Consider a situation where water is used as the coolant in a heat exchanger for a micro-electromechanical device (MEM device). The characteristic velocity is estimated to be 10 microns/s, the length scale of the system is 100 microns, and the characteristic temperature difference of the problem is 10 K. Given what you know about the system, what assumptions can you make about the flow (namely: is it viscous (diffusion)dominated or inertia (convection) dominated, is it conduction dominated or convection dominated, are viscous dissipation effects important, etc.)

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

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented