Build a formula sheet that maps each formula to when to use it and the exact trap variant exams like to test

Build a formula reference sheet for the topics below, organized around when to use each formula and the specific way exam questions try to trip people up on it — not just a bare list of equations copied from a textbook.

EXAM AND TOPICS TO COVER
GATE Mechanical Engineering, Fluid Mechanics: Bernoulli's equation, continuity equation, Reynolds number

WHAT'S ALLOWED IN THE ACTUAL EXAM
GATE provides no formula sheet — everything must be memorized

FORMULAS YOU ALREADY MIX UP
I keep confusing when to apply Bernoulli's equation directly versus when I need to account for head loss first

FOR EACH FORMULA, INCLUDE
The formula itself with every variable defined and its unit stated. A one-line trigger: the specific phrase or setup in a question that signals this is the formula to reach for, since exam questions rarely say "use formula X" directly. The single most common trap variant — a case where the obvious-looking formula is actually the wrong one, a unit that needs converting first, or a variable that's easy to misidentify (e.g. confusing initial and final values, or radius and diameter). If two formulas are commonly confused for each other, place them adjacent and add one line distinguishing exactly when each applies, rather than listing them in unrelated sections where the distinction has to be worked out separately. Where the exam allowance means a formula is actually provided on the exam paper itself, mark it clearly as "given on paper — memorize when to use it, not the formula itself" so time isn't wasted memorizing something that will be printed in front of the student anyway.

WHAT NOT TO DO
Do not include a formula's full derivation unless a specific formula's derivation is itself commonly examined as a question type — state which ones fall into that category rather than deriving everything by default, since most students need the sheet for application speed, not re-derivation from scratch.

OUTPUT FORMAT
Grouped by topic, one formula per entry with sub-bullets for: Formula, Trigger, Trap, Given-on-paper status.