A fully loaded boeing aircraft has a mass of $5.4\times {10}^5 \mathrm{kg}$. Its total wing area is $500 {\mathrm{m}}^2$. It is in level flight with a speed of $1080 \mathrm{km} {\mathrm{h}}^{-1}$. If the density of air $\rho$ is $1.2 \mathrm{kg} {\mathrm{m}}^{–3}$, the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface in percentage will be

($g=10 \mathrm{m} {\mathrm{s}}^{-2}$)

A metal block of base area $0.20 {\mathrm{m}}^2$ is placed on a table, as shown in figure. A liquid film of thickness $0.25 \mathrm{mm}$ is inserted between the block and the table. The block is pushed by a horizontal force of $0.1 \mathrm{N}$ and moves with a constant speed. If the viscosity of the liquid is $5.0\times {10}^{–3} \mathrm{Pl}$, the speed of block is ______ $\times {10}^{-3} \mathrm{m} {\mathrm{s}}^{-1}$.

If $1000$ droplets of water of surface tension $0.07 \mathrm{N} {\mathrm{m}}^{-1}$. having same radius $1 \mathrm{mm}$ each, combine to from a single drop. In the process the released surface energy is-

$\left(\text{Take} \mathrm{\pi }=\frac{22}{7}\right)$