Polycarbonate, PC, is used for aircraft canopies. A batch of this polymer was found to fail prematurely when impacted by a 4 pound bird during qualification studies. You suspect that the problem is due to a molecular weight difference for this particular batch of polymer compared to previous batches. You decide to perform dilute solution viscosity studies to determine the Mol. wt. Assume density is 1.2 g/cm3 What solvent would you use? Justify your answer

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.

The higher the astm grain size number, the finer the gran is. a)-true b)-false

Aturning operation is performed with following conditions: rake angle of 12°, a feed of 0.35 mm/rev, and a depth of cut of 1.1 mm. the work piece is aluminum alloy 6061 with t6 heat treatment (a16061-t6). the resultant chip thickness was measured to be 1.0 mm. estimate the cutting force, fc. use shear stress of 207 mpa and coefficient of friction on the tool face of 0.6.