Diameter and length of pipe is given as 300 mm and 3200 m respectively which is used to flow 50 kg/s oil. Cross section at the point A is 40 m higher than point B. By using Hagen Poiseuille equation, determine the difference of pressure between 2 cross sections.

( ρ = 950 kg/m3 and ν = 2.1 ´ 10-4 m2/s)