A 1.75-cm diameter naphthalene mothball is suspended in an air stream at 280 K, 1.0 atm, and constant velocity of 1.4 m/s. Solid naphthalene exerts a vapor pressure of 2.8 Pa at 280 K. Consequently, the naphthalene very slowly sublimes into the passing air stream, with the rate limited by convective mass transfer. The density of solid naphthalene is 1.14 g/cm3, and the molecular weight is 128 g/mole. How long will it take for the mothball to shrink to half of its original diameter? Remember: as the mothball shrinks, its diameter is decreasing, which in turn affects the Reynolds and Sherwood numbers.

What precautions should you take to prevent injuries when dealing with heavy loads?

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.

Burgers vector is generally parallel to the dislocation line. a)-true b)-false