(Solved): The A-36 steel drill shaft of an oil well extends \( 12000 \mathrm{ft} \) into the ground. The pipe ...

The A-36 steel drill shaft of an oil well extends \( 12000 \mathrm{ft} \) into the ground. The pipe used to drill the well is suspended freely from the derrick at \( A \). (Figure 1) The shaft consists of three different sizes of pipe, \( A_{A B}=2.30 \) in. \( ^{2}, A_{B C}=1.80 \) in. \( { }^{2} \), and \( A_{C D}=1.50 \mathrm{in}^{2} \), each having the length and weight per unit length indicated. Figure Determine the maximum average normal stress in pipe string \( A B \). Express your answer to three significant figures and include appropriate units. Part B Determine the maximum average normal stress in pipe string \( B C \). Express your answer to three significant figures and include appropriate units. Determine the maximum average normal stress in pipe string \( C D \). Express your answer to three significant figures and include appropriate units. X Incorrect; Try Again; 2 attempts remaining Part D Determine the elongation of its end \( D \) with respect to the fixed end at \( A \). Express your answer to three significant figures and include appropriate units.