a. In a conical vessel, the water level rises at a constant rate v₀. How does the rate of water entering a vessel through a tube of section s depend on time? At time zero, the vessel is empty.
b. A jet of oil hitting the surface of the water spreads over it in a round spot of thickness h. How does the speed of movement of the spot boundary depend on time, if the volume of oil q enters per unit of time? At the initial time, the spot radius is zero.
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