a$)$ Inside a $60-$mm diameter cylinder a piston of $59$ mm diameter rotates concentrically. Both the cylinder

and piston are $80$ mm long. If the space between the cylinder and piston is filled with oil of viscosity

of $0\mathrm{.}3N\frac{s}{m^2}$ and a torque of $1\mathrm{.}5$ Nm is applied, find the rpm of the piston and the power required

$($Refer Fig $1).$

$(5$ Marks$)$