Imagine that you are the architect that designed the school. Identify five safety hazards that should be included in the design of the school; that is safety measures that must be included in the design of the school making it safe to students and teachers and all other persons that will use the school.

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?

Afan that can provide air speeds up to 60 m/s is to be used in a low-speed wind tunnel with atmospheric air at 35 c. if one wishes to use the wind tunnel to study flat-plate boundary layer behavior up to reynolds numbes of re 10, what is the minimum plate length that should be used? at what distance from the leading edge would transition occur if the critical reynolds nurnber were rer,e = 5 × 105?

Acountershaft is supported by two tapered roller bearings using indirect mounting. the radial bearing loads are 1120 lb for the left-hand bearing and 2190 lb for the right-hand bearing. the shaft rotates at 400 rpm and is to have an l10 life of 40,000 hours and an application factor of 1.4. assume ka2k 15, and find the required radial rating of each bearing