1. 2. 3. 4. Aluminum doesn't have a fatigue limit. How does this knowledge affect the design and maintenance of aircraft? A round bar with a cross-sectional area of 130 mm is pulled on a tensile testing machine. If the reduction in area is 28%, what is the final cross-sectional area of the specimen? What is its final diameter? A hollow torsion specimen develops a shear stress of 7,000 psi under a torque of 420 ft. lb. The average radius is 0.9 in.. What is the wall thickness, t, in inches? Use a micrometer or calipers to measure the diameter of a steel paperclip, in inches. If the wire in the paperclip is pulled with a load of 7 lb. on a tensile testing machine, what is the tensile stress in the wire, in psi? How much strain will develop? Note: Esteel 3010 psi. 5. How would you explain creep to a 5th grader? 6. 7. The two main hardness tests for metals are Brinell and Rockwell. Which of these methods is more similar to the Shore durometer test? How is it similar? How would you rewrite chapter 5 to make the content more understandable and more interesting? What would you add, and what would you cut?