Around steel bar having sy = 800 mpa is subjected to loads producing calculated stresses of p∕a = 70 mpa, tc∕j = 200 mpa, mc∕i = 300 mpa, and 4v∕3a = 170 mpa. (a) sketch mohr circles showing the relative locations of maximum normal stress and maximum shear stress. (b) determine the safety factor with respect to initial yielding according to the maximum-shear stress theory and according to the maximum-distortion-energy theory.

An electrical motor raises a 50kg load at a construct velencity .calculate the power of the motor, if it takes 40sec to raise the load through a height of 24m(take g =9.8n/g)

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

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?