Acomputer cooled by a fan contains eight pcbs, each dissipating 9w power. the height of the pcbs is 11 cm and the length is 18.8 cm. the cooling air is supplied by a 20 w fan mounted at the inlet. if the temperature rise of air as it flows through the case of the computer is not to exceed 9 c, determine (a) the flow rate of the air that the fan needs to deliver and (b) the fraction of the temperature rise of air that is due to the heat generated by the fan and its motor.

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

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.

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