mhale, You do not need straight A's to become a Pilot in the ADF nor do you need Physics.
Like it says on the Defencejobs.gov.au website. you only need to pass Advance English, Mathematics 2 Unit and Three (3) other Academic Subjects (Which one has to be some type of Science, Chemistry, Physics or Biology if a Grade C was not passed in year 10)
I have spoke to many Pilots including, PC-9/A, Hawk 127, F/A-18, Blackhawks and Seahawks. They have all said the same thing. Just obtain the minimum education requirements ^^. Other things they said are.
*Show leadership potential (School Captain, Manager or Captain of a sport team)
*Show an interest in Aviation (Obtaining a Pilots licence, AAFC, Some flight hours, Aeronautics)
*At your assessment day, know everything a big must!
*Learn to do Algebra in your head and learn how to do mathematics quick in your head.
*The rest basically just show them why they should spend up to 3 million dollars on you, short answer BLOW THEM AWAY!!