When reviewing results of vibration analysis, vibration at a bearing occurs at the same frequency as the motor rpm, with a displacement in the radial direction that is twice that of the axial direction. Which of the following could this indicate?

Correct Answer: Option B — Mechanical unbalance.

Mechanical unbalance is characterized by vibration at the rotational frequency (1x RPM). Because the force is generated by the rotating mass, the radial displacement is typically significantly higher than the axial displacement. This signature distinguishes unbalance from misalignment or looseness, which often exhibit different phase and directional characteristics.