$A$ solid sphere,a solid cylinder,a disc,and a ring are rolling down an inclined plane. Which of these bodies will reach the bottom simultaneously?

Two solid cylinders $P$ and $Q$ of same mass and same radius start rolling down a fixed inclined plane from the same height at the same time. Cylinder $P$ has most of its mass concentrated near its surface,while $Q$ has most of its mass concentrated near the axis. Which statement$(s)$ is (are) correct?

$A$ cylinder rolls up an inclined plane to a certain height and then rolls down. (It does not slip during the entire motion.) What is the direction of the frictional force acting on the cylinder?

$A$ solid sphere is thrown up a rough incline. The sphere rolls up without slipping and eventually comes down rolling without slipping. The direction of rolling friction in upward and downward motion respectively is ............

Starting from rest,at the same time,a ring,a coin (disc),and a solid ball of the same mass roll down an incline without slipping. The ratio of their translational kinetic energies at the bottom will be:

$A$ solid sphere and a thin uniform circular disc of same radius are rolling down an inclined plane without slipping. If the acceleration of the sphere is $3 \,ms^{-2}$, then the acceleration of the disc is (in $\,ms^{-2}$)