Angola Air Force Academy Entrance Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Quadratic formula

For ax² + bx + c = 0 with a ≠ 0, the solutions are x = (−b ± √(b² − 4ac)) / (2a).

Discriminant

In a quadratic equation, Δ = b² − 4ac. If Δ > 0 there are two distinct real roots; if Δ = 0 one repeated real root; if Δ < 0 no real roots.

Sine rule

In any triangle, a/sin A = b/sin B = c/sin C = 2R, where a, b, c are sides opposite angles A, B, C and R is the circumradius.

Cosine rule

In any triangle, a² = b² + c² − 2bc cos A, where a is the side opposite angle A. It generalises Pythagoras when A is 90°.

Mean and median

The mean is the sum of values divided by their number. The median is the middle value when data are ordered; with an even count, it is the average of the two middle values.

Complement rule

For any event A, P(not A) = 1 − P(A). This rule is useful when the probability of the complement is easier to calculate than the event itself.

Newton's second law

The net force on an object equals its mass times acceleration: F_net = ma. Acceleration is in the same direction as the net force and inversely proportional to mass.

Hydrostatic pressure

Pressure at depth h in a fluid at rest is p = p₀ + ρgh, where p₀ is surface pressure, ρ fluid density, g gravitational acceleration, and h depth.

Bernoulli principle

For steady, ideal, incompressible flow along a streamline, p + ½ρv² + ρgh is constant. Higher speed generally means lower static pressure at the same height.

Ohm's law

For a conductor at constant temperature, current I is directly proportional to voltage V and inversely proportional to resistance R: V = IR.

Lift equation

Lift on a wing is L = ½ρv²SC_L, where ρ is air density, v airspeed, S wing area, and C_L the lift coefficient.

Crase

Crase é a fusão da preposição a com o artigo a ou com pronomes demonstrativos. Ocorre antes de substantivo feminino determinado e não antes de verbo ou palavra masculina.

Concordância verbal

Concordância verbal é a correspondência entre o verbo e o sujeito em número e pessoa. Com sujeito composto anteposto, o verbo normalmente fica no plural.

Texto dissertativo

Texto dissertativo apresenta uma tese e a defende com argumentos. Organiza-se geralmente em introdução, desenvolvimento e conclusão, mantendo coesão e progressão temática.

Ideia principal

Ideia principal é a mensagem central de um texto. Pode estar explícita na tese ou ser inferida; detalhes e exemplos servem para sustentá-la, não para substituí-la.

Mole

One mole contains 6.022 × 10²³ elementary entities. The molar mass of a substance in grams per mole is numerically equal to its atomic or molecular mass in unified atomic mass units.

Molarity

Molarity (M) is the amount of solute in moles divided by the volume of solution in litres: M = n/V. It changes with temperature because solution volume changes.

pH scale

pH = −log[H₃O⁺]. At 25 °C, pH + pOH = 14; pH below 7 is acidic, 7 is neutral, and above 7 is basic.

Oxidation number

Oxidation number is the formal charge an atom would have if electrons were assigned to the more electronegative atom. Free elements are 0; monatomic ions equal their charge.

Present simple

The present simple uses the base verb, adding -s or -es for third-person singular. It describes habits, routines, general truths, and scheduled events.

Subject-verb agreement

A singular subject takes a singular verb, and a plural subject takes a plural verb. Compound subjects joined by and usually take a plural verb; each and every take singular.

Passive voice

Passive voice uses be plus a past participle, for example, “The report was written.” The object becomes the subject, and the agent may be omitted.

Main idea

The main idea is the central point of a passage. It is often stated in a topic sentence or must be inferred from repeated key terms and supporting details.

Angola independence date

Angola proclaimed independence from Portugal on 11 November 1975. Agostinho Neto, leader of the MPLA, became the first president of the independent republic.

Luena Memorandum

The Luena Memorandum was signed in 2002 between the Angolan government and UNITA. It ended the civil war and provided for demobilisation and reintegration of UNITA fighters.

Angola borders

Angola borders the Democratic Republic of the Congo to the north, Zambia to the east, Namibia to the south, and the Atlantic Ocean to the west. Cabinda is an exclave north of the DRC.

Civic duty

A civic duty is a legal or moral obligation of a citizen, such as obeying laws, paying taxes, respecting public property, voting, and defending national sovereignty and the environment.

Contrapositive

The contrapositive of “If P then Q” is “If not Q then not P.” These two statements are logically equivalent; the converse and inverse are not.

Cube net

A cube net is a two-dimensional arrangement of six squares that folds into a cube. Eleven distinct nets exist, and opposite faces are separated by one face in a straight line.

Venn syllogism

In a Venn syllogism, “All A are B” means A is a subset of B, while “Some A are B” means the intersection of A and B is not empty.

BMI formula

Body mass index is mass in kilograms divided by height in metres squared: BMI = kg/m². It is a screening measure and may misclassify muscular individuals as overweight.

VO2max

VO₂max is the maximum rate at which the body can use oxygen during intense exercise. It is expressed in millilitres of oxygen per kilogram of body mass per minute.