Water (ρ = 1000 kg m^-3) speeds up from 3 m/s to 5 m/s along a horizontal pipe. The pressure drop is:

Since the same volume of fluid must pass every cross-section per second (continuity), the fluid speeds up where the pipe narrows; Bernoulli's equation then says this faster-moving fluid has lower pressure - the principle behind a venturi meter and an aircraft wing's lift.