An aeroplane of mass $4.5 \times 10^4 \mathrm{~kg}$ and total wing area of $600 \mathrm{~m}^2$ is travelling at a constant height. The pressure difference between the upper and lower surfaces of its wings is (Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )

In a hydraulic lift, if the radius of the smaller piston is 5 cm and the radius of the larger piston is 50 cm , then the weight that the larger piston can support when a force of 250 N is applied to the smaller piston is

A liquid drop of diameter $D$ splits into 3375 small identical drops. If $S$ is the surface tension of the liquid, then the change in the surface energy in the process is

If water flows with a velocity of $20 \mathrm{cms}^{-1}$ in a pipe of radius 2 cm , then the flow is (The coefficient of viscosity of water is $10^{-3} \mathrm{~kg} \mathrm{~m}^{-1} \mathrm{~s}^{-1}$ and density of water is $10^3 \mathrm{~kg} \mathrm{~m}^{-3}$ )