$A$ flywheel is an important part of a steam engine because it

$A$ flat surface of a thin uniform disk $A$ of radius $R$ is glued to a horizontal table. Another thin uniform disk $B$ of mass $M$ and with the same radius $R$ rolls without slipping on the circumference of $A$,as shown in the figure. $A$ flat surface of $B$ also lies on the plane of the table. The center of mass of $B$ has a fixed angular speed $\omega$ about the vertical axis passing through the center of $A$. The angular momentum of $B$ is $n M \omega R^2$ with respect to the center of $A$. Which of the following is the value of $n$?

$A$ ring of mass $M$ and radius $R$ sliding with a velocity $v_0$ suddenly enters a rough surface where the coefficient of friction is $\mu$,as shown in the figure. Choose the correct alternative$(s)$.

$A$ uniform metallic rod rotates about its perpendicular bisector with constant angular speed. If it is heated uniformly to raise its temperature slightly,what happens to its speed of rotation?

Disc $A$ and disc $B$ (with a hole) have equal mass and radius,and a string is wrapped around them as shown. An equal force $F$ is applied to the string of each body. Friction is sufficient for rolling. After time $t$,the velocity of $A$ is $v_A$ and that of $B$ is $v_B$,and their kinetic energies are $k_A$ and $k_B$ respectively. Then:

The angular momentum of a rotating body is $L$. When the frequency of the rotating body is tripled and its kinetic energy is made one-third,the new angular momentum becomes: