A nylon thread is subjected to a 2-lb tension force. Knowing that E = 0.5 × 106 psi and that the maximum allowable normal stress is 6 ksi, determine (a) the required diameter of the thread, (b) the corresponding percent increase in the length of the thread.

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?

Wiy doeres rere okhn a pump whon working betwon the same pressure range?

In general, how do thermosetting plastics compare to thermoplastics in mechanical and physical properties?