Chapter 3 MECHANICAL PROPERTIES of MATERIALS

Chapter 3 MECHANICAL PROPERTIES OF MATERIALS Multiple Choice Quiz There are 24 correct answers in this multiple choice quiz (some questions have multiple answers that are correct). To achieve a perfect score on the quiz, all correct answers must be given. Each correct answer is worth 1 point. Each omitted answer or wrong answer reduces the score by 1 point. Percentage score on the quiz is based on the total number of correct answers. 3.1 Which of the following are the three basic types of static stresses to which a material can be subjected (three correct answers): (a) compression, (b) hardness, (c) reduction in area, (d) shear, (e) tensile, (f) true stress, and (f) yield? 3.2 Which one of the following is the correct definition of ultimate tensile strength, as derived from the results of a tensile test on a metal specimen: (a) the stress encountered when the stressstrain curve transforms from elastic to plastic behavior, (b) the maximum load divided by the final area of the specimen, (c) the maximum load divided by the original area of the specimen, or (d) the stress observed when the specimen finally fails? 3.3 If engineering stress and true stress were measured simultaneously during a tensile test, which would have the higher value: (a) engineering stress or (b) true stress? 3.4 If engineering strain and true strain were measured simultaneously during a tensile test, which would have the higher value: (a) engineering strain or (b) true strain? 3.5 The plastic region of the stressstrain curve for a metal is characterized by a proportional relationship between stress and strain: (a) true or (b) false? 3.6 Hooke’s Law defines which one of the following regions of the stress strain relationship for engineering materials: (a) elastic region, (b) plastic region, or (c) neither? 3.7 The modulus of elasticity is also known as which one of the following: (a) elastic limit, (b) strain hardening exponent, (c) strength coefficient, or (d) Young’s modulus? 3.8 Which one of the following materials has the highest modulus of elasticity: (a) aluminum, (b) diamond, (c) steel, (d) titanium, or (e) tungsten? 3.9 The flow curve describes the property of metals known as which one of the following: (a) ductility, (b) engineering strain, (c) fracture stress, (d) strain hardening, or (e) tensile strength? 3.10 Which one of the following types of stress strain relationship best describes the behavior of brittle materials such as ceramics and thermosetting plastics: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above? 3.11 Which one of the following types of stress strain relationship best describes the behavior of most metals at room temperature: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above? 3.12 Which one of the following types of stress strain relationship best describes the behavior of metals at temperatures above their respective recrystallization points: (a) elastic and perfectly plastic, (b) elastic and strain hardening, (c) perfectly elastic, or (d) none of the above?

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3.13 The transverse rupture strength is a property usually associated with which one of the following material types: (a) ceramics, (b) metals, (c) plastics, or (d) rubber? 3.14 The shear strength of a metal is commonly determined in which one of the following tests: (a) bending test, (b) compression test, (c) flexure test, (d) tensile test, or (e) torsion test? 3.15 The shear strength of a metal is usually (a) greater than or (b) less than its tensile strength? 3.16 Hardness is best defined as which one of the following: (a) energy absorbed by a material when an object strikes its surface, (b) resistance to bending, (c) resistance to permanent indentation, or (d) resistance to scratching? 3.17 Most hardness tests involve pressing a hard object into the surface of a test specimen and measuring the resulting indentation or its effect: (a) true or (b) false? 3.18 Which one of the following materials has the highest hardness: (a) alumina ceramic, (b) gray cast iron, (c) hardened tool steel, (d) high carbon steel, or (e) polystyrene? 3.19 The formation of new strain-free grains in a metal that has been heated to an elevated temperature is called which one of the following: (a) hot hardness, (b) recrystallization, (c) strain hardening, or (d) strain softening? 3.20 Viscosity can be defined as the ease with which a fluid flows: (a) true or (b) false? 3.21 A Newtonian fluid is a fluid best defined by which one of the following: (a) its viscosity decreases as shear rate increases, (b) its viscosity decreases as temperature increases, (c) its viscosity increases as shear rate increases, (d) its viscosity increases as temperature increases, (e) its viscosity remains constant as shear rate changes, or (f) its viscosity remains constant as temperature changes? 3.22 Viscoelasticity can be defined as the property of a material that determines the strain it experiences when subjected to combinations of stress and temperature over time: (a) true or (b) false?