A horizontal pipe, of diameter D, contains water flowing at speed v1. At one point, the pipe narrows to half the diameter. a) Find the difference in pressure between the two parts of the pipe.

b) A manometer (consisting of a U-tube containing

mercury) is connected to the pipe as shown. Find h, the difference in height between the mercury columns in the U-tube, in terms of v1.

c) Check your answers by using dimensional analysis.