Hi there!
I’m from NSW but I just sat the UCAT this year. From my experience, there actually isn’t a Physics section in the UCAT. The UCAT consists of five subtests; Verbal Reasoning (reading and interpreting written passages), Decision Making (logic games, choosing the strongest argument, etc), Quantitative Reasoning (mathematical skills), Abstract Reasoning (interpreting patterns and sequences) and Situational Judgement (centred on ethical decisions, judging the appropriateness + importance of actions).
I believe it is only the GAMSAT (for graduate medical entry) that specifically tests scientific skills. So in light of the above, for the UCAT, Physics knowledge is not necessary.
I hope this helps! If you have any further questions, feel free to ask!