A centrifugal compressor rotating at 35,000 rpm is tested in the open atmosphere of 14.7 psia and 60° F. The mass flow rate of 1.4 lb _m /s, discharge stagnation pressure of 45 psia, and temperature of 280°F are measured. If the mechanical efficiency associated with the bearing and seal friction losses is estimated to be 95% (but leakage is neglected, determine the overall compressor efficiency and the brake horsepower. Also determine the expected discharge pressure and brake horsepower if the rotating speed is reduced to 30,000 rpm.