No Mr Wombat, I don't particularly agree with that....
Take 'engines' for example. You could research how they work and find out that the gasses are compressed adiabatically, and find the formulas for thermal efficiency (related to Tmax and Tmin). You could study Youngs Modulus, and use the Ultimate Tensile Strength calculations used in the design of Con-Rods.
Or in Navigation, you could delve into Astral Navigation, how to use a Sextant, and how to calculate the great circle bearing of one Lat/Lon position to another. (as I unfortunately did prior to my PPL.)
It's only by knowing what questions will be asked, that you don't research a subject in too much depth.
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