Question

Water is conveyed through a tube 8 cm in diameter and 4 km in length at the rate of 120 litres per minute. Calcualte the pressure difference required to maintain the flow. Coefficient of viscosity of water = 0.001 SI units.
[Hint" "V=(piPr^(4))/(8etal)]

Answer 1

Answer:

Volume of the tube = pi r^2 L = pi * 4/100 * 4/100 * 4000 m^3

Volume of water flown per second = 20 ltr = 20 * 10^-3 m^3 /s

So time of flow = pi * 4/100 * 4/100 * 4000 / 20 * 10^-3

==> 320 pi second

So velocity of rush = 4000 / 320 pi = 25/2pi m/s

Hence kinetic energy of liquid going out 1/2 * ρ * V * v^2

Force = Pressure * area

Work performed to push water through length of tube = Pressure * area * length = pressure * volume = P * V

By the conservation of energy P V = 1/2 * ρ * V * v^2

Cancelling and plugging v you can get P = 125 * 625 / pi^2 Pa

hope it helps...

Answer 2

Answer:

i think 5 atm i hope helpef u