What is the pressure inside an alveolus having a radius of 2.50 X 10 m if the surface tension of the fluidlined wall is the same as for soapy water? You may assume the pressure is the same as that created by a spherical bubble.

On another planet that you are exploring, a large tank is open to the atmosphere and contains ethanol. A horizontal pipe of cross-sectional area 7.0×10−4m27.0×10−4m2 has one end inserted into the tank just above the bottom of the tank. The other end of the pipe is open to the atmosphere. The viscosity of the ethanol can be neglected. You measure the volume flow rate of the ethanol from the tank as a function of the depth hh of the ethanol in the tank. If you graph the volume flow rate squared as a function of hh, your data lie close to a straight line that has slope 2.09×10−5m5/s22.09×10−5m5/s2.   What is the value of gg, the acceleration of a free-falling object at the surface of the planet? Express your answer with the appropriate units.

it’s a lovely day and you decide to launch a giant helium balloon. Once filled, your balloon is a perfect sphere with a radius of 6.90 m. You consider having the balloon lift a crate of water balloons. What is the maximum weight the filled helium balloon can just lift (solve for the equilibrium condition where upward force equals downward force)? Assume that the membrane of the helium balloon has a mass of 920 kg (this does not include the mass of the helium within nor the mass of the crate). Neglect the buoyant force on the crate of water balloons. Density of He is 0.179 kg/m3. Density of air is 1.29 kg/m3. Volume of a sphere is 4/3 π r3. Weight is in N (not kg)

At a given instant, the blood pressure in the heart is 1.4 x 10^4 Pa. If an artery in the brain is 0.49m above the heart, what is the pressure in the artery? Ignore any pressure changes due to blood flow.