2. Describe the three phases of the life cycle curve Draw the curve and label it in detail (the
axes, phases, type of product failure, etc)

3. Determine the failure rate for the following You have tested circuit boards for failures
during a 500-hour continuous use test Four of the 25 board s failed The first board failed
in 80 hours, the second failed in 150 hours, the third failed in 350 hours the fourth in
465 hours The other boards completed the 500 hour test satisfactorily What is the mean
life of the product?

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

Determine the damped natural frequencies and the steady state response of a decoupled damped forced two degrees of freedom system. 10ä1 + 2q1 20q1 10 cos t; 10q2 +4q2 + 40q2 10 cos t

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.