An airship is o operate at 20 m/s in air at staanclard conditions. a model is constructed to2scale and tested in a wind tunnel at the same air temperature to determine drag. what criterion should be considered to obtain dynamic similarity? lf the moel is sicd at ts n/s, what pres should be used in the wind tunnel? if the model drag force is 250 n, what will be the drag of the prototype?

On a average work day more than work place firs are reorted

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.

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false