Falling water

Jayse_83

Hi,
Please could someone explain why it is that the cross section of water emerging from a tap decreases with tap distance ... is it due to air resistance acting to form some kind of aerodynamic shape? any thoughts would be much appreciated!

Doc Al

It's simply that the water accelerates as it falls. The rate (mass per second) at which water flows remains the same throughout the stream, but since the speed increases as it falls, the cross-section must decrease. The stream retains a narrow shape (instead of falling straight down like rain) due to surface tension holding things together.

Jayse_83

wow! great answer, thanks Doc :D

Danger

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