A drawing operation is to be performed on a perfectly plastic material with strength coefficient- 100 MPa and strain hardening exponent-0. Neglect redundant strain. Die/work material friction coefficient=0 a)-What is the drawing stress? If this stress is a function of the area reduction, state so. b)-What is the strength of the material after drawing? If this strength is a function of the area 4. reduction, state so. c)-What is the maximum area reduction possible?

On a average work day more than work place firs are reorted

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?

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