Two plates 4ft  x 8 ft plate ½ inch thick is to be joined lengthwise. A welding machine to be used has a welding rate of 20 inch/minute. How long will it take to join the plates?

The frame of a space shuttle type vehicle must have a high yield strength and high stillness, and the most important design factor is weight. Of all the materials presented in this chapter, what material might be the most suitable for the frame of a space shuttle? Assume that there will be both tensile and compressive stresses. For a space shuttle, cost is not a limiting factor. (a) You can eliminate entire classes of materials from consideration with a brief statement about their unsuitability. (b) What material has the highest specific yield strength? Give the yield strength, specific gravity, specific yield strength, elastic modulus, and specific elastic modulus for this material. (c) What material has the highest specific elastic modulus? Give the yield strength, specific gravity, specific yield strength, elastic modulus, and specific elastic modulus for this material. (d) Compare the materials with the highest specific yield strength and highest specific elastic modulus for suitability in the space shuttle frame. (C) Discuss the suitability of the top-rated material for this design from the viewpoint of the ability to produce a frame.