At what point is the shear due to bending a maximum in shafts?

• A. Minimum
• B. Constant
• C. Maximum also
• D. Zero

Answer: (D)

In the context of bending in shafts, the shear force reaches its maximum at the points of application of external loads or at locations where the geometry changes—however, it is precisely at the points of maximum bending moment along the length of the shaft that shear is zero.

When a shear diagram is drawn for a shaft subjected to bending, the bending moment is highest at the center of the load application and decreases towards the supports. This relationship leads to the realization that at locations of maximum bending moment, the shear forces are zero.

In summary, while shear force is influenced by the amount of bending at various points along the shaft, it specifically becomes zero at the points of maximum bending moment, thus reflecting a fundamental principle in the mechanics of materials regarding shear and bending relationship.