The dancer on ice spins faster when she folds her arms. This is due to

The moment of inertia of a ring is $0.4 kg m^2$. If it is rotating at a rate of $2100$ revolutions per minute, calculate the torque required to stop it in $2.0$ seconds. What will be the work done?

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 :

A small particle of mass m is projected at an angle $\theta$ with the x-axis with an initial velocity ${\mathrm{v}}_0$ in the x-y plane as shown in the figure. At a time$\mathrm{t}<\frac{{\mathrm{v}}_0\mathrm{sin\theta }}{\mathrm{g}}$​, the angular momentum of the particle is