When a shaft mounted on two bearings must be positioned axially, which statement is correct?

The statement that one bearing should be fixed and the other floating is correct because it allows for thermal expansion and axial movement of the shaft. In a system where bearings support a shaft, having one bearing fixed provides a reference point for alignment and stability, while the floating bearing can accommodate changes due to temperature variations, manufacturing tolerances, or shaft deflections.

This configuration prevents excessive stress on the bearings and ensures proper operation of the system over a range of conditions. If both bearings were fixed, any axial movement of the shaft due to expansion or contraction could lead to binding and potential failure. Conversely, if both bearings were allowed to float, the shaft might not be secure enough, leading to misalignment or improper support.