ENADE Engenharia Mecânica common mistakes
ENADE Engenharia Mecânica · Understand the traps and how to avoid them.
Starting the discursive answer with the calculation and delivering the result as a bare number, with no statement of the adopted model, hypotheses, or unit system.
Candidates treat the discursive items like the objective ones and rush to the formula, assuming the numeric result is what is graded; the exam rubric explicitly rewards the description of the method and the justification of hypotheses, and many items carry more weight for the reasoning than for the arithmetic.
What to do instead
Before calculating, write a short block: 'Model adopted – hypotheses – properties/data used – units'. Reserve the first three or four lines of the answer for this, and only then do the algebra; finish by checking that each hypothesis was actually used and that units are consistent throughout.
Treating the discursive question as a request for a memorized definition, transcribing a textbook paragraph that answers a neighbouring question instead of the one asked.
The candidate recognizes a familiar keyword (e.g., fatigue, welded joint, refrigeration cycle) and dumps the associated block of theory, without parsing the command verb ('compare', 'justify', 'dimension', 'evaluate the viability of'). Reading time is short and anxiety pushes toward writing immediately.
What to do instead
Underline the command verb and the object of the sentence in the statement, then write a one-line outline answering exactly that verb before drafting; discard any paragraph that does not serve the outlined answer.
Applying a formula without checking the validity domain of its hypotheses (e.g., using the Euler buckling load for a slender column with slenderness below the transition value, or a linear elastic model in a plastic regime).
Formula-driven preparation: candidates memorize expressions per topic but do not associate each with its range of validity, and the exam deliberately sets items at the boundary between regimes to test exactly that judgement.
What to do instead
For each core formula in the syllabus, keep a card listing hypotheses and validity limits (slenderness ratio, elastic limit, steady state, Newtonian fluid, small strain, ideal gas). In the answer, explicitly state which hypothesis holds and compute the transition parameter before choosing the model.
Presenting intermediate results and final results without units, or mixing units within the same calculation (mm with m, kW with W, rpm with rad/s), producing a numerically correct but physically wrong answer.
Candidates work symbolically and plug numbers at the end, losing track of magnitude; Brazilian engineering courses alternate between SI and common industrial units (kgf, cv, rpm, kcal/h), and the exam exploits that mixture.
What to do instead
Adopt a single rule: convert every given quantity to SI at the start, writing the conversion as an explicit line, and carry units through the symbolic manipulation. At the end, verify dimensional homogeneity and do an order-of-magnitude sanity check.
Ignoring the figure, diagram, or table supplied in the statement and answering from the generic theory, missing the specific data (dimensions, boundary conditions, property values) that the item requires.
Habit of skimming the text and skipping graphical information under time pressure; also unfamiliarity with reading technical drawings, free-body diagrams, and property tables quickly.
What to do instead
Read the statement twice: first for the command, second exclusively to extract data from the figure or table, writing each relevant value with its unit on the answer sheet before reasoning. Train by solving items where the figure is indispensable.
Choosing the alternative that matches a memorized phrase rather than the one that is physically consistent, especially in items with plausible but inverted statements (e.g., confusing thermal conductivity with convective coefficient, or stress with strain).
Objective items are built with distractors taken from common conceptual confusions; recognition memory triggers on familiar wording and bypasses the actual verification of the statement.
What to do instead
For each alternative, mark V or F with a one-word justification in the margin before choosing. If no justification comes to mind, treat the alternative as false. Keep a personal list of the conceptual pairs most often confused.
In thermodynamics and fluid mechanics items, applying energy conservation without defining the control volume and its boundaries, omitting the work and heat terms that cross them.
Candidates learn the first law as an algebraic equation and not as a balance over a chosen region; without fixing the boundary, signs of work and heat become arbitrary and mass fluxes are forgotten.
What to do instead
Always draw the control volume and label every crossing flux (mass, heat, work) with its sign convention before writing the balance. State in words what enters and what leaves, then write the equation to match the drawing.
In mechanics of materials and machine design items, computing stresses without checking the strength or fatigue criterion, or using the yield strength where the fatigue limit or the allowable stress is required.
The candidate stops at the stress calculation because that is the most practiced step; the verification against a criterion requires selecting the correct failure mode (static, fatigue, buckling, contact), which is the part least trained.
What to do instead
Structure every design answer in three explicit steps: (1) solicitations, (2) stresses, (3) verification against the applicable criterion with the safety factor stated. Justify the choice of criterion in one sentence before substituting numbers.
Answering manufacturing-process items with a generic description of the process instead of relating process parameters to the resulting part quality (e.g., welding current to penetration, cutting speed to tool life, cooling rate to microstructure).
Process content is often studied descriptively, as a catalogue of steps, without the cause-effect links that the exam asks for; candidates reproduce the sequence but cannot explain defects or parameter choices.
What to do instead
Study each process through a parameter–mechanism–consequence table (parameter, physical mechanism, effect on the part, typical defect). In the answer, name the parameter, the mechanism, and the consequence explicitly.
Running out of time because the candidate spends too long on one discursive item, leaving objective items or the final discursive item blank.
No time plan; perfectionism on the first discursive question, erasing and rewriting, while the objective items are worth a large share of the grade and are quick to answer.
What to do instead
Set a written budget before starting (e.g., a first pass over the objective items in a fixed time, then the discursive items in order of confidence), keep a visible clock, and never leave an item blank: write the model and the hypotheses even when the numeric result is incomplete.