Question

au] CE 121 EXAM-1 October 01, 2014 Instructions: This is a closed book Exam, You may use the formsula sheet provided separately 50 Points Write neatly and clearly. Show all intermediate steps. Carry units throughout the solutions. Final answers must be accompanied with units where appropriate Problem 1: State true or false. Please circle your answer 1. Normal force is a foree that acts perpendicular to the area 2. Bending moment is developed when the external loads tend to twist the body 3. Change in length of a body per unit area is called as strain 4. For most ductile metals, modulus of toughness is higher than modulus of resilience 5. For most metals, the stress-strain relationship is linear within elastic zone 6. Higher modulus of elasticity is an indicator higher yield strength (6 points) True / False True / False True/ False True/ False True /False True/False (3 points) Problem 2: Circle all that is true for following sentences 1. Shear Modulus: a) is indicated by the area under shear-stress diagram b) is measured by the conducting a bending test c) is a ratio of lateral strain and longitudinal strain d) is a ratio of shear stress and shear strain in elastic region e) None of the above 2. Young's Modulus for a material a) is calculated by dividing the strain into the stress for the plastic region of the stress-strain diagram b) is correlated with the shear strain and temperature of the material c) is the same whether engineering stress-strain and/or true stress-strain are plotted d) All of the above e) None of the above 3. Modulus of toughness: a) is directly proportional to the Modulus of Elasticity b) is indicated by the area under the stress-strain diagram c) is measured by the conducting a bending test d) is most indicative of how a material could withstand a bomb blast e) All of the above

Answer 1