Which component reduces friction and supports shafts?

• A. Motor Starter
• B. Encoder
• C. Breaker
• D. Bearing

Answer: (D)

Rotating machinery needs a component that both supports the shaft and minimizes friction in its moving parts. A bearing provides a low-friction interface between the shaft and its housing, allowing smooth rotation while taking on radial loads and, in many designs, axial loads as well. The rolling elements inside a bearing (balls or rollers) convert sliding friction into rolling friction, and lubrication further reduces wear and heat, improving efficiency and longevity. The other options perform electrical or sensing roles rather than mechanical support or friction reduction: a motor starter controls power to the motor, an encoder measures position or speed, and a breaker protects electrical circuits. So the component that best fits both tasks is the bearing.