Hey - i've split your question into its own thread. Your situation is a little bit different to where you posted it.
In Year 11, if you do Physics from the beginning it'll be Unit 1
In my opinion, I think you should relax. For Year 11, all you need is a S (satisfactory) to pass a unit. If you really want to learn a bit, might be worth grabbing a Unit 1/2 textbook for Physics and having a look through that. I wouldn't be worrying yet OR putting too much work into it at this point in time (or even over holidays).
Your school will most likely (I haven't heard of a school that doesn't do this) offer a head start program of some kind, where at the end of the year you'll start the transition into Year 11 by doing like 1-2 weeks worth of Unit 1 work for your subjects next year.
Cheers