In the process of producing engine valves, the valves are subjected to a first grind. Valves
whose thicknesses are within the specification
are ready for installation. Those valves whose
thicknesses are above the specification are
reground, while those whose thicknesses are
below the specification are scrapped. Assume
that after the first grind, 74% of the valves meet
the specification, 15% are reground, and 11% are
scrapped. Furthermore, assume that of those
valves that are reground, 90% meet the
specification, and 10% are scrapped.
Find the probability that a valve is ground only once. Round
the answer to two decimal places.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Calculate the bore of a cylinder that has a stroke of 18 inches and an extension time of 6 seconds at a flow rate of 4 gal/min.

The characteristic roots of a dynamic system are: 1.7920 1.8160 i, -1.7920 1.8160 i, -0.4160 what is the order of this system? what are the settling time and damping ratio of the system?