. A crude oil of viscosity 0.9 poise and sp. gr. 0.8 is flowing through a horizontal circular pipe of diameter 80 mm and of length 15 m. Calculate the difference of pressure at the two ends of the pipe, if 50 kg of the oil is collected in a tank in 15 seconds.

Fluid of specific gravity of 0.78 flows in a 127mm diameter pipe. Find the critical velocity in m/s. The absolute viscosity is 8.14x10^-2 Pa-s

6. A hydraulic lift (see below) of the type commonly used for greasing automobiles consists of a 280.00 mm diameter ram which slides in a 280.18 mm-diameter cylinder, the annular space being filled with oil film of thickness t = 0.09 mm, having a viscosity 0.3612 kg/(m s). If the rate of travel of the ram is v= 0.22 m/s, find the frictional resistance when 2 m of the ram is engaged in the cylinder. Take the weight of ram as 500 N. Ram Oil film -Fixed cylinder