Questions in FTRE in Chemistry are pretty doable. Physics is moderate to hard and Maths is quite tough. For Chemistry as previously said, all of it will suffice.
In addition to mechanics in Physics, questions are asked from magnetism and magnetic properties of current. If you wish, you can do it, though not very compulsary.
For Maths, what I would suggest is keep on thinking of a problem till you get the solution. Don't worry if you do only less than 5 questions from some topic in a day, with no help. This will help you increase your thinking capacity and is quite helpful for Maths. This brainstorming is fun and will help you a lot.
Plus, don't worry of these exams much as these are complementary.