Hello, "Potential Energy (PE) + Kinetic Energy (KE) = Total Energy When air travels through an airway at a CONSTANT FLOW RATE, the total energy of the fluid (PE + KE) decreases because friction converts some of this energy into heat. Since the fluid is moving at a constant flow rate, the loss is in potential energy (decrease in hydrostatic pressure)." I don't understand this. Shouldn't the moving object lose K.E. Shouldn't resistance decrease speed.