Water is flowing over an inclined overflow dam. The thickness of the water film is small compared to its width. One can perform a shell balance for the fully developed flow regime of the falling film of water and get an expression for the flow rate as a function of the thickness and the slope. In the above problem, the water is flowing in a slit-like tunnel, and the water fills half the slit. Can you repeat the shell balance without assuming that air offers negligible resistance at the surface to the The flow of water. Please note that when you consider the flow of air you need not consider gravity. But for the flow of water of course gravitational force needs to be considered