What is a common use of bearings in machines?

Bearings are primarily used in machines to facilitate rotational motion. Their main function is to reduce friction between the moving parts, allowing components such as shafts, wheels, or gears to rotate smoothly. By providing a low-friction interface, bearings enable efficient movement and enhance the performance of machinery. This is crucial in a variety of applications, from simple household products to complex industrial equipment, where consistent and reliable rotational motion is necessary for the machinery to operate effectively.

The other options pertain to functions that are not the primary roles of bearings in machines. For example, while some components in mechanical systems may store energy, absorb shocks, or insulate heat, these tasks are not typically associated with bearings. Bearings focus on enhancing movement rather than storing energy, damping shock loads, or providing thermal insulation.