I think relative to the other Asian 5 subjects, it's easy in the sense that you don't have to understand as much to get marks, as you would for say Chemistry or Spesh. With that being said, it doesn't mean that you can do well by not understanding everything, it's just that you can get away with more. In certain situations, you can get away with not understanding where the formula comes from, as long as you can apply it (I'm not saying all, and I'm not encouraging this either). Yes there are questions that ask you to explain why and give proper reasoning, but they're not really the majority, and as pi` has said, people get away with getting these right without having a clue sometimes with the aid of their cheat sheet, (yes in the examiners report they always say that students lose marks for copying explanations off their cheat sheets without interpreting them in the context of the question, but with some understanding you can do this easily, by some I mean what you're supposed to know within the course, not really using too much outside it). Again I'm not encouraging it, I'm just getting at what has happened in the past.
If you want to do well, then learn the material properly, and go outside the course, with that being said, it's not impossible to do well without doing this, unfortunately.
Now for a bit of an anecdote. During year 12, I put a lot of effort into chemistry and spesh (really a lot of effort into chem). I didn't really put that much into physics, probably moreso because of loss of motivation resulting from our teacher marking in a way that contradicted VCAA (some of our sac questions were pulled from past vcaa exams, and giving what vcaa gave in the examiners report was marked wrong).
Anyways, what I'm getting at here is, physics is seen as 'easier' because a lot of those who do it compare it to other Asian 5 subjects, you don't have to put as much effort into physics to get the same score in chem or spesh. You have that cheat sheet to fall back on, to get you out of a pickle. In chem, if you don't know something in the exam, you don't know it and that's it. In physics, there's the off chance you can fall back on your cheat sheet. (Yes there is a bound reference in spesh, but you need more understanding to get through spesh than physics, and you don't have much time to use the bound reference in exam 2 if you need to anyways).
If you had to pick the easier subject/easiest subject to do well in out of the Asian 5 subjects, what would you pick? I'd have to go with physics. I'd also say that the average physics student isn't as great as the average chem or spesh student. Now again, this is only anecdotal but looking back at the demographics of my physics classes compared to say chem, spesh or even methods, on average we didn't have as many that were say aiming high, compared to our chem and spesh classes, if that makes sense. This could have just been my school though.
Now again, I don't encourage this, in an ideal world we'd be learning physics properly. I'm just getting at that with a bit of intelligence some people can get away with a 40+ study score without too much effort (you could even say it's not deserved, I don't think my physics score was deserved). At the same time I saw people put a lot more work into physics, but in the 'wrong way' for vce, and get mid 30's, they worked a lot harder than I did, (I'd call this the right way to learn properly though, which is again unfortunately, and frustrating).
I would argue though that you'd have trouble getting 45+ without knowing and understanding the content properly.
I will say this again, but I don't encourage going about physics this way, it's better to learn everything properly, otherwise you'll have gaps in your knowledge when you get to uni. It's frustrating that the course and system is this way, really frustrating, but that's the way it is. If you want the top scores, this won't work though.
I've kinda looped a bit, and repeated myself. The post isn't thought out well, I guess since I'm pretty frustrated typing it, as a lot of it goes against what I think is right, and want to be right I guess.