ENTC 206 Test #1 Questions with verified solution 2023

ENTC 206 Test #1endurance limit - correct answer stress level that fatigue failure will not occur below hardness - correct answer measure of a material's resistance to penetration tensile test - correct answer standard testing method used to generate the stress-strain relationship creep - correct answer continued plastic deformation under a constant load and more prominently with elevated temperature; material may stretch & eventually fail at an applied stress BELOW its yield strength; time related phenomena noncrystalline materials - correct answer amorphous materials examples of noncrystalline - correct answer glass, dense polymers, body tissue, foam, sand ductile if... - correct answer percent elongation greater than 5% brittle if... - correct answer percent elongation less than 5% Van der Waal Bond - correct answer secondary, weaker bond (intermolecular), found in graphite and polymers Cycle Loading - correct answer fatigue testing should be considered when material is subjected to THIS impact testing - correct answer utilized to determine whether a material has the ductile-brittle transition property highest stiffness - correct answer steepest slope on graph how much CO2 is emitted after burning 1 gal of gasoline - correct answer 20 lb. Unit for Stress - correct answer MPa or ksi how much energy saved by using recycled aluminum instead of freshly made aluminum? - correct answer 95% highest embodied energy - correct answer aluminum alloys diameter of most atoms - correct answer 0.1-0.5 nm anisotropic - correct answer material that possesses identical properties mechanical properties along all directions philosophy of conducting a material's LCA (life cycle assessment) is to incorporate the - correct answer Life Cycle Inventory (LCI) into the decision making process for material selections goal of LCA - correct answer making green products embodied energy - correct answer energy required to produce materials from ores & feedstocks how much energy to produce 1 ream of printer paper? - correct answer 2 gallons of gasoline How much energy does it take to make steel from recycled scrap? - correct answer 33% less than to make it from iron ore how much new steel is made from recycled? - correct answer 2/3