A fan is to be selected to ventilate a bathroom whose dimensions are 2 m × 3 m × 3 m. The air velocity is not to
exceed 7 m/s to minimize vibration and noise. The combined
efficiency of the fan–motor unit to be used can be taken to
be 50 percent. If the fan is to replace the entire volume of air
in 15 min, determine (a) the wattage of the fan–motor unit to
be purchased, (b) the diameter of the fan casing, and (c) the
pressure difference across the fan. Take the air density to be
1.25 kg/m3
and disregard the effect of the kinetic energy correction factors.

Atmospheric air has a temperature (dry bulb) of 80° f and a wet bulb temperature of 60° f when the barometric pressure is 14.696 psia. determine the specific humidity, grains/lb dry air. a. 11.4 c. 55.8 d. 22.5 b. 44.1

The process in which the system pressure remain constant is called a)-isobaric b)-isochoric c)-isolated d)-isothermal

Tom is having a problem with his washing machine. he notices that the machine vibrates violently at a frequency of 1500 rpm due to an unknown rotating unbalance. the machine is mounted on 4 springs each having a stiffness of 10 kn/m. tom wishes to add an undamped vibration absorber attached by a spring under the machine the machine working frequency ranges between 800 rpm to 2000 rpm and its total mass while loaded is assumed to be 80 kg. a) what should be the mass of the absorber added to the machine so that the natural frequency falls outside the working range? b) after a first trial of an absorber using a mass of 35 kg, the amplitude of the oscillation was found to be 10 cm. what is the value of the rotating unbalance? c) using me-3.5 kg. m, find the optimal absorber (by minimizing its mass). what would be the amplitude of the oscillation of the absorber?