Axial Stress: 2017 #71

Problem 71. Which action places the most axial force on a joint of 9 5/8 inch 47 lb/ft N-80 casing?

(A) Falling in a vertical hole at ½ foot per second until an abrupt & level impact.
(B) Injecting 10 lb/gal mud into the casing at 400 psig.
(C) Pulling it through a hole with a  3  0.6 per 100 ft dog leg severity.
(D) A & C are within 30% of each other & create the most axial force

Note this entire problem is solved on 6 DTC 1 (GB).
Answers are merely multiples of GB examples (lbf):

Use casing: 9.625 od & 8.681 ID (Redbook).
Δσz − shock = 1,780(Δv) = 1,780(1/2 ft/s) = 890 psi (1/20 Guidebook example)...
Fshock = Δσz − shock(As) = 890 lb/in2 (13.572 in2) = 12M...

Solution: A: 12M lbf (1/20 GB w/ conversion), B: 24M (1/10 GB), C: 17M (1/10 GB)