An employee is required to unload 30 cm cardboard cubes from a pallet (15 cm thickness) and place them on a conveyor that is 80 cm high. The cartoons are unloaded at 6 cartons per minute. Each pallet has one layer of cartons containing 16 cartons. The operation requires the worker to twist approximately 900 while turning to unload the cartoon on to the conveyor. A maximum of twelve pallets are unloaded during the first hour of each shift (the activity takes place only once per shift). Find the recommended weight limit for the activity.

If you were designing a bumper for a car, would you prefer it to exhibit elastic or plastic deformation? why? consider the functions of a bumper in both a minor "fender-bender" and a major collision.

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?

Vibration monitoring this technique uses the noise or vibration created by mechanical equipment and in seme cases by plant systems to detemine their actual condtion. a)- true b)- false