Hello everyone,

 

Quick question. When there is a pipe and you constrict it there is higher pressure loss. Is this pressure lost permanent? What is this pressure loss, is it loss as heat, are liquid molecules converted to heat, are they lost? What happens to liquid molecules if the hydrostatic pressure drops to zero do they stop or do they still move because of the kinetic energy? Thanks!!

Molecules are not converted to heat; heat is a flow of energy, so it comes from some other energy source or as waste from work being done. Molecules are also not lost; in this kind of problem mass is a conserved quantity.

Thanks!!