In a simple concentric shaft-bearing arrangement, the lubricant flows in the $$2$$ $$mm$$ gap between the shaft and the bearing. The flow may be assumed to be a plane Couette flow with zero pressure gradient. The diameter of the shaft is $$100$$ $$mm$$ and its tangential speed is $$10$$ $$m/s.$$ The dynamic viscosity of the lubricant is $$0.1$$ $$kg/m.s.$$ The frictional resisting force (in newton) per $$100$$ $$mm$$ length of the bearing is ______________.

For a completely submerged body with center of gravity $$'G'$$ and center of buoyancy $$'B',$$ the condition of stability will be

Consider one dimensional steady state heat conduction across a wall (as shown in figure below) of thickness $$30$$ $$mm$$ and thermal conductivity $$15$$ $$W/m.K.$$ At $$x=0,$$ a constant heat flux, $$q'' = 1 \times {10^5}\,\,W/{m^2}$$ is applied. On the other side of the wall, heat is removed from the wall by convection with a fluid at $${25^ \circ }C$$ and heat transfer coefficient of $$250W/{m^2}.K.$$ The temperature (in $${}^ \circ C$$), at $$x=0$$ is ___________

The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by $${{{T_w} - T} \over {{T_w} - {T_\infty }}} = a + b{y \over L} + c{\left( {{y \over L}} \right)^2},$$ where $$y$$ is measured perpendicular to the plate, $$L$$ is the length, and $$a,b$$ and $$c$$ are arbitrary constants. $${{T_w}}$$ and $${{T_\infty }}$$ are wall and ambiyent temperatures, respectively. If the thermal conductivity of the fluid is $$k$$ and the wall heat flux is $$q'',$$ the Nusselt number $$\,{N_u} = {{q''} \over {{T_w} - {T_\infty }}}{L \over k}$$ is equal to