An incompressible fluid (kinematic viscosity $$ = 7.4 \times {10^{ - 7}}\,\,{m^2}/s,$$ specific gravity, $$0.88$$) is held between two parallel plates. If the top plate is moved with a velocity of $$0.5$$ $$m/s$$ while the bottom one is held stationary, the fluid attains a linear velocity profile in the gap of $$0.5$$ $$mm$$ between these plates; the shear stress in Pascal on the surface of bottom plate is :

A fluid flow is represented by the velocity field $$\overrightarrow V = ax\,\overrightarrow i + ay\,\overrightarrow j ,$$ where a constant . The equation of stream line passing through a point $$(1, 2)$$ is

A closed cylinder having a radius $$R$$ and height $$H$$ is filled with oil of density $$\rho .$$ If the cylinder is rotated about its axis at an angular velocity of $$\omega $$ , then thrust at the bottom of the cylinder is

In a condenser, water enters at $${30^ \circ }C$$ and flows at the rate $$1500$$ $$Kg/hr.$$ The condensing steam is at a temperature of $${120^ \circ }C$$ and cooling water leaves the condenser at $${80^ \circ }C$$. Specific heat of water is $$4.187 kJ/kg$$ $$K.$$ If the overall heat transfer coefficient is $$2000$$ $$W/{m^2}K,$$ the heat transfer area is