A cylinder of mass $15 \mathrm{kg}$ and radius $R$ is to be raised onto a horizontal step of height $h=\frac{R}{5}$ as shown in figure. A rope is wrapped around the cylinder and pulled horizontally with force $F.$ Assuming the cylinder docs not slip on the step, find the minimum force $F$ (in $N$) necessary to raise the cylinder.

A uniform rod of mass $m=2\sqrt{10} \mathrm{kg}$ and length $l$ can rotate in vertical plane about a smooth horizontal axis hinged at point $H.$ Find angular acceleration $a$ of the rod just after it is released from initial position making an angle of $37°$ with horizontal from rest? Find force (in $N$) exerted by the hinge just after the rod is released from rest.