Afan was in use at a site where the usual atmospheric pressure and temperature were 101,3 kpa and 15°c, respectively. it was delivering 20 m3/s of air against a total pressure of 1520 pa and it absorbed 40 kw. it was belt driven at 1250 r/min. the fan was subsequently moved to a site where the atmospheric pressure and temperature are 80 kpa and 30°c, respectively. if the motor is now direct-coupled to the fan and drives it at 1460 r/min, calculate : a)- the flow rate. b)- the power required. c)- the fan efficiency. given : gas constant for air rair = 287 j/kg. k