horizontal plane with velocity $1\mathrm{m}/\mathrm{s}$. A small ball of mass $0.1\mathrm{kg}$ , moving with velocity $20 \mathrm{m}/\mathrm{s}$ in the opposite direction, hits the ring at a height of $0.75 \mathrm{m}$ and goes vertically up with velocity $10 \mathrm{m}/\mathrm{s}$  immediately after the collision, choose the correct statement :