Final answer:
Options A & B, the creation of a polar plot for a journal bearing typically involves plotting various performance characteristics, like load capacity or friction torque, against rotational speed under different conditions, such as varying temperatures or radial positions.
Step-by-step explanation:
To make a polar plot for a journal bearing, the focus is generally on representing how different performance characteristics vary with changing operational conditions. Among the choices given, the best approach for a polar plot in the context of journal bearings would likely involve plotting load capacity against speed at different temperatures (option A) or plotting friction torque against speed at various radial positions (option B). A polar plot for option A would represent the bearing's capability to support loads at various rotational speeds and at different operational temperatures, which can be critical for understanding the bearing's performance in different working conditions. For option B, a polar plot would show how the frictional forces behave at different distances from the centre of the bearing when it is in motion, which is influential in the design and analysis of bearings. Option C is less likely to be depicted as a polar plot, as radial clearance and load capacity may not necessarily have a naturally cyclic relationship. Option D, plotting temperature against time under different load conditions, is typically represented as a time-series graph rather than a polar plot.