What should be the difference in pressure across the ends of a4 km long horizontal pipe line of diameter 8 cm to make water flow at the rate 20 litre/seta_("water")=10^(-2)MKS.Neglect all forces other than viscous force. [Hint : V=(piPr^(4))/(8hl)]

What should be the difference in pressure across the ends of a4 km lon

1.	What should be the difference in pressure across the ends of a4 km long horizontal pipe line of diameter 8 cm to make water flow at the rate 20 litre/seta_("water")=10^(-2)MKS.Neglect all forces other than viscous force. [Hint : V=(piPr^(4))/(8hl)]
Answer» Solution :`R=(d)/(2)=(8)/(2)=4cm=4XX10^(-2)m` `L=4km=4xx10^(3)m` `V=20(L)/(S)=20xx10^(-3)m^(3)//s` `eta=10^(-2)MKS,P=?` `V=(piPr^(4))/(8etal)` `P=(8etalV)/(pir^(4))` `P=(8XX10^(-2)xx4xx10^(3)xx20xx10^(-3))/(3.14xx(4xx10^(-2))^(4))=(50xx10^(5))/(6.28)` `thereforeP=7.96xx10^(5)Pa`