water flows through a 4.0-cm-diameter horizontal pipe at a speed of 1.3 m/s. the pipe then narrows down to a diameter of 2.0 cm. part a ignoring viscosity, what is the pressure difference between the wide and narrow sections of the pipe? ignoring viscosity, what is the pressure difference between the wide and narrow sections of the pipe? 850 pa 3400 pa 9300 pa 12700 pa 13500 pa