The minimum fresh air requirement of a residential building is specified to be 0.35 air changes per hour (ASHRAE, Standard 62, 1989). That is, 35 percent of the entire air contained in a residence should be replaced by fresh outdoor air every hour. If the ventilation requirement of a 2.7-m-high, 200-m2 residence is to be met entirely by a fan, determine the flow capacity in L/min of the fan that needs to be installed (5-point). Also determine the minimum diameter of the duct if the average air velocity is not to exceed 5 m/s (5-point).

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

What is the chief metrological difference between measuring with a microscope and with an electronic comparator? a. the microscope is limited to small workpieces.a. the microscope is limited to small workpieces. c. the comparator can only examine one point on the workpiece. d. the microscope carries its own standard.