A pipe resting on a rock may break if it is weak in which strength types?

• A. Compressive strength
• B. Shear strength
• C. Torsional strength
• D. Tensile and Flexural strength

Answer: (D)

A pipe resting on a rock behaves like a short beam spanning a support, so bending and the resulting tensile stresses on the outer fiber drive failure. The top part of the pipe is pulled in tension while the bottom is compressed. If the pipe is weak in tensile strength, it can crack and fail as it is pulled apart by the bending moment. If the material has low flexural strength, it can’t withstand the bending stress in that scenario, leading to fracture under the same load. Compressive strength matters less here because the inner surface is under compression, and cracks from compression are less typical for this failure mode. Torsional strength would require twisting loads, which aren’t the main cause when a rock simply creates a bend, and shear strength is more about sliding failure along a plane than bending-induced fracture. So the pipe is most likely to break if it’s weak in both tensile and flexural strength.