Tackling an exam problem is not, in principle, any different from tackling a problem from a chapter. The difference is that in two hours you must choose carefully what to solve, in what order, and with what level of detail. Five practical guidelines, to be followed in order.
The five steps
Overview reading → Choice → Schematisation → Step-by-step breakdown → Final check.
1. Overview reading (5 minutes). Read both problems and all the questions before starting. Identify the dominant area of each problem (is it mechanics? induction? relativity?). Judge at a glance which one you feel most confident about.
2. Choice (quick, final). Once you have chosen the problem, do not go back on it. Time spent changing your mind is always time lost.
3. Schematisation. Restate the problem in your own words. Always draw a diagram: free-body diagram, path, circuit, graph. Indicate the positive directions of the axes, the known constants, the unknowns.
4. Breaking it into small steps. A multi-topic problem is always solved in stages: first kinematics, then dynamics, then energy, and so on. Clearly label each stage on the sheet, and state which physical law you are applying.
5. Final check (5–10 minutes set aside). Check units, signs, limits, orders of magnitude.
The absurdity test
If the result is ” kg of diesel to get into town”, something is wrong. A plausible order of magnitude is often the quickest way to spot a calculation error.