A wam of 70 is not easy in any discipline.
thats only because you are stupid.
I had two computer programming subjects ( that I really didnt like at all ) attack my WAM and I had two physics subjects, phys 1A and 1B, and I still managed to get 70% even though I was lucky to do like one tutorial question per week ( and that was the easiest question in the group, usually just a substitution question
, I would have been lucky to have done like one out of every twenty in that tutorial problems book)
I got 63 and 69 for comp 1A and 1B , and 66 and 71 for phys 1A and 1B , and I still managed to get 72 WAM over the first year after those rapings from those screwed up subjects.
You are just failing because you are shit at maths, and an engineer that is shit at maths is gauranteed to fail because you are just going to continue repeating your maths mistakes throughout your degree and will keep losing marks on the same mistakes.