Bending (flexure) is best described as which of the following?

• A. The twisting of an object due to an applied torque.
• B. The behavior of a slender structural element subjected to an external load applied perpendicular to its length.
• C. The fractional change in length due to temperature change.
• D. The frictional force resisting sliding.

Answer: (B)

Bending is how a long, slender member deforms when a load is applied perpendicular to its length. This transverse loading causes the beam to curve, with the top fibers compressed and the bottom fibers stretched while the middle experiences little net strain. It’s distinct from twisting, which comes from torque that rotates the member about its axis; from thermal expansion, which changes length with temperature; and from friction, which is a resisting force to sliding rather than a bending deformation. So describing bending as a slender structural element subjected to an external load perpendicular to its length best captures the concept.