Plain Bearings are best described as which of the following?

• A. The simplest type of bearing, comprised of just a bearing surface and no rolling element.
• B. A rolling element bearing with balls or rollers.
• C. A sealed, lubricated bearing used for high-speed applications.
• D. A magnetic bearing using fluid film.

Answer: (A)

Plain bearings are defined by sliding contact between two surfaces without any rolling elements. They rely on a bearing surface (often a sleeve or bushing) and lubrication to reduce friction and wear, making the design simple and cost-effective for many loads and moderate speeds. That straightforward, sliding-contact nature is what distinguishes them from bearings that use balls or rollers, which are rolling-element bearings. The option describing the plain bearing as the simplest type with no rolling element matches this idea exactly. The other choices describe bearing types that include rolling elements or rely on magnetic or hydrostatic principles, which are not plain bearings.