Quiz-3 Mechanical Behavior of Materials Questions and Complete Solutions Graded A+

Quiz#3 Mechanical Behavior of Materials Questions and Complete Solutions Graded A+ What is brittleness? A. The ability of a material or a group of materials to resist the application of a load or loads without failure B. The plastic flow of material over a long period of time without material disintegration C. The ability of a material to deform outside of the elastic range and not rupture D. The lack of a material's ability to deform outside of the elastic range - Answer: D. The lack of a material's ability to deform outside of the elastic range The transition point between linear and nonlinear behavior on a stress-strain diagram is known as: A. Proportional limit B. Yield Point C. Ultimate Tensile Strength D. Fracture Point - Answer: A. Proportional limit Which of the following instruments is used for measuring deformation? A. Load Cell B. Ohmmeter C. LVDT D. Voltmeter - Answer: C. LVDT What is axial strain? A. Same as lateral strain B. Strain developed in the direction parallel to the direction of loading. C. Strain developed in the direction perpendicular to the direction of loading. D. Change in the deformation remaining once the load is released. - Answer: B. Strain developed in the direction parallel to the direction of loading. Which of the following is NOT a mechanical property? A. Strength B. Stiffness C. Density D. Modulus - Answer: C. Density Unit of load is: A. Pounds (lbs) B. PSI C. Inches D. lb/in - Answer: A. Pounds (lbs) Which of the following materials has highest modulus of elasticity value? A. Wood B. Steel C. Concrete D. Aluminum - Answer: B. Steel 500 kPa (kilo Pascal) is approximately equal to: 1 PSI = 6.89 kPa A. 3445 PSI B. 500 PSI C. 73 PSI D. 34.5 PSI - Answer: C. 73 PSI A large steel slab weighing 20,000 lbs load is supported by four steel rods. Each rod is ¾ in. in diameter. Assume that the rods support equal loads. Calculate the stress in each individual rod. Please note that each rod has circular area. A. 45,249 PSI B. 22,624 PSI C. 11,312 PSI D. 20,000 PSI - Answer: C. 11,312 PSI Compute the compressive stress developed in steel bar (2 inch x 2inch in cross section) if it is subjected to an axial compressive load of 95,000 lb. A. 47,500 PSI B. 23,750 PSI C. 95,000 PSI D. 20,000 PSI - Answer: B. 23,750 PSI Testing a material by applying very short term loading would imply which type of the following loadings? A. Dynamic B. Transient C. Creep D. Static - Answer: A. Dynamic The ability of a material to deform without taking a permanent set when the load is released is known as: A. Elasticity B. Ductility C. Toughness D. Hardness - Answer: A. Elasticity The compressive strength of a material is: A. Load at break B. Ultimate Load C. Yield Strength D. Ultimate load per cross section area - Answer: D. Ultimate load per cross section area Unit of stress is: A. Pounds B. PSI C. Inches D. None of the above - Answer: B. PSI Using concrete with a compressive strength of 3,000 PSI, what would the area of a round pillar have to be to support a 66,000 lb. load? A.22 in2 B. 2.2 in2 C. 0.45 in2 D. 0.045 in2 - Answer: A.22 in2 Which of the following stress-strain curves shown below represent steel (see attachment)? A. Curve A B. Curve B C. Curve C D. Curve D - Answer: B. Curve B What is the sensitivity and range of caliper in the attached picture? A. Sensitivity = 0.001 inch, Range = 5 inches B. Sensitivity = 0.01 inch, Range = 6 inches C. Sensitivity = 0.001 inch, Range = 6 inches D. Sensitivity = 6 inches, Range = 0.001 inch E. Sensitivity = 6 inches, Range = 0.01 inch - Answer: C. Sensitivity = 0.001 inch, Range = 6 inches In the laboratory, four materials, namely A, B, C and D were tested for compression testing. The stress-strain curves obtained from testing are shown below. What type of material is shown by curve A? A. Elastic B. Plastic C. Viscous D. Elastoplastic - Answer: A. Elastic In the laboratory, four materials, namely A, B, C and D were tested for compression testing. The stress-strain curves obtained from testing are shown below. Which of the following curves show strongest material (high strength)? A. Curve A B. Curve B C. Curve C D. Curve D - Answer: A. Curve A During construction of the surface layer of asphalt pavement, two samples were taken every day to measure the asphalt content in the mix to ensure that it is within the specification limits. The target value was set at 5.5 percent with a tolerance of ±0.4 percent. The following asphalt content data were collected (see attached). Calculate approximate value of mean and coefficient of variation (CV = Standard deviation*100/Mean), if standard deviation = 0.303 (round up to one decimal point). A. Mean = 5.1, CV = 5.3 B. Mean = 5.3, CV = 5.1 C. Mean = 5.5, CV = 5.5 D. Mean = 5.9, CV = 5.7 - Answer: C. Mean = 5.5, CV = 5.5