Assume for the sake of having values for this problem that an old railroad track was made using cast iron rails with properties equivalent to ASTM A-197 cast iron. Assume that the gap is 8-0.25in at 60F. Assume that the rails can stretch or shrink freely. The rail weighs 60lbf per yard of length. ||-8 40 ft- 8|| a. What cross-sectional area does the rail have based upon its specific weight and weight per unit length? b. At what temperature will the rails touch w/o force (8=Oin)? c. At what temperature will the gap increase to 6=0.5in? d. At what temperature will the normal stress in the rails exceed the ultimate strength of the material in compression?