Consider steady heat transfer between two large parallel plates at constant temperatures of T1 290 K and T2 150 K that are L 2 cm apart. Assuming the surfaces to be black (emissivity 1), determine the rate of heat transfer between the plates per unit surface area assuming the gap between the plates is: (a) filled with atmospheric air,
(b) evacuated,
(c) filled with fiberglass insulation, and
(d) filled with superinsulation h

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.

Wiy doeres rere okhn a pump whon working betwon the same pressure range?

The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false