Pipelines are cleaned by pushing through them a close-fitting cylinder called a pig. the name comes from the squealing noise it makes sliding along. suppose the pig diameter is 0.149 m and its length 0.6 m. it cleans a 0.15-m-diameter pipe at a speed of 1.2 m/s. if the clearance is filled with glycerin at 20°c, what pressure difference, in pascals, is needed to drive the pig? assume a linear velocity profile in the oil and neglect air drag,