Outdoor air enters an ac unit at 10℃ and 35 % relative humidity at a steady rate of 17 m3⁄ and it leaves at 25℃ and 65 % relative humidity. the outdoor air is first heated to 22℃ in the heating section and then humidified by the injection of hot steam in the humidifying section. assuming the entire process takes place at a pressure of 1 , determine (a) the rate of heat supply in the heating section and (b) the mass flow rate of steam required in the humidifying section.

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.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.