Oxygen is supplied isothermally to an astronaut through an umbilical hose that is 7 m long. The pressure in the oxygen tank is 200 kPa at a temperature of 10 ºC, and the pressure in the space suit is 20 kPa. If the umbilical hose has an equivalent roughness of 0.01 mm, what should the hose diameter be to supply oxygen at a rate of 0.05 kg/s? (The viscosity of O2 is 2.0 × 10-5 Pa s) [25 marks]