$A$ particle moves in a circular path with decreasing speed. Choose the correct statement.

$A$ small mass $m$ is attached to a massless string whose other end is fixed at $P$ as shown in the figure. The mass is undergoing circular motion in the $x-y$ plane with centre at $O$ and constant angular speed $\omega$. If the angular momentum of the system,calculated about $O$ and $P$ are denoted by $\vec{L}_O$ and $\vec{L}_P$ respectively,then

$A$ solid cylinder of mass $20 \ kg$ rotates about its axis with an angular speed of $100 \ rad \cdot s^{-1}$. The radius of the cylinder is $0.25 \ m$. The magnitude of its angular momentum about the axis of the cylinder is ........ $J \cdot s$.

$A$ particle moves along a circular path with decreasing speed. Hence,

$A$ particle of mass $m$ is moving with constant velocity $v$ parallel to the $x$-axis as shown in the figure. Its angular momentum about origin $O$ is ..........

$A$ body of mass $2 \ kg$ is moving in a circular path of radius $2 \ m$ with uniform speed. If the centripetal force acting on it is $100 \ N$,then its angular momentum is ....... $J \cdot s$.